Panitumumab Plus Trifluridine-Tipiracil as Anti–Epidermal Growth Factor Receptor Rechallenge Therapy for Refractory RAS Wild-Type Metastatic Colorectal Cancer

This randomized clinical trial assesses progression-free survival among patients with RAS wild-type metastatic colorectal cancer receiving panitumumab plus standard-of-care trifluridine-tipiracil as third-line therapy.


PROTOCOL SYNOPSIS Study Title
Phase II randomized study evaluating the efficacy of panitumumab (VEctibix) and Trifluridine-Tipiracil (LOnsurf)

Background
The Epidermal Growth Factor Receptor (EGFR) targeted therapy with the monoclonal antibodies cetuximab or panitumumab represents a major step forward in the treatment of RAS wild type (WT) metastatic colorectal cancer (mCRC), given the relevant efficacy in terms of progression-free survival (PFS), overall survival (OS), response rate (RR), as well as quality of life (QoL), observed in several phase III clinical trials among different lines of treatment. However, the clinical benefit observed with these agents is limited to only a subset of patients and responses are often transient due to the development of various mechanisms of resistance. Several studies have provided new insights into molecular basis of EGFR inhibitors resistance and have identified mutations in KRAS, NRAS, BRAF and EGFR extracellular domain (ECD) as well as the amplification of ERBB2 and MET, as biomarkers of both primary and/or acquired resistance to these drugs. Unraveling the biology underlying the complex mechanisms of resistance have been useful for developing rational combination therapies in order to revert or overcome resistance. Rechallenge with an alternative anti-EGFR monoclonal antibody (MoAb) after failure with an agent of the same family has been proposed as strategy to overcome drug resistance. However, panitumumab, as single agent, has demonstrated to provide minimal benefit in patients with KRAS WT mCRC who have experienced progression to cetuximab as prior therapy. The hypotheses that pre-existing sensitive subclones may emerge after treatment breaks with anti-EGFR MoAb has led the design of several clinical trials prospectively evaluating the rechallenge with anti-EGFR MoAbs in the third-line setting after a response to a first-line therapy with anti-EGFR drugs. Trifluridine-Tipiracil demonstrated to be effective in the treatment of refractory mCRC. Anti-EGFR agents in combination with Trifluridine-Tipiracil have shown preliminary activity in SW48 (KRAS WT) xenograft models. Panitumumab in combination with Trifluridine-Tipiracil could be a valid therapeutic option for mCRC RAS WT patients that achieved a major response in the first line of therapy to panitumumab or cetuximab as third line rechallenge treatment.

Rationale
The aim of this study is to investigate a rechallenge strategy of panitumumab in combination with Trifluridine-Tipiracil as compared to standard third line therapy (Trifluridine-Tipiracil) in patients with RAS WT mCRC treated in first line with chemotherapy in combination with an anti-EGFR drug that have had a clinical benefit (complete or partial response) from treatment.

Primary Objectives
To explore the efficacy of panitumumab in combination with Trifluridine-Tipiracil vs standard third line therapy (Trifluridine-Tipiracil) as measured by PFS

Secondary Objectives
To compare the activity of panitumumab in combination with Trifluridine-Tipiracil vs standard third line therapy (Trifluridine-Tipiracil) as measured by ORR To compare the efficacy of panitumumab in combination with Trifluridine-Tipiracil vs standard third line therapy (Trifluridine-Tipiracil) as measured by OS To explore the safety and tolerability of panitumumab in combination with Trifluridine-Tipiracil vs standard third line therapy (Trifluridine-Tipiracil)

Study plan
This is a randomized phase II, open label, two arm study, evaluating the efficacy of panitumumab in combination with Trifluridine-Tipiracil as third line therapy, after a first line containing an anti-EGFR agent panitumumab (at least 70% of study population) or cetuximab.

Sample size
The study is designed to have 80% power to detect a hazard ratio for progression of 0.56 (a 44% reduction in risk) in the Trifluridine-Tipiracil + panitumumab group as compared with the Trifluridine-Tipiracil group, with a two-sided type I error rate of 0.1. Given the treatment assignment ratio of 1:1 (Trifluridine-Tipiracil : panitumumab + Trifluridine-Tipiracil), we calculate that at least 74 events (progression) in 112 subjects (56 in the control group and 56 in the treatment group) would be required for the primary analysis.

Inclusion criteria
Histologically proven diagnosis of colorectal adenocarcinoma Diagnosis of metastatic disease RAS (NRAS and KRAS exon 2,3 and 4) wild-type in tissue at initial diagnosis Efficacy of a first line therapy containing an anti-EGFR agent (panitumumab or cetuximab) with a major response achieved (complete or partial response) Progression after a second line therapy Available and adequate baseline tumour tissue sample Measurable disease according to RECIST criteria v1.1 Male or female patients > 18 years of age ECOG Performance Status 0-1 Life expectancy of at least 3 months Adequate bone marrow, liver and renal function If female and of childbearing potential, have a negative result on a pregnancy test performed a maximum of 14 days before initiation of study treatment If female and of childbearing potential, or if male, agreement to use adequate contraception (eg, abstinence, intrauterine device, oral contraceptive, or double-barrier method) Signed informed consent

Exclusion criteria
Any contraindication to use Trifluridine -Tipiracil or Panitumumab More than two previous lines of treatment Active uncontrolled infections Past or current history of malignancies other than colorectal carcinoma, except for curatively treated basal and squamous cell carcinoma of the skin or in situ carcinoma of the cervix Pregnancy Breastfeeding Interstitial lung disease or pulmonary fibrosis Grade III or IV heart failure (NYHA classification)

Statistical methods
The study is designed to have 80% power to detect a hazard ratio for progression of 0.56 (a 44% reduction in risk) in the Trifluridine-Tipiracil + panitumumab group as compared with the Trifluridine-Tipiracil group, with a two-sided type I error rate of 0.1. Given the treatment assignment ratio of 1:1 (Trifluridine -Tipiracil: Panitumumab + Trifluridine -Tipiracil), we calculate that at least 74 events (progression) in 112 subjects (56 in the control group and 56 in the treatment group) would be required for the primary analysis.
The median period of follow-up will be calculated for the entire study cohort according to the reverse Kaplan-Meier method. Distributions of time-to-event variables will be estimated with the use of the Kaplan-Meier product-limit method. The stratified log-rank test will be used as the primary analysis for comparison of treatment groups. Cox proportionalhazards modeling will be also performed as supportive analyses. Subgroup analyses of progression-free survival will be performed by means of an interaction test to determine the consistency of the treatment effect according to key baseline characteristics. Overall survival will be analyzed with the same methods used for the analysis of progression-free survival. The objective response rate and the incidence of adverse events in the different groups will be compared with the use of the chi-square test for heterogeneity. All statistical tests will be two-sided, and P values of 0.05 or less will be considered to indicate statistical significance. Odds ratios and 95%  (Mayer et al 2015).
The recent advances made in the knowledge of tumor biology and molecular genetics have further influenced the treatment of mCRC patients, with the introduction of novel molecularly targeted agents: monoclonal antibodies (MoAbs) against vascular endothelial growth factor confidence intervals will be estimated with a logistic-regression model, and hazard ratios and 95% confidence intervals will be estimated with a Cox proportional hazards model.

