TR: What makes Alzheimer’s such a difficult disease to target?
DM: Alzheimer’s disease progresses slowly and insidiously. By the time you see symptoms, that individual already has significant impairments. So we also have a big effort to identify biomarkers. (See “A Blood Test for Alzheimer’s?”) So we want to identify things that progress with the disease but change more quickly and are less variable. Having these markers will also allow shorter clinical trials.
We are also starting to look at markers for schizophrenia, which probably has several different pathologies. We want to understand who has what and use those markers to select interventions.
TR: Tell me about some of Merck’s drug candidates that are nearing approval.
DM: We have a novel migraine treatment in phase III clinical trials. Migraines are usually treated with tryptans, which are vasoconstrictors. While we don’t know exactly how this compound works, it does not act through this mechanism. In phase II clinical trials, it was shown to be very effective at aborting migraine attacks.
We are also testing a new ophthalmology treatment–a helical intraocular implant device. Right now, if you want to deliver drugs locally to the eye, you must give multiple injections. This device is coated with drugs and can be implanted into the eye, reducing the frequency of invasive procedures. We are currently testing it for diabetic macular edema, but we ultimately plan to use it to deliver novel compounds we are developing for age-related macular degeneration. The benefit is that we can use it to deliver drugs that might be problematic in the body but are okay if delivered in small amounts locally.