UPDATED: Biogen Idec's remyelination drug raises hopes--and fears--in PhII

Biogen Idec ($BIIB) highlighted positive data from its mid-stage study of anti-LINGO-1, a closely watched drug that raises the potential for spurring remyelination--repairing the damage done by diseases like multiple sclerosis. But a careful second look at the results also underscores just how challenging this development program is for Biogen Idec, raising doubts about the true clinical significance of the results that quickly eliminated a spike in the company's share price.

This first of two Phase II studies in the program was for acute optic neuritis. Investigators for Biogen Idec said that their drug hit the primary goal: improving the time it takes for a signal to shoot from the retina to the visual cortex. 

But the drug also failed some key hurdles in the study, including its secondary endpoints, which involved a look at the change in thickness of the retinal layers, or optic nerve neurons and axons. In addition, investigators noted that if you included what's called the intent-to-treat (ITT) group, adding back in the patients who dropped out of the small study, anti-LINGO-1 did not hit the primary endpoint. ITT is the gold standard in this field, and quite a few analysts were quick to pick up on the implications.

"BIIB announced top line data for the RENEW trial of the anti-LINGO MAb BIIB033 that the company called 'positive' and which we can't absolutely disagree with, but we think could be considered equivocal by many," noted Leerink's Joseph Schwartz. 

Shares of Biogen spiked early as investors reacted to the news, but quickly settled back and then slipped into the red this morning.

Acute optic neuritis--or AON--was the first of two mid-stage challenges that Biogen Idec set up for itself as the company probed for solid human data to either back up or disprove the notion that this therapy could repair the harm done by demyelination--damage done to the myelin sheath of axons needed to guard neurons. Myelin is essential to the proper function of the central nervous system and a big focus at Biogen Idec, which has specialized in multiple sclerosis for years.

In this study the investigators tracked a 34% improvement in the recovery of optic nerve latency among the patients who finished the study (per protocol). The next big step will come when Biogen Idec's Phase II study for MS reads out in 2016. And despite the troubling missteps in the first Phase II, Biogen Idec believes it has plenty to be encouraged about as they ponder a pivotal program.

Alfred Sandrock

"We believe the RENEW results are encouraging, as this is the first clinical trial to provide evidence of biological repair in the central nervous system (CNS) by facilitating remyelination following an acute inflammatory injury," said Dr. Alfred Sandrock, group senior vice president and chief medical officer at Biogen Idec. "We look forward to the SYNERGY results in 2016 to further advance our understanding of this molecule in MS, including a full dose response. The totality of the data from the two Phase II studies may provide us with a clearer understanding of anti-LINGO-1's clinical potential."

Biogen Idec has scored a series of successes in the clinic in recent years, standing out as one of the most successful businesses in the industry. It's built much of its rep around slowing the progression of MS. This new program, though, would be a step toward reversing demyelination diseases, which would be a radical step forward.

- here's the release

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