STUDY RATIONALE
Advances in the molecular understanding of the complex mechanisms of resistance to anti-EGFR MoAb, with the use of innovative technologies, such as liquid biopsies, are leading to the development of novel approach to revert or overcome resistance.
Rechallenge with an alternative anti-EGFR monoclonal antibody (MoAb) after failure with an agent of the same family has been proposed as strategy to overcome drug resistance. Recent studies have suggested a limited benefit from a retreatment strategy with anti-EGFR therapy in mCRC.
In a phase II study 39 patients with KRAS exon 2-wt mCRC who had previously progressed following an initial clinical benefit to cetuximab-based therapy, were retreated with cetuximab and irinotecan. Results demonstrated an overall response rate of 53.8 %, stable disease rate was 35.9 %, and the median progression-free survival was 6.6 months (Santini et al 2012). In PANERB trial 32 patients with KRAS wild-type mCRC were prospectively treated with cetuximab and irinotecan followed by panitumumab monotherapy after progression. In 11 patients who had previously responded to cetuximab and irinotecan, an objective response rate of 22 % to panitumumab, including a disease control rate (objective response plus stable disease) of 73 % was observed (Wadlow et al 2012). In heavily pre-treated patients without acquired resistance to prior cetuximab-based regimens, panitumumab obtained 67 % disease control rate and 30 % objective response rate, with median PFS of 4.2 and median OS of 9.6 months (Pietrantonio et al 2013).

Study Hypothesis
The aim of this study is to investigate a rechallenge strategy of panitumumab in combination with Trifluridine-Tipiracil as compared to standard third line therapy (Trifluridine-Tipiracil) in patients with RAS WT mCRC, treated in first line with chemotherapy in combination with an anti-EGFR drug and have obtained a clinical benefit (complete or partial response) from treatment.

Primary Objective
To explore the efficacy of panitumumab in combination with Trifluridine-Tipiracil vs standard third line therapy (Trifluridine-Tipiracil) as measured by PFS

2.2.2Secondary Objectives
Compare the activity of panitumumab in combination with Trifluridine-Tipiracil vs

Exploratory secondary objectives
To explore the mutational profile and evaluate acquired mutations in plasma circulating cell-free DNA (cfDNA) and to explore the relationship with panitumumab in combination with Trifluridine-Tipiracil activity

Primary Endpoint
PFS: defined as the time from randomization to the earliest documented disease progression or death due to any cause of panitumumab in combination with Trifluridine-Tipiracil vs Trifluridine-Tipiracil

Exploratory secondary endpoints
Genomic analysis of blood samples collected baseline, during treatment period and at end of treatment

Inclusion Criteria
Patients must meet the following criteria for study entry: Signed informed consent to any study-specific procedure.

Age ≥18 years
Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 (see Appendix 1) Histologically confirmed adenocarcinoma of the colon or rectum Patient who is refractory to chemotherapy is defined as a patient who didn't respond (obtaining a PR or CR) from the beginning of the treatment (primary refractory) or, after initial response, experiences progression while on treatment (secondary refractory); Patient who is intolerant to chemotherapy is defined as a patient who has been withdrawn from standard treatment due to unacceptable toxicity warranting discontinuation of treatment and precluding retreatment with the same agent prior to progression of disease. This patient will also be eligible to enter the study; Able to take medications orally (i.e., no feeding tube) Available and adequate baseline tumour tissue sample Adequate organ function as defined by the following laboratory values: Hemoglobin value of ≥9.0 g/dL.
Platelet count ≥100 × 10 9 /L Total serum bilirubin of ≤1.5 mg/dL (except for Grade 1 hyperbilirubinemia due solely to a medical diagnosis of Gilbert's syndrome) Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤3.0×upper limit of normal (ULN); if liver function abnormalities are due to underlying liver metastasis, AST and ALT ≤5 × ULN Creatinine clearance ≥ 60 mL/min (assessed with Cockcroft-Gault formula) Women of childbearing potential must have been tested negative in a serum pregnancy test within 14 days prior to first day of test drug administration Note: Female participants of childbearing potential and male participants with partners of childbearing potential must agree to use a highly effective method of birth control (i.e., pregnancy rate of less than 1% per year) during the study and for 6 months after the discontinuation of study medication A women is not considered to be of childbearing potential if she has become amenorrheic for > 12 months and has follicle-stimulating hormone level 40 IU/L Contraceptive methods that result in a low failure rate when used consistently and correctly include methods such as combined hormonal contraception associated with inhibition of ovulation (oral, intravaginal, transdermal), progestogen-only hormonal contraception associated with inhibition of ovulation (oral, injectable, implantable), some intrauterine devices (IUDs), intrauterine hormone-releasing system (IUS), true sexual abstinence, bilateral tubal occlusion, or a female partner who is not of childbearing potential or a male partner who has had a vasectomy. Women and female partners using hormonal contraceptive must also use a barrier method i.e. condom or occlusive cap (diaphragm or cervical/vault caps).

Exclusion Criteria
A subject is excluded from the study if any of the following criteria is met: Unlikely to cooperate in the study

STUDY DESIGN AND PROCEDURES
This is a randomized phase II, open label, two arm study, evaluating the efficacy of panitumumab in combination with Trifluridine-Tipiracilas third line therapy, after a first line containing an anti-EGFR agent panitumumab(at least 70% of study population) or cetuximab.
The primary objective is to evaluate the efficacy of panitumumab in combination with Trifluridine-Tipiracil (as measured by PFS) in pretreated mCRC patients. The secondary objective is to evaluate the ORR, OS and safety. Patients will be randomized in a 1:1 ratio to receive: Arm A: Trifluridine-Tipiracil Arm B: Panitumumab + Trifluridine-Tipiracil

Sample size
A total of 112 patients, 56 for arm, will be enrolled.

Study Duration
It is planned that patient's enrolment will be completed in 18 months with an expected total study duration of approximately 30months considering an additional 12 months of follow up from last patient enrolled.

Treatment plan
Eligible Patients (see inclusion and exclusion criteria see sections 3.1 and 3.2) will be randomized to receive a third line treatment with panitumumab in combination with Trifluridine-Tipiracil or Trifluridine-Tipiracil as monotherapy (see Study Design, Figure 1).
Randomization will be stratified by baseline Eastern Cooperative Oncology Group (ECOG PS: 0 vs 1), prior anti-EGFR agent administered (panitumumab at least 70% of study population vs cetuximab), and tumor sidedness (right vs left colon). In particular, the tumors located from the caecum to a point approximately half the two-thirds of the way along the transverse colon will be considered as "right colon", whilst the tumors located from the distal third of the transverse colon to the rectum will be considered "left colon".
Treatment will be administered in 28-days cycles until disease progression, unacceptable toxicity, withdrawal of consent or death due to any cause.
All patients will be closely monitored for safety and tolerability during all cycles of therapy, at the treatment discontinuation visit, and during the follow-up period. The NCI v.5.0 will be used to characterize the toxicity profile of the study treatments on all patients.
Patients who discontinue treatment for reasons other than disease progression (e.g., toxicity) will continue scheduled tumor assessments until disease progression, withdrawal of consent, study termination by Sponsor, or death, whichever occurs first. In the absence of disease progression, tumor assessments should continue regardless of whether patients start a new anticancer therapy, unless consent is withdrawn. All patients will be followed for survival unless consent is withdrawn (see section 4.4.5).

Panitumumab administration
Panitumumab will be administered as a 6 mg/kg intravenous infusion over 60 minutes every 2 weeks (q2w) of a 28-day cycle (Day 1 and Day 15) (see Figure 2.

