FDA Grants Priority Review to Elranatamab for R/R Multiple Myeloma

A biologic licenses application for elranatamab as a treatment for relapsed or refractory multiple myeloma has been accepted and granted priority review by the FDA, according to a press release from Pfizer.¹

“We believe that elranatamab, if approved, has the potential to become the next standard of care for multiple myeloma given its favorable clinical results and convenient subcutaneous route of administration,” according to the manufacturers of elranatamab.

The European Medicines Agency (EMA) has also accepted a marketing authorization application for elranatamab in the same indication.

The applications are supported by data from the phase 2 MagnetisMM-3 trial (NCT04649359), assessing single-agent elranatamab in those with multiple myeloma whose disease was refractory to at least 1 proteasome inhibitor, immunomodulatory agent, and anti-CD38 monocloncal antibody. According to a data read out at the 2022 American Society of Hematology Annual Meeting and Exposition, the agent yielded an objective response rate (ORR) of 61%, with 55% of patients having a very good partial response or better and 84% being likely to maintain a response after 9 months.

In the MagnetisMM-3 study, a 2-step-up priming dose of 12 mg and 32 mg mitigated the rate and severity of cytokine release syndrome (CRS) and immune effector cell–associated neurotoxicity syndrome (ICANS) in 119 patients in the B-cell maturation agent–naïve cohort A (n = 123).

All instances of CRS were grade 1 or 2 and occurred in 43% of patients following their first dose and 24% following their second dose. ICANS occurred in 3% of patients and was not severe; investigators observed no fatal neurotoxicity events.

“We believe that elranatamab, if approved, has the potential to become the next standard of care for multiple myeloma given its favorable clinical results and convenient subcutaneous route of administration,” Chris Boshoff, MD, PhD, chief development officer of Oncology and Rare Disease at Pfizer Global Product Development, said in the press release.

Patients who enrolled on the study received elranatamab subcutaneously at 76 mg per week on a 28-day cycle with a step-up priming dosing regimen, wherein investigators administered 12 mg and 32 mg on day 1 and day 4, respectively, during cycle 1. Patients receiving 6 or more cycles who had a partial response or better for at least 2 months received elranatamab once every 2 weeks.

The primary end point of the trial was ORR. Secondary end points included duration of response, progression-free survival, time to response, overall survival, minimal residual disease negativity rate, treatment-emergent adverse effects, and laboratory abnormalities.

Patients 18 years and older with a diagnosis of multiple myeloma based on International Myeloma Working Group criteria and measurable disease were eligible for enrollment on the trial. Additional inclusion criteria included being refractory to at least 1 immunomodulatory drug, 1 proteasome inhibitor, and 1 anti-CD38 antibody. Moreover, patients needed an ECOG performance status of 2 or less and have resolved acute effects of any prior therapy to baseline severity.

Investigators are also evaluating elranatamab in several other multiple myeloma indications, including the double class-exposed setting in the phase 3 MagnetisMM-5 trial (NCT05020236), in those with transplant ineligible newly diagnosed disease in the phase 3 MagnetisMM-6 trial (NCT05623020), and as maintenance therapy in newly diagnosed patients following transplant in the phase 3 MagnetisMM-7 trial (NCT05317416).

All previously described trials are currently enrolling.

The FDA previously granted breakthrough therapy designation to elranatamab for relapsed or refractory multiple myeloma in November 2022.² The designation was supported based on 6-month follow-up data from the MagnestisMM-3 trial.

References

1. Pfizer’s elranatamab receives FDA and EMA filing acceptance. News release. Pfizer. February 22, 2023. Accessed February 22, 2023. http://bit.ly/3KtAwsI
2. Pfizer’s elranatamab granted FDA breakthrough therapy designation for relapsed or refractory multiple myeloma. News release. Pfizer. November 3, 2022. Accessed February 22, 2023. http://bit.ly/3h9I9YM