Merck's chronic cough med gets a nay from FDA, potentially clearing first-to-market path for Bellus

The FDA rejected Merck's chronic cough treatment, potentially setting up more breathing room for competitor Bellus Health in a first-to-market battle. 

While the FDA rejected Merck's drug, Japan's health regulators accepted the oral treatment last week for people with refractory or unexplained chronic cough, in which the hacking lasts eight weeks or more. The drug will be marketed as Lyfnua in Japan. 

The FDA said no to gefapixant and requested more information related to the med's efficacy. Safety was not a cause of the regulator's hesitation, the New Jersey pharma said Monday. The drug caused tolerability concerns in two phase 3 trials, in which 15% to 20% of patients on the high dose dropped out due to adverse events. The lowest dose, 15 mg, failed in both trials. At the highest dose of 45 mg, patients experienced taste-related issues.

Merck had been positioned to win the race in bringing a P2X3 receptor antagonist for cough to market after the FDA accepted its application last March. The decision was originally expected by Dec. 21, 2021, but the FDA delayed the date to March 21, 2022, Merck revealed last July. 

RELATED: FDA accepts gefapixant for review in cough, positioning Merck to get head start on Bayer and Bellus

The pharma was ahead of Bayer, Bellus Health and Shionogi in the race to the U.S. market, but the FDA's vote of no confidence has helped close the gap for Bellus' BLU-5937, RBC Capital Markets analysts wrote in a note. 

At least one of three doses of BLU-5937 met the threshold for clinical efficacy in a phase 2b trial, the Canadian biotech said in September. Now, RBC analysts place the investigational treatment in a "potentially improved position." 

However, the FDA's complete response letter to Merck could have ripple effects on the four companies in the P2X3 space given all of the drugs in development share endpoints and measuring devices. 

RELATED: Bellus offers a scrap of analysis for chronic cough candidate in first-to-market battle with Merck

The agency's concerns could be addressed by Bellus when it meets with the FDA to form a pivotal trial design for BLU-5937 next quarter, RBC analysts wrote. Bayer's med, eliapixant, also passed muster in a phase 2b trial in September by significantly decreasing cough frequency in 24-hour cough counts versus placebo after 12 weeks. 

Given no company has received an FDA nod in refractory chronic cough, Merck will "remain committed to advancing gefapixant," said Chief Medical Officer Roy Baynes, M.D., Ph.D., also head of global clinical development, in a statement.