2)
Note: If the subject's weight changes by 10% during the course of the study, the dose of panitumumab will be recalculated. No ideal body weight should be used for the calculation of BSA.
Panitumumab must be diluted in pyrogen-free 0.9% sodium chloride for injection using aseptic technique to a recommended total volume of 100 mL. Doses higher than 1000 mg should be For details on prepared drug storage and use time of drugs under room temperature and refrigeration, please refer to pharmacy reference sheets.
Pre-emptive skin treatment regimen is mandatory, if there are not contraindications and it must be administered one day before the administration of the first Panitumumab dose and continued through weeks 1 to 6 (Please refer to paragraph 4.

"Concomitant medication" and
Permissible concomitant medications and treatments" for more details).

Trifluridine-Tipiracil administration
Trifluridine-Tipiracil will be administered at 35 mg per square meter orally twice daily, with a glass of water within 1 hour after completion of morning and evening meals, 5 days a week, with 2 days of rest, for 2 weeks, followed by a 14-day rest period (see If at the beginning of the next treatment cycle, a patient's body weight decreases by ≥10% from baseline, the body surface area (BSA) and the dosage of Trifluridine-Tipiracil has to be adjusted (See Table 1 and Table 8).
No increase in Trifluridine-Tipiracil dose due to increase in BSA is permitted.
If doses are missed or held, the patient should not make up for missed doses.
Any missed doses reported by the patient should be recorded in the patient's diary.
Extension of study treatment into Days 6 to 7 or into the rest period (Days 13 through 28) is not permitted.

General Recommendation
Subjects should be assessed for toxicity before each treatment cycle. Toxicity will be graded according to the NCI CTCAE Version 5.0. Reasons for dose modifications, delays or interruptions, the supportive measures taken, and the outcome, will be documented in the patient's chart and recorded in the eCRF. Guidelines to be followed in the case of AEare : For toxicities considered by the investigator unlikely to develop into serious or life-threatening events (e.g. alopecia, altered taste etc.), treatment will be continued at the same dose without reduction or interruption.
Where several toxicities with different grades or severity occur at the same time, the dose modifications applied should be the greatest reduction applicable.
Once a dose has been reduced it should not be increased at a later time.
If toxicity requires a dosing delay of all study drugs for more than four weeks, the patient will be withdrawn from the study for toxicity reasons. Note: For patients randomized to Arm B (Panitumumab+ Trifluridine-Tipiracil) ( Figure 2.

2):
If, in the opinion of the Investigator, a toxicity is considered to be due solely to one drug, the dose of the other drug does not require modification.
If a delay related to a treatment alone is required, the other study drug should be delayed as well.

Grade 2
Tolerable: no change in dose Non tolerable: hold until < grade 1 -resume at same dose

Grade 3
Hold* until ≤ grade 2 -resume at 1 dose level lower if indicated

Grade 4
Hold* until ≤ grade 2 -resume at 1 dose level lower * Patients requiring a delay of > 4 weeks should discontinue protocol therapy Table 2

Dose delay and modification criteria for panitumumab-related adverse events
In the event of panitumumab-related adverse events patients should follow the dose interruption, resumption and reduction criteria stated in Table 2.
Note: dose modifications levels for panitumumab are stated in Table 3.

Starting dose
100% of original dose Level 1 Dose reduction 80% of original dose Level 2 Dose reduction 60% of original dose It is allowed, according to the Investigator's opinion, with holding panitumumab administration, up to a maximum of four weeks, for the following reasons: • Symptomatic skin-or nail-related toxicity requiring narcotics, systemic steroids, or felt to be intolerable by the subject (see Table 4) • Skin or nail infection requiring IV antibiotic or IV antifungal treatment • Any skin-or nail-related serious adverse event • Symptomatic hypomagnesaemia and/or hypocalcaemia that persists despite magnesium and/or calcium replacement (see Table 5   In the event of haematological and/or non-haematological toxicities patients should follow the dose interruption, resumption and reduction criteria stated in Table 6, Table 7, Table 8.
If the toxicities that require trifluridine / tipiracil dose reductions recur after dose reduction to 20 mg/m², trifluridine / tipiracil should be discontinued.
A maximum of three dose reduction(s) is permitted to a minimum dose of 20 mg/m² (total 40 mg/m²/day) in 5 mg/m² steps. Dose re-escalation is not permitted at any time.
Withhold Trifluridine-Tipiracil if any of these AE occurs: Resumption criteria a  Table 6

-Dose interruption and resumption criteria for Trifluridine-Tipiracil related AEs
Adverse events that require dose modifications:

Febrile neutropenia
Grade 4 neutropenia (<0.5 x 10 9 /L) or thrombocytopenia (<25 x 10 9 /L) that results in more than 1 week delay in start of next cycle Non-hematologic Grade 3 or Grade 4 adverse reaction (except for Grade 3 nausea and/or vomiting controlled by antiemetic therapy or diarrhea responsive to antidiarrheal medicinal products)
When resuming dosing, decrease the dose level by 5 mg/m²/dose from the previous dose level (

Criteria to resume treatment
Subjects may resume treatment with study drug when the drug-related AE(s) resolve to Grade ≤ 2 or baseline value, as per Table 2, with the exception of Trifluridine-Tipiracil toxicities, as   per Table 6, Table 7, Table8.
If the criteria to resume treatment are met, the subject should restart treatment at the next scheduled time-point per protocol.
If treatment is delayed >4 weeks, the subject must be permanently discontinued from study.
However, the patient can continue any treatment as per local standard practice and must be followed up with the study procedures.

Discontinuation criteria
Treatment with panitumumab should be permanently discontinued for the following reasons: Patients have the right to withdraw from the treatment or from the study at any time and irrespective of the reason. When applicable, patients should be informed of circumstances under which their participation may be terminated by the Investigator without their consent. The Investigator may withdraw patients from the study in the event of intercurrent illness, AEs, treatment failure after a prescribed procedure, lack of compliance with the study and/or study procedures (e.g., dosing instructions, study visits), or any reason where it is felt by the Investigator that it is in the best interest of the patient to be terminated from the study. Any administrative or other reasons for withdrawal must be documented and explained to the patient.
Any subject who definitively interrupts study treatment will be evaluated at the End-oftreatment Visit conducted 21 days (±7 days) after permanently stopping study treatment (see section 4.4.4).
In all cases, the reason for definitive interruption of study treatment mustbe entered in the electronic Case Report Form (eCRF) and in the subject's medical records. Patients who withdraw from the study will not be replaced. Only patients included in the study that have not started treatment with the first dose of drugs will be replaced.

4.3.3Concomitant Treatments
The patient must notify the investigational site about any new medications he/she takes after the start of the study drug. All medications (other than study drug) and significant non-drug If either value is above the therapeutic range, the anti-coagulant dose should be modified and the assessments should be repeated once weekly until the value is stable.
• Palliative radiotherapy may be given for control of pain or for other reasons without curative intent.
• Pre-emptive skin treatment regimen is mandatory, if there are not contraindications and it must be administered one day before the administration of the first panitumumab dose and continued through weeks 1 to 6. It consists of: -skin moisturizer applied to face, hands, feet, neck, back, and chest daily in the morning on rising; -sunscreen (PABA free, SPF ≥ 15, UVA and UVB protection) applied to exposed skin areas before going outdoors; -topical steroid (1% hydrocortisone cream) applied to face, hands, feet, neck, back, and chest at bedtime -doxycycline 100 mg twice daily. During the assumption of doxycycline, the patient must be advised to drink plenty of liquids to reduce the risk of esophageal irritation and ulceration; he/she must take doxycycline in upright position and must not lie down for an hour after taking the drug. The patient should not take iron supplements, multivitamins, calcium supplements, antacids, or laxatives within 2 hours before or after taking doxycycline. Please remember that the absorption of tetracyclines is reduced when taken with foods, especially those containing calcium.

