Barrett Rollins, MD, PhD, chief scientific officer at the Dana-Farber Cancer Institute, tells an anecdote to illustrate the promise of “precision medicine.” A 35-year-old patient at Dana-Farber was dying of myeloid sarcoma, a rare tumor consisting of a solid collection of leukemic cells outside of the bone marrow. Although the man was about to enter hospice care, he consented to having his tumor’s genome sequenced.
Unexpectedly, sequencing revealed a mutation in a platelet-derived growth factor receptor gene, giving rise to a constitutively active kinase targeted by the kinase inhibitor imatinib mesylate, marketed as Gleevec. Myeloid sarcoma is not among Gleevec’s indications, but the man’s tumor shrank after he began taking the pill. Months later, he is still alive, no longer a candidate for hospice care, Rollins said.