Dive Brief:
- A small, Californian biotechnology company reported on Tuesday that an experimental medicine it's been developing for a form of bone marrow cancer succeeded in a late-stage clinical trial.
- Significantly more participants who received the drug rather than an older treatment hit the trial's main goal of a 50% or greater reduction in symptoms related to their disease. Called myelofibrosis, the rare blood cancer can cause severe anemia and, in turn, fatigue, weakness and shortness of breath.
- The drug, known as momelotinib, also appeared to improve other health measures important to myelofibrosis patients, such as reducing the size of their spleens and their need for blood transfusions. Sierra Oncology, the company behind momelotinib, said it plans by June to submit an application for approval to the Food and Drug Administration.
Dive Insight:
Founded almost two decades ago, Sierra, which was formerly known as ProNAi Therapeutics, has staked its business on the development of momelotinib. The company acquired the drug for cheap from Gilead in 2018, after the larger biotech reported mixed results in one trial and negative data in another.
Sierra executives, some of whom worked at momelotinib's original developer before it was absorbed by Gilead, had a different view. After reviewing data from Gilead's two trials, they concluded the drug might have a positive impact on three critical measures for myelofibrosis patients: anemia, constitutional symptoms and spleen size. (An enlarged spleen is a hallmark of the disease.)
Late-stage data released Tuesday provide the most supportive evidence yet for their bet. They show that 25% of the patients given Sierra's drug, versus 9% in the active control group, reported at least a 50% reduction on a scorecard used to evaluate the severity of myelofibrosis symptoms.
That result was enough for Sierra to claim success. Additionally, the group treated with momelotinib had significantly higher rates of blood-transfusion independence, at 31% compared with 20% in the control arm, and of spleen size reductions of 35% or more. That latter endpoint was achieved by 23% of patients on the momelotinib arm and 3% of those in the control group.
The study enrolled close to 200 myelofibrosis patients who were anemic, had other symptoms of the disease and were previously treated with a kind of drug called a Janus kinase inhibitor, or JAK for short. The two myelofibrosis treatments currently approved by the Food and Drug Administration, Bristol Myers Squibb's Inrebic and Incyte's Jakafi, are both JAK-blocking drugs, as is momelotinib, though Sierra's medicine also blocks another protein named ACVR1.
The response rates seen in the momelotinib arm and the drug's apparent effects on this hard-to-treat patient population is a "very helpful outcome," according to Ruben Mesa, a co-principal investigator of the study and the executive director of the Mays Cancer Center in San Antonio, Texas. Mesa has worked and consulted with a number of drugmakers, including Sierra and Incyte.
Myelofibrosis patients face difficult symptoms as well as the prospect of frequent blood transfusions to prevent anemia, Mesa said in an interview with BioPharma Dive. "What these results show us is that, again, momelotinib as monotherapy really has significant impact against all of those challenges, and with that really would be unique" compared with other available options, he said.
Mesa added that, while effective, both Inrebic and Jakafi have some limitations, such as potentially worsening a patient's anemia. He expects that, were the FDA to approve momelotinib, the drug would influence how doctors treat myelofibrosis.
For instance, Mesa said he would reevaluate whether myelofibrosis patients who are anemic and receiving transfusions might be better off on momelotinib, even if they hadn't been treated previously. While Sierra's study evaluated momelotinib in the second-line setting, or after other JAK-blocking drugs, the company has said it hopes for a broad label that would allow use in previously untreated patients.
Sierra disclosed results from its trial via a press release. A full dataset will be presented at an upcoming meeting, said the company, which is hosting a conference call Tuesday to discuss its findings.