Prohibited concomitant medications and treatments
• No other systemic anti-cancer therapy • Caution is required when using medicinal products that are human thymidine kinase substrates, e.g., zidovudine. Such medicinal products, if used concomitantly with Trifluridine-Tipiracil, may compete with the effector, Trifluridine, for activation via thymidine kinases. Therefore, when using antiviral medicinal products that are human thymidine kinase substrates, monitor for possible decreased efficacy of the antiviral medicinal product, and consider switching to an alternative antiviral medicinal product that is not a human thymidine kinase substrate, such as lamivudine, zalcitabine, didanosine and abacavir.

Schedule of Assessments and Procedures
All screening/baseline assessments must be performed as outlined in schedule assessment flow chart (see Tables 9) Eligibility for the study will be determined by the Investigator, from the mandatory screening/baseline assessments, performed during screening and according to the study inclusion/exclusion criteria.
First dosing of study drugs will be determined by the patient's eligibility and the laboratory assessments done prior to dosing.
Patients will be assessed for AEs at each clinical visit according to NCI CTC-AE v. 5.0 criteria and as necessary throughout the study.
Patients who discontinue study drug for any reason (e.g., AEs, etc.) other than disease progression will continue to be followed.
Progression of disease will be documented, as well as the initiation of another cancer therapy

Procedures for Enrolment of Eligible Patients
A patient who has fulfilled the entry criteria will be randomized and given an identifying number. Each identifying number will be unique to the patient for whom it is issued. A patient number will not be re-used if the patient leaves the study. Under no circumstances will patients who enroll in this study and have completed treatment as specified be permitted to re-enroll in the study. A Patient Enrolment and Identification Code List must be maintained by the Investigator.

Screening and Baseline Assessments
All screening/baseline evaluations must be performed within 28 days prior to randomization.
Patients who fulfill all the inclusion and none of the exclusion criteria will be accepted into the study. The following clinical assessments and procedures must be completed for all patients enrolled in this study at screening/baseline and during study visits. Screening procedures could be completed during multiple visits but must be completed within the specified timeframes.

Treatment assignment
After written informed consent has been obtained and eligibility established, each patient will be randomized as per Study Design (see Figure 1). Randomization should be performed within 3 days to C1D1. Note: procedures (haematology, biochemistry) have not to be repeated if performed as baseline (screening) within 7 days prior to randomization.
• Evaluation of tumor response by CT, or MRI eligibility scan (chest, abdomen, pelvis, and other having resulted positive during baseline staging) conforming to RECIST v1.1 must be performed every 8 weeks ± 7 days until PD on treatment. Tumor assessments should be performed on this schedule regardless of whether study treatment has been administered or held, and also if the patient is off treatment due to reason other than PD (i.e. refusal or unacceptable toxicity).
• Peripheral blood samples for exploratory biomarker studies every 8 weeks ± 7 days, the first day before drugs administration of a treatment cycle until PD.

Assessments at End of Treatment
The End-of-Treatment assessments should be performed no later than 21 days+/-7 days after patient's last dose of study medication. If the patient will be starting new anticancer therapy within the 21 days +/-7 days after the last dose of study medication, the withdrawal visit should be performed prior to the start of new anticancer therapy.

ECOG performance status
Haematology (

Follow-Up Assessments
All subjects who finish treatment, whichever the reason, will enter the follow-up. All subjects will be followed until death and data on subsequent treatment will be collected. Follow-up information on tumor status and vital status will be updated every 3 months until death. For patients with no progressive disease after terminating study treatment (i.e. treatment refusal, unacceptable toxicity), tumor assessments, blood samples for plasma biomarker analyses, will be performed every 8 weeks ± 7 days until PD If lost to follow-up, the Investigator should make every effort to contact the patient by telephone or by sending a registered letter to establish as completely as possible the reason for the withdrawal. A complete final evaluation at the time of the patient's withdrawal should be made with an explanation of why the patient is withdrawing from the study.

Collection of CT scans
It is required that CT scans or other relevant radiologic examinations used for staging and restaging procedures are collected and made available for eventual revision of response and time-to-progression definition.

RESPONSE EVALUATION
Response must be evaluated through repetition of the CT or MRI scan of chest, abdomen and pelvis every 8 weeks from treatment start. Response will be codified by the Investigator according to the RECIST (Response Evaluation Criteria In Solid Tumors) guidelines version 1.1, summarized below.

Measurability of tumor lesions
At the baseline evaluation, the lesions will be defined as follows:

measurable:
Lesions which can be accurately measured on at least one dimension (the longest diameter must be recorded) and found to be ≥10 mm with CT scan or ≥ 20 mm with conventional techniques Lymph node found to be ≥ 15 mm in short axis with CT scan.
Note: All tumor measurements must be recorded in millimeters (or decimal fractions of centimeters)

non-measurable:
Lesions that are measurable but small (largest Diameter<10 mm with CT scan or <20 mm with conventional techniques or pathological lymph nodes with ≥ 10 to <15 mm short axis).
Bone lesions, leptomeningeal disease, ascites, pleural/pericardial effusions, lymphangitis of skin or lung, and abdominal masses or organomegaly (that cannot be followed by CT or MRI).

Lesions that are located in previously irradiates areas
All measurements must be made using a centimeter rule or gauge. All the baseline evaluations must be performed as close to the treatment start date as possible, and in all cases no more than 4 weeks to randomization.

Identification of "target" and "non-target" lesions
All measurable lesions up to a maximum of 2 lesions per organ and 5 lesions in total, representative of all involved organs, should be identified as target lesions and recorded and measured at baseline assessment. The target lesions should be selected on the basis of their size (lesions with the longest diameter), trying to represent all the involved organs. In addition, target lesions should be those that lend themselves to reproducible repeated measurements. It may be the case that, on occasion, the largest lesion does not lend itself to reproducible measurement in which circumstance the next largest lesion which can be measured reproducibly should be selected. The sum of the baseline diameters (longest for non-nodal lesions, short axis for nodal lesions) of all target lesions will be calculated, reported in the eCRF, and used as reference for defining the objective response. All other lesions are identified as nontarget lesions and must also be recorded at baseline assessment. Measurement of these lesions is not required, but the presence, absence, or the eventual unequivocal progression of each of them must be noted during the follow-up, at each scheduled restaging

Evaluation of target lesion response
Complete response (CR): disappearance of all the target lesions. Any pathological lymph nodes (whether target or nontarget) must have reduction in short axis to <10mm.

Partial Response (PR):
reduction of at least 30% in the sum of diameters of the target lesions, compared to the baseline evaluation.

Progression (PD):
increase of at least 20% in the sum of diameters of target lesions and an absolute increase of at least 5 mm, compared to the lowest sum recorded since the start of the treatment, or the appearance of one or more new lesions.

Stable disease (SD):
neither a sufficient reduction to be defined as PR, nor a sufficient increase to be defined as PD

Complete Response (CR):
Disappearance of all non-target lesions. All lymph nodes must be non-pathological in size(<10 mm short axis)

Non Complete Response / Non Progression (CR/non-PD):
Persistence of one or more target lesions

Progression (PD):
Appearance of one or more new lesions or indisputable, clear progression of an existing non-target lesion.

