Tests for New Cancer Drugs Not Reliable Enough, Doctors Say

“Drugmakers including Bristol-Myers Squibb Co and Merck & Co are testing which patients will most benefit from new cancer treatments based on a protein found in their tumors, but that guide, known as a biomarker, may be too unreliable, researchers and health experts said.

“Bristol’s Opdivo and Merck’s Keytruda are both therapies designed to block a protein known as Programmed Death receptor (PD-1) that tumors use to evade the body’s natural defenses. Competitors Roche Holding, AstraZeneca and Pfizer also have similar drugs in an earlier stage of development. The drugmakers are conducting clinical trials that test patient tumors for a related protein called PD-L1.

“The new drugs are mainly aimed at patients with so-called solid tumors suffering from diseases including lung cancer and liver cancer. Lung cancer, the most common type, claims 1.8 million new cases each year worldwide. Sales of drugs to block PD-1 could reach $33 billion a year by 2022, according to Morningstar.”