A serious adverse event occurred in the phase 1/2 trial of Magenta Therapeutics’ leukemia medicine which resulted in the company having to put a stop to the dosage in a group of patients.
Magenta Therapeutics is a relatively new company in the clinical-stage biotechnology realm. It was founded in 2015 just over 7 years ago and is headquartered in Massachusetts, United States.
The drug, MGTA-117, is being examined in relapsed acute myeloid leukemia and myelodysplastic syndrome in the dose-escalation split-phase study. Several doses are being tested by the company, one of which is 0.13 mg/kg in cohort 4. Two of the three patients that were dosed in this specific group encountered dose-limiting toxicities.
On December 13, following an investor presentation for MGTA-117, the first adverse event reports were received, followed by another adverse event report on December 15, two days after.
According to a press release by Magenta, there were no problems related to dose-limiting toxicities with the first patient who received MGTA-117, but there was a grade 4 severe adverse event experienced by the second patient which was respiratory-related and may be linked to the study drug. According to the release, the event was later said to be an unexpected but suspected adverse reaction because of lung involvement. Grade 4 enzyme elevations were also prevalent in the patient.
Following the second adverse event report on December 15, a third report was received regarding the dosed patient experiencing a severe respiratory event on the same day. The third report activated the prespecified rule of stopping the dosage.
Since experiencing the adverse event, the first patient has seen improvement in liver enzyme levels as well as respiratory status. The second patient who faced the adverse event has also shown improvement in respiratory status. According to Magenta, the FDA has been notified with the data on the first patient while the second event has been made known as the report is in preparation.
The company will move forward with cohort 3 of the trial, which tests a 0.8 mg/kg dose, which is lower than that of cohort 4. The first 15 patients’ data from the cohort were presented at the American Society of Hematology annual meeting earlier this month, revealing no dose-limiting toxicities. The company is of the view that the risk-profit balance of this dose is stable enough to move on with enrollment.
About eight months ago in April, the company let go of nearly 14% of its staff and cut down its therapy pipeline. Back then MGTA-117 had become the lead asset from Magenta’s targeted conditioning program. MGTA-117 had previously been put on clinical hold by the FDA before getting started. The FDA wanted another test to notify safety monitoring as well as dose escalation in the planned phase 1/2 clinical study. Because of the clinical hold, the study had to face a few months of delay.