Evaluation of best overall response
The best overall response is the best response recorded from the start of treatment until disease progression/recurrence (taking the lowest measurement recorded since the start of treatment as reference for the progression). An overall deterioration in the state of health leading to a suspension of the treatment without evidence of progression will be defined as a "symptomatic worsening". Patients who suspend treatment due to symptomatic worsening will be considered as non-responding

Reporting of results
All patients included in the study must be assessed for response to treatment. Each patient will be assigned one of the following categories: 1) complete response, 2) partial response, 3) stable disease, 4)progressive disease, 5) early death from malignant disease, 6) early death from toxicity, 7) early death because of other cause, or 8) unknown (not assessable, insufficient data).All patients will be included in the analysis of the response rate. Patients in response categories 4-8 will be considered as failing to respond to treatment.

Blood Sample Collection and analysis
Patients should provide written informed consent to obtain plasma blood samples (at least 20 mL in EDTA tubes) at screening, tumor assessment time points and End of Treatment.
Plasma samples will be stored at -80 °C at local sites and subsequently will be shipped to the Sponsor.

6.2Tumor Tissue Sample Collection
Tumor Tissue Sample will be collected at baseline and subsequently will be shipped to the Sponsor

Summary of the Safety Profile
Based on an analysis of mCRC clinical trial patients receiving panitumumab monotherapy and in

Hypersensitivity Reactions
Hypersensitivity reactions have been reported, including a fatal case of angioedema that occurred more than 24 hours after the infusion. Depending on the severity (eg, presence of bronchospasm, edema, angioedema, hypotension, need for parenteral medication, or anaphylaxis) and/or persistence of hypersensitivity reactions, permanently discontinue panitumumab.

Dermatologic and Soft Tissue Toxicity
Skin and subcutaneous tissue disorders, a pharmacologic effect observed with epidermal growth factor receptor (EGFR) inhibitors, were frequently reported (approximately 93% in patients across the monotherapy mCRC clinical trials [N = 1052]

Pulmonary Toxicity
Fatal and non-fatal cases of interstitial lung disease (ILD) have been observed in patients treated with EGFR inhibitors including panitumumab. In the event of acute onset or worsening of pulmonary symptoms, panitumumab therapy should be interrupted and a prompt investigation of these symptoms should occur. If ILD is confirmed, panitumumab should be permanently discontinued and the patient should be treated appropriately. In patients with a history of interstitial pneumonitis or pulmonary fibrosis or evidence of interstitial pneumonitis or pulmonary fibrosis, the benefits of therapy with panitumumab versus the risk of pulmonary complications must be carefully considered.

Electrolyte Disturbances/Monitoring
Progressively decreasing serum magnesium levels leading to severe hypomagnesemia have been observed in some patients. Patients should be monitored for hypomagnesemia and accompanying hypocalcemia prior to initiating panitumumab treatment, and periodically during panitumumab treatment and for up to 8 weeks after the completion of treatment. Magnesium repletion is recommended, as appropriate.
Other electrolyte disturbances, including hypokalemia, have also been observed. Repletion of these electrolytes is also recommended, as appropriate.

Myelosuppressive toxicities
In the RECOURSE trial, the incidence of Grade ≥3 neutropenia was 38% in patients treated with Trifluridine/Tipiracil, the incidence of febrile neutropenia was 4%. In the event of Grade 4 neutropenia (absolute neutrophil count [ANC] <0.5 x 10 9 /L) within a treatment cycle, the dose of Trifluridine/Tipiracil should be held until the ANC increases to ≥1.5 x 10 9 /L(see section 4.3.2; Table 6 -7). If the delay is longer than 1 week, the dose of Trifluridine/Tipiracil in the next cycle should be reduced by 5 mg/m2 per dose from the previous dose level. If febrile neutropenia occurs, the dose of Trifluridine/Tipiracil should be held until the episode of febrile neutropenia is completely resolved, and the drug dose in the next cycle should be reduced by 5 mg/m2 per dose from the previous dose level (see Table 8). Prophylactic administration of G-CSF is recommended to prevent the development of febrile neutropenia, according to current guidelines (J. Klastersky et al 2016, ESMO guidelines). In the RECOURSE study G-CSF support was used in 9.4% of patients

Anemia
Red blood cell transfusion is the recommended treatment for patients with symptomatic anemia due to myelosuppressive chemotherapy, and the use of transfusions should also be considered for asymptomatic patients with anemia who have underlying comorbidities.

Thrombocytopenia
For platelet counts <0.5 x 10 9 /L, the dose of Trifluridine/Tipiracil should be held until the platelet counts increase to ≥75 x 10 9 /L (see section 4.3.2; Table 6-Table 7). If the delay is longer than 1 week, the dose of Trifluridine/Tipiracil in the next cycle should be reduced by 5 mg/m 2 per dose from the previous dose level. Prophylactic platelet transfusions are recommended at a threshold platelet count of 10 x 10 9 /L for patients with solid tumors who have chemotherapy-induced thrombocytopenia.

Non-hematologic AEs
In the RECOURSE trial the Trifluridine/Tipiracil group had higher rates of Grade ≥3 nausea (2% vs. 1%), vomiting (2% vs. < 1%), and diarrhea (3% vs. < 1%). However, there were no clinically meaningful differences between the treatment groups in the percentage of patients with other non-hematologic AEs, including decreased appetite, stomatitis, and hand-foot syndrome. For Grade ≥3 non-hematologic AEs, the dose of Trifluridine/Tipiracil should be held until resolution of the AE to Grade 0 or 1 (see section 4.3.2; Table 6 -7). With the exception of Grade 3 nausea, vomiting, or diarrhea that is controlled by medication, the dose of Trifluridine/Tipiracil in the next cycle should be reduced by 5 mg/m2 per dose from the previous dose level for Grade ≥3 non-hematologic AEs (Table 3).

Clinical Adverse Events (AEs)
According to the International Conference of Harmonization (ICH), an AE is any untoward medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product and which does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign [including an abnormal laboratory finding], symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not considered related to the medicinal (investigational) product. Pre-existing conditions worsening during thestudy are to be reported as AEs.

Intensity
Intensity of all AEs will be graded according to the NCI CTCAE v.5.0 on a five-point scale (Grade 1 to 5) and reported in detail on the CRF.
AEs not listed on the CTCAE should be graded as follows: Grade 1: Mild Discomfort noticed but no disruption of normal daily activity Grade 2: Moderate Discomfort sufficient to reduce or affect daily activity; no treatment or medical intervention is indicated although this could improve the overall well-being or symptoms of the patient Grade 3: Severe Inability to work or perform normal daily activity; treatment or medical intervention is indicated in order to improve the overall wellbeing or symptoms; delaying the onset of treatment is not putting the survival of the patient at direct risk Grade 4: Life threatening/disabling. An immediate threat to life or leading to a permanent mental or physical conditions that prevents work or performing normal daily activities; treatment or medical intervention is required in order to maintain survival Grade 5: AE resulting in death

7.2.2Drug AE relationship Adverse (drug) reaction (ADR)
The causality relationship of study drug to the AE will be assessed by the Investigator as either: Yes or

