Insmed has announced that its oral drug Brinsupri did not meet its goals in a Phase IIb trial for chronic rhinosinusitis without nasal polyps. As a result, the company will discontinue development of Brinsupri for this indication.
The study, known as BiRCh, included nearly 290 patients who were assigned to receive either 10 mg or 40 mg of Brinsupri or a placebo, along with their usual mometasone furoate nasal spray. After 24 weeks, those on Brinsupri saw reductions in their Sinus Total Symptom Score (sTSS) by 2.2 and 2.33 points respectively. However, patients in the placebo group also experienced an improvement, with a decrease of 2.44 points.
Analysts at Guggenheim Partners described the results as “a rare disappointment” for Insmed and noted that “the BiRCh trial was well-conducted and delivered clear results, but the patients on placebo performed much better than expected.” They added that after discussions with Insmed management, it was clear that “results were so unequivocal that they needed minimal time to process the results and decide to discontinue all further work in this indication.”
Despite this setback, Guggenheim analysts believe the impact will be limited because of Brinsupri’s potential in non-cystic fibrosis bronchiectasis (NCFB). “We continue to see Brinsupri having ~$9Bn in peak sales potential in NCFB alone,” they wrote.
Earlier this year, Insmed reported positive data from a Phase IIb study of its trepostinil palmitil inhalation powder (TPIP) for pulmonary arterial hypertension. The treatment led to a significant improvement in pulmonary vascular resistance and six-minute walk distance. The company plans to begin a Phase III trial for TPIP early next year and is preparing another late-stage study for pulmonary hypertension associated with interstitial lung disease.
Guggenheim remains optimistic about Insmed’s business prospects overall: “We believe the Street continues to significantly underappreciate the potential for TPIP to become the preferred treprostinil across multiple large indications,” according to their statement.
