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more side effects than PGAs and typically require more than one dose per day. Aerie said in its S-1, for instance, that despite their limitations, non-PGA eye drops account for half the total glaucoma prescriptions filled in the U.S. and Europe.
Both Inotek and Aerie are targeting the trabecular meshwork with different approaches. Inotek’s experimental drug, trabodenoson, is supposed to spur enzymes within the trabecular meshwork to clear out the proteins that are clogging the drain, so to speak. Aerie’s drug candidate, AR-13324, is supposed to block two targets—one of which, the rho kinase, is implicated in fluid drainage.
“It’s good for the area that there are a couple of approaches being progressed,” McVicar says.
Even so, he contends that a few things separate Inotek from Aerie. First, he says, Inotek still thinks trabodenoson has a chance to be a monotherapy for glaucoma—something that would compete directly with PGAs and work by itself. Second, McVicar argues that AR-13324, as a monotherapy, appears to have a “mechanism linked side effect,” in that the more the dose has been increased in trials, the more patients have experienced hyperemia, or redness in the eyes. This, McVicar says, is why Aerie has changed the drug’s mechanism of action to hit two targets, rather than just the rho kinase alone.
Aerie, for its part, said in its S-1 that this effect has been “mild,” and that it’s a “common tolerability finding” associated with the most widely prescribed glaucoma drugs. Still, McVicar says this could give Inotek a leg up.
“It’s a little more difficult for them to say [they] can provide as much efficacy as [PGAs] because they may have to increase a dose too high, and that dose may be untenable,” he says.
That being said, Aerie’s drug has been dosed in patients once a day, while trabodenoson hasn’t. Though Inotek has claimed that trabodenoson is showing signs that it works better the longer patients take it—suggesting it could potentially be a once-a-day drop—the company doesn’t have the clinical evidence to back it up as of yet.
“We’re pretty confident that we’re going to get to once a day,” McVicar says, “[but] we haven’t proven it yet.”
That will be one of the things Inotek does in its new mid-stage study. It plans to see how the drug candidate works in tandem with latanoprost, and will dose groups of patients either once or twice per day. Aerie is a little ahead of Inotek—it is planning to kick off a late-stage clinical trial for AR-13324 in mid-2014. But Inotek hopes that by having sets of data for trabodenoson both as a monotherapy and a combination treatment, it’ll be ripe for either an IPO of its own, or a sale.