No
If there is a reasonable suspected causal relationship to the study medication, i.e. there are facts (evidence) or arguments to suggest a causal relationship, drug-event relationship should be assessed as Yes.
The following criteria should be considered in order to assess the relationship as Yes: -Reasonable temporal association with drug administration -It may or may not have been produced by the patient's clinical state, environmental or toxic factors, or other modes of therapy administered to the patient -Known response pattern to suspected drug -Disappears or decreases on cessation or reduction in dose -Reappears on re-challenge -An adverse (drug) reaction (ADR) is a response to a medicinal product which is noxious and unintended. Response in this context means that a causal relationship between a medicinal product and an adverse event is at least a reasonable possibility. Adverse reactions may arise from use of the product within or outside the terms of the marketing authorization or from occupational exposure.
Conditions of use outside the marketing authorization include overdose, misuse, abuse, and medication errors.
The following criteria should be considered in order to assess the relationship as No: -It does not follow a reasonable temporal sequence from administration of the drug -It may readily have been produced by the patient's clinical state, environmental or toxic factors, or other modes of therapy administered to the patient -It does not follow a known pattern of response to the suspected drug -It does not reappear or worsen when the drug is re-administered

Serious Adverse Events (SAE)
A SAE is any experience that suggests a significant hazard, contraindication, side effect or precaution.
It is any AE that at any dose fulfills at least one of the following criteria: is fatal (results in death; NOTE: death is an outcome, not an event) is Life-Threatening (NOTE: the term "Life-Threatening" refers to an event in which the patient was at immediate risk of death at the time of the event; it does not refer to an event which could hypothetically have caused a death if it had been more severe).
requires in-patient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity; is a congenital anomaly/birth defect; is another Important Medical Event (any important adverse events/reactions that is not immediately life-threatening or do not result in death or hospitalization, but may jeopardize the subject or may require medically significant or requires intervention to prevent one or other of the outcomes listed above).
Examples of such events include, but are not limited to, intensive treatment in an emergency room or at home for allergic bronchospasm, blood dyscrasias or convulsions that do not result in hospitalization).
Note: The term sudden death should be used only when the cause is of a cardiac origin as per standard definition. The terms death and sudden death are clearly distinct and must not be used interchangeably.
The study will comply with all local regulatory requirements and adhere to the full requirements of the

ICH Guideline for Clinical Safety Data Management, Definitions and Standards for Expedited
Reporting.

Serious adverse drug reaction ( SADR)
A Serious adverse drug reaction (SADR) is an adverse reaction which results in death, is lifethreatening, requires in-patient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability or incapacity, or is a congenital anomaly/birth defect.
Medical and scientific judgment should be exercised in deciding whether other situations should be considered serious adverse reactions, such as important medical events that might not be immediately life threatening or result in death or hospitalization but might jeopardize the patient or might require intervention to prevent one of the other outcomes listed above.
Examples of such events are intensive treatment in an emergency room or at home for allergic bronchospasm, blood dyscrasias, or convulsions that do not result in hospitalization, or development of dependency or abuse.
Any suspected transmission via a medicinal product of an infectious agent is also considered a serious adverse reaction.

Special situations:
Overdose An overdose is a significant variation above the recommended/scheduled dosage for a product. In this current trial an overdose of the study drugs is any dose higher than the dose specified in the Sections There is no known antidote available in case of Trifluridine/Tipiracil overdose. Overdose should be managed aggressively with close monitoring and administration of prophylactic and symptomatic therapies to prevent or correct potential side effects.

Abuse, misuse, occupational exposure
Misuse refers to situations where the medicinal product is intentionally and inappropriately used not in accordance with the authorized product information.
Abuse corresponds to the persistent or sporadic, intentional excessive use of a medicinal product, which is accompanied by harmful physical or psychological effects.
Occupational exposure refers to the exposure to a medicinal product, as a result of one's professional or non-professional occupation.

Medication errors
A medication error for this study is defined as any accidental incorrect administration of a medicinal product. The error may be related to the administration of a wrong medication, nature of the medication, route of administration, dosage or frequency of the treatment as specified in this protocol (including omission of one or more administrations).
-Medication errors with concomitant medication treatment will not be recorded in the CRF unless they result in an AE.
-Medication errors with the study medication that result in an AE will be captured as an AE in the CRF.
-Medication errors with the study medication that result in the omission of an administration, an incorrect dose (relative to that specified in this protocol), or the administration of more than the prescribed dose will be identified through the recording of study drug accountability data in the CRF.
-Medication errors with the study medication resulting in an overdose, incorrect route of administration, or administration with the incorrect study drug will be reported

Planned Hospitalization
A hospitalization planned by the subject prior to signing the informed consent form (ICF) is considered a therapeutic intervention and not the result of a new SAE and should be recorded as medical history. If the planned hospitalization or procedure is executed as planned, the record in the subject's medical history is considered complete. However, if the event/condition worsens during the trial, it must be reported as an AE.

Treatment and Follow-up of AEs
Please see section 7.1. for general guidelines for management of specific toxicities.
A general principle is that differential diagnoses should be diligently evaluated according to standard medical practice. Non-inflammatory etiologies should be considered and appropriately treated.
The treatment and follow up of all the AEs should follow the indication provided below.
For Related AEs, follow until one of the following occurs: -Resolved or improved to baseline; -Relationship is reassessed as unrelated; -Death; -Investigator confirms that no further improvement can be expected; -Clinical or safety data will no longer be collected, or final database closure.
For Unrelated severe or life-threatening AEs, follow until one of the following occurs: -Resolved or improved to baseline; -Severity improved to Grade 2; -Death; -Investigator confirms that no further improvement can be expected; -Clinical or safety data will no longer be collected, or final database closure.
The final outcome of each AE must be recorded on the CRF.

Laboratory Test abnormalities
Laboratory test results will be recorded on the laboratory results form of the eCRF, or appear on electronically produced laboratory reports submitted directly from the central laboratory, if applicable.
Any treatment-emergent abnormal laboratory result that is clinically significant, i.e., meeting one or more of the following conditions, should be recorded as a single diagnosis on the AE page in the eCRF:

Accompanied by clinical symptoms
Leading to a change in study medication (e.g. dose modification, interruption or permanent discontinuation) Requiring a change in concomitant therapy (e.g. addition of, interruption of, discontinuation of, or any other change in a concomitant medication, therapy or treatment) This applies to any protocol and non-protocol specified safety and efficacy laboratory result from tests performed after the first dose of study medication, which falls outside the laboratory reference range and meets the clinical significance criteria.

Follow-up of Abnormal Laboratory Test Values
In the event of medically significant unexplained abnormal laboratory test values, the tests should be repeated and followed up until they have returned to the normal range and/or an adequate explanation of the abnormality is found. If a clear explanation is established it should be recorded on the eCRF.

Reporting of AEs
Information about all adverse events, whether volunteered by the patient, discovered by Investigator questioning, or detected through physical examination, laboratory test or other means, will be collected on the Adverse Event CRF page, documented in the patient's medical records, and followed as appropriate.
The NCI CTC-AE (Version 5.0) will be used to evaluate the clinical safety of the treatment in this study.
Patients will be assessed for AEs at each clinical visit and as necessary throughout the study.

Reporting of SAEs (immediately reportable)
Any clinical AE, or abnormal laboratory test value assessed as serious (as defined above), pregnancy case, occurred during the course of this study from the enrolment visit (start of study screening procedures), including long term follow-up, must be reported to Sponsor and within one working day of the Investigator becoming aware of the event (expedited reporting). In addition, report of Adverse Events will be done, according to current local law, to local Health Authorities.
From the first administration of study drugs, all SAEs must be reported. Related SAEs MUST be collected and reported regardless of the time elapsed from the last study drugs administration, even if the study has been closed. Suspected Unexpected Serious Adverse Reactions (SUSARs) are reported to Investigators at each site and associated IRB/IEC when the following conditions occur: The event must be a SAE There must be a certain probability that the event is an adverse reaction from the administered drugs The adverse reaction must be unexpected, that is to say, not foreseen in the Investigator's Brochure of study drugs. When all patients at a particular site are off treatment as defined by the protocol: -only individual SUSAR reports originating in that particular trial will be forwarded to the site and associated Insitutional Review Board (IRB) / Independent Ethics Committee (IEC) on an expedited basis -individual SUSARs considered to be a significant safety issue and/or which result in recommending a change to the ICF, will be reported in an expedited manner to all Investigators and IRBs/IECs SUSAR reports originating from other trials using the same study drugs will be provided as six monthly SUSAR Reports to Investigators and IRBs/IECs where long-term follow-up studies are carried out, unless they are considered significant Unrelated SAEs must be collected and reported during the study and for up to five years after the last dose of study medication and every 3 months for long-term follow up.
This study adheres to the definition and reporting requirements of ICH Guideline for Clinical Safety Data Management, Definitions and Standards for Expedited Reporting.

