What: Biogen (NASDAQ:BIIB) is down 12% at 1:15 p.m. EDT Tuesday after the biotech reported that opicinumab, one of its most lucrative pipeline drugs, failed a phase 2 clinical trial.
So what: Opicinumab, which used to be called anti-LINGO, was being tested in patients with the relapsing forms of multiple sclerosis. The drug targets LINGO-1, a protein that negatively regulates the myelin sheath that covers nerves that is damaged in multiple sclerosis patients. By inhibiting LINGO-1, removing the negative regulator, Biogen hoped to promote myelin growth and potentially reverse the disease progression; current treatments only slow progression of the disease.
Unfortunately, the drug doesn't appear to be working. The clinical trial, dubbed SYNERGY, failed to meet its primary endpoint that measured movement and cognition and its secondary endpoint of slowing disability progression.
No details were reported, but Biogen did note that there was "evidence of a clinical effect with a complex, unexpected dose-response," which means the drug looked like it was working at one -- or potentially more -- of the four doses tested, but not the ones above or below it. That can happen with some drugs when the highest dose is doing more harm than good, but it's also possible that the "evidence of a clinical effect" is just noise due to a relatively small data set.
Now what: It's not unexpected for this clinical trial to give mixed results considering opicinumab's history. A previous trial, called RENEW, in acute optic neuritis, which affects myelin in the eye nerves, showed that the time it takes for the signal to travel between the retina and the visual cortex in the back of the brain was faster in patients receiving opicinumab compared to placebo, but there wasn't an increase in the thickness of the optic nerve neurons and axons nor an increase in visual function.
Biogen plans to analyze the data more before deciding what to do next. Investors might get a look at the data at the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) annual meeting in the mid-September.
Brian Orelli has no position in any stocks mentioned. The Motley Fool recommends Biogen. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.