Pfizer’s investigational cancer immunotherapy, elranatamab, has received a Breakthrough Therapy Designation from the US Food and Drug Administration (FDA) for the treatment of relapsed or refractory multiple myeloma (RRMM), the company announced.
The designation is based on six-month follow-up data from one cohort of MagnetisMM-3, an open-label, multi-centre, single arm, phase 2 study evaluating the safety and efficacy of elranatamab monotherapy in patients with RRMM.
Patients received a subcutaneous 76mg weekly dose of elranatama, with a two-step-up priming dose regimen administered during the first week. In the study, elranatamab demonstrated a manageable safety profile, and at a median follow-up of 6.8 months, patients achieved an overall response rate of 61%.
In terms of safety, the company reported that the most common treatment-emergent adverse event regardless of causality was cytokine release syndrome, with the majority of reported events being either grade one or two.
Multiple myeloma is an incurable blood cancer affecting plasma cells found in bone marrow. If plasma cells become damaged, they can transform and grow in an abnormal way. The production of abnormal cells can result in an overcrowding in the bone marrow, suppressing the growth of healthy cells.
As the disease progresses, relapses for patients become more aggressive with each new line of therapy and remissions become progressively shorter.
Elranatamab is a B-cell maturation antigen (BCMA)-CD3-targeted bispecific antibody (BsAb), a novel form of cancer immunotherapy that binds to and engages two different targets at once.
Elranatamab is designed to bind to BCMA, which is highly expressed on the surface of multiple myeloma (MM) cells, and the CD3 receptor found on the surface of T-cells, bridging them together and activating the T-cells to kill the myeloma cells.
Commenting on the FDA’s decision, Chris Boshoff, chief development officer, oncology and rare disease, Pfizer global product development, said: “The FDA’s Breakthrough Designation recognises the potential of elranatamab as an innovative medicine for people with multiple myeloma whose disease has relapsed or is refractory to existing treatments, which at present leaves very few avenues for staving off this currently incurable cancer.”
In addition to the Breakthrough Therapy Designation, elranatamab has been granted Orphan Drug Designation by the FDA and the European Medicines Agency for the treatment of MM. The UK Medicines and Healthcare Products Regulatory Agency has also granted elranatamab Innovative Medicine Designation and the Innovation Passport, also for the treatment of MM.