Vertex Pharmaceuticals (NASDAQ:VRTX) shares climbed about 6% to $488.52 in premarket trading Thursday after the company reported encouraging results from a late-stage clinical trial of its kidney disease treatment povetacicept and said it plans to pursue U.S. regulatory approval.
The drug is being developed to treat IgA nephropathy and showed a 52% reduction in proteinuria—a key indicator of kidney damage—after 36 weeks of treatment, compared with a 4.3% decline in patients receiving a placebo. The Phase 3 RAINIER study met its primary interim endpoint, delivering a placebo-adjusted proteinuria reduction of 49.8%.
Vertex said the results from the trial, which enrolled 199 patients, will support a planned submission for U.S. approval. At the 36-week mark, 42% of patients treated with povetacicept reached KDIGO target proteinuria levels below 0.5 grams per day, compared with 6% of those in the placebo group.
The company noted that upper respiratory infections were more common among patients receiving povetacicept, occurring in 18.3% of participants versus 11.4% in the placebo arm. Vertex also said the study population represented a more difficult-to-treat group, characterized by longer times since diagnosis and greater use of SGLT2 inhibitors.
Analysts offered mixed reactions to the trial outcome.
Barclays analysts said, “Though we note many expected the data to be positive, we think UPCR reduction (~50% pbo-adj) comes in at the higher end of investor expectations. We think totality of data and cross-trial comparisons suggest best-in-class efficacy.”
However, analysts at Baird were more cautious, writing, “The Ph3 RAINIER readout of povetacicept in IgAN drove some upside in after-hours trading, but we continue to think the optimism is misplaced, with a UPCR reduction nearly identical to Otsuka’s (OTSKY, not covered) approved APRIL inhibitor, Voyxact. With Otsuka in the pole position and no meaningful differentiation for povetacicept, we continue to think there is too much hype around this program being the next major growth driver for Vertex when first and best-in-class is already out there.”