Omeros Corporation (NASDAQ:OMER) recently disclosed its comprehensive final findings of its clinical trial evaluating narsoplimab’s performance in hematopoietic stem cell transplant-associated thrombotic microangiopathy (HSCT-TMA).
Narsoplimab is a mannan-binding lectin-associated serine protease-2 (MASP-2) inhibitor that Omeros has been developing as a HSCT-TMA treatment. The company hopes that it will provide therapeutic relief especially for high-risk patients who have experienced poor outcomes with other treatments. Narsoplimab already received Breakthrough Therapy designation status from the Food and Drug Administration (FDA). Omeros also filed for a Biologics License Application (BLA) for the pipeline drug as a HSCT-TMA treatment.
Omeros previously presented its preliminary data for narsoplimab from a pivotal clinical trial of HSCT-TMA. However, the recently announced final data is consistent with the preliminary data and it also includes the additional data provided in the BLA. The trial involved 28-patient enrolled in an open-label, single-arm pivotal trial in which narsoplimab was administered intravenously in a single weekly dose for 8 weeks.
The final results
The biopharma revealed that it observed about 61% complete response rate from the complete analysis set. There was an average of 74% complete response rate in the per-protocol population in which patients received a protocol-specified amount of narsoplimab for a minimum of four weeks. The full analysis set demonstrated 68% 100-day survival and 83%in the per-protocol population while complete responders were at 94%.
The FAS achieved a 274-day median overall survival rate while the median survival for the per-protocol population was 361 days. The researchers could not estimate the median overall survival for the complete responders but more than half of them were alive by the end of the last follow-up.
Researchers observed similar responses in all patient subgroups that were defined by transplant complications, transplant characteristics, and baseline characteristics. Most of the individual lab markers demonstrated statistically notable improvements. The adverse effects were similar to those observed in the post-HSCT population which include nausea, fever, vomiting, neutropenia, and diarrhea. There were six deaths during the study and all of them were from causes usually observed in HSCT. Researchers did not identify any safety concerns during the study.