A capsule of good gut bacteria cuts bloodstream infections by 77% after stem-cell transplants

For people receiving a donor stem-cell transplant to treat blood cancer, one of the biggest dangers is not the cancer itself — it is infection. The treatment wipes out the gut's healthy bacteria, and harmful germs can then slip through the gut wall into the blood. SER-155, a capsule of carefully grown helpful bacteria developed by Seres Therapeutics in Cambridge, Massachusetts, was designed to rebuild that defence. In a Phase 1b trial whose results were published today in Nature Medicine, bloodstream infections struck 10% of patients who took SER-155, compared with 42.9% of those on a placebo — a 77% relative reduction. Patients on SER-155 also needed antibiotics for far fewer days (9.2 on average, against 21.1), and the treatment was generally well tolerated, with no serious side effects blamed on it. The US Food and Drug Administration has already given it Breakthrough Therapy status, and a larger Phase 2 trial is ready to go once funding is secured.

SDG 3 · Good health and well-being — Mechanism: tech innovation