Data from the Phase III KOMET trial indicates that Koselugo (selumetinib), an oral MEK inhibitor, has shown a statistically significant and clinically meaningful improvement in objective response rate (ORR) compared to placebo in adult patients suffering from symptomatic, inoperable plexiform neurofibromas (PN) associated with neurofibromatosis type 1 (NF1). The findings offer a potential new treatment avenue for adults with NF1, a population with limited targeted therapy options.
The global, randomized, double-blind, placebo-controlled, multi-center KOMET trial enrolled 145 patients from 13 countries across the United States, Asia, Australia, South America, and Europe. Participants were randomized in a 1:1 ratio to receive either Koselugo or a placebo for twelve 28-day cycles. The primary endpoint was the confirmed ORR by cycle 16, assessed by independent central review based on response evaluation criteria in neurofibromatosis and schwannomatosis.
Clinically Meaningful Improvement
The ORR was defined as the percentage of patients exhibiting at least a 20% reduction in tumor volume by cycle 16. After the initial 12 cycles, patients in the placebo group were switched to Koselugo, while those already on Koselugo continued for an additional 12 cycles. Patients completing both treatment periods had the option to participate in a long-term extension.
According to Ignacio Blanco Guillermo, MD, PhD, principal investigator of the KOMET trial, the data indicates that Koselugo has the potential to positively impact patient care by reducing the size of plexiform neurofibromas. He noted that many patients experience functional impairment and symptoms that substantially impact their lives due to limited treatment options.
Safety Profile
The safety profile of Koselugo in the KOMET trial was consistent with previous clinical trials involving children and adolescents, with no new safety signals identified. Adverse events associated with Koselugo include cardiomyopathy, ocular toxicity, gastrointestinal toxicity, skin toxicity, increased creatinine phosphokinase, increased levels of vitamin E, risk of bleeding, and embryo-fetal toxicity.
Implications for NF1 Treatment
Marc Dunoyer, CEO of Alexion, highlighted that the KOMET trial reinforces the company's leadership in advancing potential treatment options for people living with NF1. Scot Ebbinghaus, VP, global clinical development, Merck Research Laboratories, added that the positive results from the Phase III KOMET trial demonstrate the potential to expand the use of Koselugo beyond pediatric patients to also treat adult patients living with this rare and challenging genetic condition.
Plexiform neurofibromas occur in 30% to 50% of patients with NF1. The results of the KOMET trial will be shared with regulatory authorities.
