Omeros has stopped a phase 3 trial of narsoplimab in kidney disease patients after an interim analysis found it was destined to fail, adding another plot line to its epic, ongoing attempt to get the candidate to market.
Seattle-based Omeros filed for approval of the anti-MASP2 antibody as a treatment for a complication of hematopoietic stem cell transplant in 2020. The FDA rejected the request, prompting Omeros to formally challenge the decision and leading to the identification of a potential path forward in the indication. In parallel, Omeros worked toward phase 3 data on narsoplimab in immunoglobulin A (IgA) nephropathy.
The nephropathy project ended in failure Monday. An interim review found narsoplimab was statistically no better than placebo at reducing proteinuria. The condition is defined by high levels of protein in urine and is an indicator of kidney damage.
Omeros linked its drug candidate to a 64% reduction in proteinuria in a phase 2 clinical trial, a figure that looked highly competitive compared to products and prospects including Calliditas Therapeutics’ Tarpeyo and Novartis’ iptacopan. However, the phase 2 study lacked a control arm. When put up against placebo in phase 3, the effect of narsoplimab vanished.
According to Omeros, the reduction in urine protein excretion on the placebo group “was markedly greater than that reported in trials of other agents in IgA nephropathy.” Biotechs sometimes use a high placebo rate to justify further work on failed candidates, but Omeros has moved decisively away from IgA nephropathy, revealing it will stop the study and dropping plans to seek approval in the indication.
The pivot eliminates a potential challenger to Calliditas and Travere Therapeutics, the incumbents on the market, and frees up Omeros to invest in other projects. Omeros ended June with $341.3 million, a sum it said will fund operations into 2025.
Shares in Omeros fell 47% to $1.20 in premarket trading Monday from a Friday close of $2.27.