Guggenheim Partners now pegs peak sales for Insmed’s inhaled PAH drug at more than $6 billion, and the 12-month open-label extension data the biotech dropped this week is the reason. Patients who stayed on treprostinil palmitil inhalation powder, TPIP, held a 55.7-meter gain in six-minute walk distance through month 12, while those who crossed over from placebo gained 54.1 meters; the NT-proBNP biomarker, a marker of heart strain, fell about 60% in both the continuing-treatment group and the group that crossed over from placebo. That’s real durability data, not a topline snapshot.
I read the release: 91 patients, 45 sites, doses up to 1,280 micrograms allowed. Only the small sample size stands between “best-in-class inhaled prostanoid” and a broader label - Guggenheim’s own hedge is that “we are still multiple years away from any Phase 3 readout.” Insmed just opened that Phase 3, PALM-PAH (NCT07481981), a 24-week placebo-controlled trial, with no readout date attached yet.
Truist’s read is less rosy. Only about 21% of patients pushed past 640 µg, and just seven hit the ceiling dose. If physicians aren’t titrating up in patients who tolerate it fine, the “titrate beyond current limits” pitch that’s supposed to differentiate TPIP from existing inhaled prostacyclins doesn’t have data behind it yet. That’s the gap between the $6 billion number and the trial that has to prove it.
Insmed can afford the wait. Brinsupri, its DPP1 inhibitor approved last August for non-cystic fibrosis bronchiectasis, pulled in $207.9 million in the first quarter. TPIP’s Phase 3 readout is still years out.
Rebecca Lauren