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July 5, 1985

The LD50

Author Affiliations

Pharmaceutical Manufacturers Association Washington, DC

JAMA. 1985;254(1):56. doi:10.1001/jama.1985.03360010062020

To the Editor.—  In his recent letter to the editor, Dr Hubbard failed to cite important actions by the Pharmaceutical Manufacturers Association (PMA) to bring about change in use of the median lethal dose (LD50) test. Our position paper,1 approved by the PMA Board of Directors in 1982, helped precipitate the Food and Drug Administration LD50 Conference mentioned in Dr Hubbard's letter.It is the PMA's position that, although there is no adequate substitute for acute toxicity studies involving the use of laboratory animals, a review of the utility of the precise LD50 test reveals that neither the toxicologist nor the clinical pharmacologist needs a precise LD50 value. Carefully controlled and professionally performed acute experiments can be conducted that require fewer animals and yet are more meaningful and relevant to the introduction of therapeutic agents than the LD50 test. Regulatory requirements should accommodate this