Pregnancy
Female patients must be instructed immediately inform the investigator if they become pregnant during the study. The investigator should report all pregnancies within 24 hours to the Sponsor and, using the Clinical Trial Pregnancy Reporting Form. The investigator should counsel the patient, discuss the risks of continuing with the pregnancy and the possible effects on the fetus.
Pregnancies occurring up to 6 months after the completion of the study medication must also be reported to the Investigator. Pregnancies occurring in the partner of a male patient participating in the study should be reported to the investigator and the sponsor. The partner should be counseled, the risks of continuing the pregnancy discussed, as well as the possible effects on the fetus. Monitoring of the patient should continue until conclusion of the pregnancy.

Safety data exchange requirement
Investigators should forward all SAEs and SUSARS to the Sponsor as soon as possible, but no later than 1 business day; pregnancy and lactation reports must be sent within 7days.
The Sponsor will provide Amgen with a copy of any SAE report received by the Investigators.
Furthermore a copy of SUSARS must be sent to Amgen at the time of regulatory submission.
The Sponsor will also provide Amgen with a yearly Safety Report and with a copy of any other communication. Aggregate reports, containing safety data generated during the course of the study are to be sent to the Regulatory Authorities and to Amgen by the sponsor.
The final study report to be sent to Amgen no later than one calendar year from study completion.
The Sponsor will provide Servier with a copy of any SAE report received by the Investigators.
Furthermore, a copy of SUSARS must be sent to Servier at the time of regulatory submission.
The Sponsor will also provide Servier with a yearly Safety Report and with a copy of any other communication. Aggregate reports, containing safety data generated during the course of the study are to be sent to the Regulatory Authorities and to Servier by the sponsor The final study report to be sent to Servier no later than one calendar year from study completion

Sample size calculation
This is a randomized phase II, open label, two arm study, evaluating the efficacy of Trifluridine-Tipiracil in combination with panitumumab as third line therapy, after a first line containing an anti-EGFR agent panitumumab or cetuximab.
The study is designed to have 80% power to detect a hazard ratio for progression of 0.56 (a 44% reduction in risk) in the panitumumab+ Trifluridine-Tipiracil group as compared with the Trifluridine-Tipiracil group, with a two-sided type I error rate of 0.1. Given the treatment assignment ratio of 1:1 (Trifluridine-Tipiracil: panitumumab + Trifluridine-Tipiracil), we calculate that at least 74 events (progression) in 112 subjects (56 in the control group and 56 in the treatment group) would be required for the primary analysis.

Analysis Populations
Baseline is defined as the last valid visit or day before the treatment start. The following populations are defined for this study:

All Enrolled Set
All screened subjects who have been enrolled.

Intention To Treat (ITT) set
All enrolled patients that start the treatment will be considered the Intention-To-Treat population (ITT).

Safety Set
The subset of patient of the ITT population receiving at least one dose of the study medication will define the Safety Population (SP).

Statistical analysis
The median period of follow-up will be calculated for the entire study cohort according to the reverse Kaplan-Meier method. Distributions of time-to-event variables will be estimated with the use of the Kaplan-Meier product-limit method. The stratified log-rank test will be used as the primary analysis for comparison of treatment groups. Cox proportional-hazards modeling will be also performed as supportive analyses. Subgroup analyses of progression-free survival will be performed by means of an interaction test to determine the consistency of the treatment effect according to key baseline characteristics. Overall survival will be analyzed with the same methods used for the analysis of progression-free survival.
The objective response rate and the incidence of adverse events in the different groups will be compared with the use of the chi-square test for heterogeneity.
All statistical tests will be two-sided, and P values of 0.05 or less will be considered to indicate statistical significance. Odds ratios and 95% confidence intervals will be estimated with a logistic-regression model, and hazard ratios and 95% confidence intervals will be estimated with a Cox proportional hazards model.

Data handling
ORR and its association with prognostic factors will be investigated using the chi-square test and a logistic regression model will be used to study interrelationship among factors.
Safety and tolerability will be assessed in terms of AEs, laboratory data, ECG data, vital signs and weight, which will be collected for all patients. AEs (both in terms of MedDRA preferred terms and CTCAE grade), laboratory data, ECG data, vital signs data and weight will be listed individually by the patient and summarized by treatment received. Worst grade for each toxicity will be reported according to their relationship to study drugs. Treatment discontinuation due to AEs will also be described according to the treatment exposure.
Treatment duration, dose intensity, dose modification and discontinuation will be analyzed in each arm.
Due to the small sample size, statistical analysis of biomarkers data will be conducted with the aim of hypothesis generation. A complete description of data will be done. For biomarkers that might change over time as a consequence of treatment, levels before and after treatment will be compared with appropriate statistical tests, based on the type of data. Repeated measurement ANOVA model will be used to test differences along time.
Correlation with Outcomes will be evaluated with univariate regression models. P values ≤0.05 will be considered significant, and no adjustment is planned for multiple comparisons due to the exploratory nature of the analysis of the secondary endpoints.

Data confidentiality
Information about study subjects will be kept confidential and managed under the applicable laws and regulations. The data collection system for this study uses built-in security features to encrypt all data for transmission in both directions, preventing unauthorized access to confidential participant information. Access to the system will be controlled by a sequence of individually assigned user identification codes and passwords, made available only to authorized personnel who have completed prerequisite training.

Site monitoring
Before study initiation, at a site initiation visit or at an investigator's meeting, Sponsor personnel will review the protocol and CRFs with the investigators and their staff. During the study, the field monitor will visit the site regularly to check the completeness of patient records, the accuracy of entries on the CRFs, the adherence to the protocol to Good Clinical Practice, the progress of enrolment, and to ensure that study treatment is being stored, dispensed, and accounted according to specifications. Key study personnel must be available to assist the field monitor during these visits. The investigator must maintain source documents for each patient in the study, consisting of case and visit notes (hospital or clinic medical records) containing demographic and medical information, laboratory data, electrocardiograms and the results of any other tests or assessments. All information recorded on CRFs must be traceable to source documents in the patient's file. The investigator must also keep the original signed informed consent form (a signed copy is given to the patient). The investigator must give the monitor access to all relevant source documents to confirm their consistency with the CRF entries. The Sponsor monitoring standards require full verification for the presence of informed consent, adherence to the inclusion/exclusion criteria and documentation of SAEs.

Data collection
This study will use an Electronic Data Capture (EDC) system (eClinical platform provided by Clinical Research Technology). The designated investigator staff will enter the data required by the protocol into the Electronic Case Report Forms (eCRF). The eCRFs have been built using eClinical platform provided by Clinical Research Technology, a fully validated secure web-enabled software that conforms to Food and Drug Administration (FDA) requirements. Investigator site staff will not be given access to the EDC system until they have been trained. Automatic validation programs check for data discrepancies in the eCRFs allow modification or verification of the entered data by the investigator staff. The Principal Investigator is responsible for assuring that the data entered into eCRF is complete, accurate, and that entry and updates are performed in a timely manner.

