Merck's latest allergy pill hits the mark in Phase IIb

Merck ($MRK) and its biotech partner are working to build a franchise of allergy immunotherapies, and their latest effort, an oral treatment for house dust mite reactions, improved symptoms in a mid-stage study.

In a Phase IIb trial on 124 patients with dust mite allergies, Merck's under-the-tongue MK-8237 improved 24-week nasal symptoms by 49% at its highest dosage, the company said, and the drug notched promising dose- and time-dependent reductions compared to placebo at 8 and 16 weeks, as well. Merck is measuring efficacy by charting itchy nose, blocked nose, runny nose, sneezing, ocular irritation and watery eyes, and the study's most common adverse events were throat irritation and oral swelling.

Now, confident in MK-8237's safety and efficacy, Merck is screening patients for a Phase III trial, looking to bolster its mid-stage findings and get the drug in front of regulators.

Like Merck's other two collaborations with ALK-Abello, the drug is designed to expose patients to gradually increasing levels of house dust mite allergen, slowly training the immune system to fight allergic reactions and reducing the occurrence of symptoms. The partners are awaiting expected FDA approvals for the grass allergy immunotherapy Grastek and ragweed pollen-blocking Ragwitek, two drugs already recommended by agency advisers.

But Merck's nascent oral allergy franchise is likely to face an uphill battle on the commercial front. Injection regimens currently dominate the market for severe allergy treatment, and while a daily oral treatment is certainly more convenient than frequent trips to a physician, shots are cheap, and their safety and efficacy is well-established.

Accordingly, peak sales estimates for Ragwitek hover around just $300 million, while Grastek has a consensus of roughly $150 million. But some analysts, including Morningstar's Damien Conover, believe Merck's marketing heft gives it a shot at convincing a critical mass of physicians to ditch needles in favor of sublingual tablets, giving the drugmaker an allergy franchise that could top out north of $1 billion if all goes according to plan.

For ALK, the Phase IIb success puts it in line for more potential milestones. Under the terms of the Merck deal, the biotech is up for as much as $290 million plus royalties on any approved drugs.

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