One Alzheimer's compound recently died off in the clinic - Bristol-Myers Squibb's avagacestat, a gamma-secretase inhibitor, has been pulled from trials. The compound "did not establish a profile that supported advancement" to Phase III, says the company. Gamma-secretase has been a troubled area for some time, highlighted by the complete failure of Lilly's semagacestat. I wondered, when that one cratered, what they were thinking at BMS, and now we know.
But Merck is getting all the attention in Alzheimer's today. They've announced that their beta-secretase inhibitor, MK-8931, is moving into Phase III, and the headlines are. . .well, they're mostly just not realistic. "Hope for Alzheimer's", "Merck Becomes Bigger Alzheimer's Player", and so on. My two (least) favorites are "Merck Races to Beat Lilly Debut" and "Effective Alzheimer's Drug May Be Just Three Years Away." Let me throw the bucket of cold water here: that first headline is extremely unlikely, and the second one is insane.
As I've said here several times, I don't think that there's going to be any big Lilly debut into Alzheimer's therapy with their lead antibody candidate, solanezumab. (And if there is, we might regret it). The company does have a beta-secretase (BACE) inhibitor, but that's not what these folks are talking about. And looking at Merck's compound, you really have to wonder if there's ever going to be one there, either. I like Fierce Biotech's headline a lot better: "Merck Ignores Red Flags and Throws Dice on PhII/III Alzheimer's Gamble". That, unfortunately, is a more realistic appraisal.
It's interesting, though, that Merck is testing this approach in a patient population that includes patients with moderate cases. After solanezumab and bapineuzumab appears to have hit that target without any clear signal that they had improved symptoms for patients with more fully developed cases, there has been a growing move to shift R&D into earlier-stage patients, whose brains have not already been seriously damaged by the disease. Merck is likely to face growing skepticism that it can succeed with the amyloid hypothesis when tackling the same population that hasn't delivered positive data.
And BACE has been a rough place to work in over the years. The literature is littered with oddities, since finding a potent compound that will also be selective and get into the brain has been extremely difficult. I actually applaud Merck for having the nerve to try this, but it really is a big roll of the dice, and there's no use pretending otherwise. I wish that the headlines would get that across, as part of a campaign for a more realistic idea of what drug discovery is actually like.