Another next big thing could be in trouble

A reductively brief history of immuno-oncology could go like this: A handful of drugs worked better than anyone had expected, which inflated expectations for the next generation, which has largely been a disappointment.

In that context we find CD47, the so-called "don't eat me" protein that cancer cells use to skirt the attention of the immune system. The problem is that drugs targeting CD47 have had a rough go in 2018. Last night, Surface Oncology disclosed a "significant reduction of the investment in and scope of" its CD47 program after running into some alarming toxicities.

That follows Celgene's October decision to terminate a clinical trial of its own CD47 drug, and it resurrects some longstanding concerns about the underlying science.

Researchers have cautioned that preclinical studies may have overstated the cancer-killing benefits of blocking CD47. And, on the safety side, red blood cells use CD47 to go about their business without meddling from the immune system, which means blocking it could have dangerous side effects.