Database management and quality control
The Sponsor personnel (or designated contract research organization [CRO]) will review the data entered by investigational staff for completeness and accuracy. Electronic data queries stating the nature of the problem and requesting clarification will be created for discrepancies and missing values and sent to the investigational site via the EDC system. Designated investigator site staff is required to respond promptly to queries and to make any necessary changes to the data. Concomitant treatments entered into the database will be coded using the WHO Drug Reference List, which employs the Anatomical Therapeutic Chemical classification system. Medical history/current medical conditions and adverse events will be coded using the Medical dictionary for regulatory activities (MedDRA) terminology. The occurrence of any protocol violations will be determined. After the data have been verified to be complete and accurate, the database will be declared locked. Authorization is required prior to making any database changes to locked data, by joint written agreement between the Biostatistics and Data Management and the Sponsor.

Responsibilities of the investigator and IEC
The protocol and the proposed informed consent form must be reviewed and approved by Independent Ethics Committee (IEC) of all participating centers before study start.

Informed consent procedures
Eligible patients may only be included in the study after providing written (witnessed, where required by law or regulation), IEC-approved informed. Informed consent must be obtained before conducting any study-specific procedures (i.e. all of the procedures described in the protocol). The process of obtaining informed consent should be documented in the patient source documents. The date when a subject's Informed Consent was actually obtained will be captured in their CRFs.

Publication of study protocol and results
The key design elements of this protocol will be posted in the publicly accessible database clinicaltrialsregister.eu. The Investigators assure that results of this study will be submitted for publication and reported in scientific meetings.

Study documentation, record keeping and retention of documents
Each participating site will maintain appropriate medical and research records for this trial, in compliance with Section 4.9 of the ICH E6 GCP, and regulatory and institutional requirements for the protection of confidentiality of subjects. Each site will permit authorized representatives of the sponsor and regulatory agencies to examine (and when required by applicable law, to copy) clinical records for the purposes of quality assurance reviews, audits and evaluation of the study safety and progress. Source data are all information, original records of clinical findings, observations, or other activities in a clinical trial necessary for the reconstruction and evaluation of the trial. Examples of these original documents and data records include, but are not limited to, hospital records, clinical and office charts, laboratory notes, memoranda, subjects' diaries or evaluation checklists, pharmacy dispensing records, recorded data from automated instruments, copies or transcriptions certified after verification as being accurate and complete, microfiches, photographic negatives, microfilm or magnetic media, x-rays, and subject files and records kept at the pharmacy, at the laboratories, and medico-technical departments involved in the clinical trial. Data collection is the responsibility of the clinical trial staff at the site under the supervision of the site Principal Investigator. The study CRF is the primary data collection instrument for the study. The investigator should ensure the accuracy, completeness, legibility, and timeliness of the data reported in the CRFs and all other required reports. Data reported on the CRF, that are derived from source documents, should be consistent with the source documents or the discrepancies should be explained. All data requested on the CRF must be recorded. Any missing data must be explained. For electronic CRFs an audit trail will be maintained by the system. The investigator/institution should maintain the trial documents as specified in Essential Documents for the Conduct of a Clinical Trial (ICH E6 Section 8) and as required by applicable regulations and/or guidelines. The investigator/institution should take measures to prevent accidental or premature destruction of these documents. Essential documents (written and electronic) should be retained for a period of not less than seven (7) years from the completion of the Clinical Trial unless Sponsor provides written permission to dispose of them or, requires their retention for an additional period of time because of applicable laws, regulations and/or guidelines

Confidentiality of study documents and patient records
The investigator must ensure anonymity of the patients; patients must not be identified by names in any documents submitted to the Sponsor. However, the Sponsor may have access to source data. Signed informed consent forms and patient enrolment log must be kept strictly confidential to enable patient identification at the site.

Audits and inspections
Source data/documents must be available to inspections by the Sponsor or designee or Health Authorities.

Financial disclosures
Financial disclosures should be provided by study personnel who is directly involved in the treatment or evaluation of patients at the site -prior to study start.

PROTOCOL ADHERENCE
Investigators ascertain they will apply due diligence to avoid protocol deviations. Under no circumstances should the investigator contact the Sponsor or its delegates, if any, monitoring the study to request approval of a protocol deviation, as no authorized deviations are permitted. If the investigator feels a protocol deviation would improve the conduct of the study this must be considered a protocol amendment, and unless such an amendment is agreed upon by the Sponsor and approved by the IEC it cannot be implemented.

Amendments to the protocol
Any change or addition to the protocol can only be made in a written protocol amendment that must be approved by the Sponsor, Health Authorities where required, and the IEC. Only amendments that are required for patient safety may be implemented prior to IEC approval. Notwithstanding the need for approval of formal protocol amendments, the investigator is expected to take any immediate action required for the safety of any patient included in this study, even if this action represents a deviation from the protocol.

ADMINISTRATIVE ASPECTS
The study is a non-profit investigator initiated trial not sponsored by the pharmaceutical company which produce the drug used in the trial.
The promoter will provide an insurance policy to cover possible damages caused to patients participating in the trial.
Study protocol, patient information and informed consent will be submitted to Independent Ethical Committees and will only be started after their approval. Independent Ethical Committees will be periodically informed of study progress, safety and planned or premature end of the study.

Formulation, Packaging and Labelling
Study drug packaging will bear a label with the identification required by local law, the protocol number, drug identification and dosage.
Drugs will be administered open label. Drugs will be required to be labelled as per local SOPs and regulations.
Medication labels will be in the local language and comply with the legal requirements of each country in which the study will be conducted.

Accountability, assessment of compliance and destruction of the drugs
Study treatments must be received by designated personnel at the study site, handled and stored safely and properly, and kept in a secured location to which only the Investigator and designated site personnel have access.
Upon receipt, the study drugs should be stored according to the instructions specified on the drug labels and Investigator's Brochure for drugs (Panitumumab and Trifludine-Tipiracil). Study medication is to be stored in a secure locked area while under the responsibility of the Investigator. Receipt and dispensing of study medication must be recorded by an authorized person at the Investigator's site.
Any unused study drugs can only be destroyed after being inspected and reconciled by the responsible Study Monitor unless study drug containers must be immediately destroyed as required for safety, or to meet local regulations (e.g., cytotoxics or biologics).
On-site destruction is allowed provided the following minimal standards are met: On-site disposal practices must not expose humans to risks from the drug.
On-site disposal practices and procedures are in agreement with applicable laws and regulations, including any special requirements for controlled or hazardous substances.
Written procedures for on-site disposal are available and followed. The procedures must be filed with the site's SOPs and a copy provided to the study sponsor upon request.
Records are maintained that allow for traceability of each container, including the date disposed of, quantity disposed, and identification of the person disposing the containers. The method of disposal, i.e., incinerator, licensed sanitary landfill, or licensed waste disposal vendor must be documented.
Accountability and disposal records are complete, updated, and available for the Monitor to review throughout the clinical trial period.
If conditions for destruction cannot be met the responsible Study Monitor will make arrangements for return of study drug.
It is the investigator's responsibility to arrange for disposal of all empty containers, provided that procedures for proper disposal have been established according to applicable state, local, and institutional guidelines and procedures, and provided that appropriate records of disposal are kept.