Merck, ALK’s dust mite immunotherapy gains FDA review

Merck ($MRK) and its Danish biotech research partner ALK-Abelló have hit a positive regulatory milestone for their investigational allergy immunotherapy after the FDA accepted the drug’s biologics license application for review.

MK-8237 is a house dust mite SLIT-tablet and the two companies are seeking a license for the drug to help treat allergic rhinitis with or without conjunctivitis caused by house dust mite-specific allergens.

Like Merck's other 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 have already gained FDA approval for the grass allergy immunotherapy Grastek and ragweed allergy treatment Ragwitek back in 2014. Peak sales estimates for Ragwitek hover around $300 million, while Grastek has a consensus of roughly $150 million--but Merck’s allergy franchise could top out north of $1 billion should it gain approval for MK-8237, given its marketing might.

ALK is also in line for $290 million plus royalties on any approved drugs coming from the collab.

The BLA for the drug is supported by several late-stage trials, including the pivotal Phase III Mitra trial, with top-line results showing the treatment significantly reduced patients’ risks of moderate to severe asthma exacerbations.

In a Phase IIb study, Merck hit its primary endpoint in a test of 124 patients with house dust mite-induced allergic rhinitis, with or without conjunctivitis, using an environmental exposure chamber.

In the study, Merck's under-the-tongue MK-8237 improved 24-week nasal symptoms by 49% at its highest dosage, and the drug notched promising dose- and time-dependent reductions compared to placebo at 8 and 16 weeks. 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.

“We are proud of Merck’s longstanding respiratory heritage and commitment to helping patients with allergies,” said Stuart Green, VP of clinical research at Merck Research Laboratories.

“This is an important milestone in the clinical development of MK-8237 as a potential new option for adults with house dust mite-induced allergic rhinitis with or without conjunctivitis. House dust mites are a source of a common perennial allergen and frequently live in household objects such as upholstered furniture, bedding and carpeting.”

House dust mites (HDM) are the most common cause of allergy in the world, according to Merck, and a condition it says is the subject of an unmet medical need.

HDM allergy appears early in life and is present all year round, and ALK estimates that one out of 10 adults in Europe suffering from allergic rhinitis has a condition which is not well controlled.

The drug is also believed to help with certain asthmatics as the majority of patients who have HDM allergic asthma also have allergic rhinitis. In addition, around 50% of asthmatic patients are reported to be sensitized to HDM, according to ALK.

The drug has already been approved in 11 European countries, but not yet centrally via the EMA. 

-see the release