Pfizer pauses enrolment for trial evaluating anti-BCMA bispecific antibody

Pfizer has paused enrolment for a phase 2 trial evaluating its anti-BCMA bispecific antibody elranatamab, following three cases of peripheral neuropathy in an ongoing phase 1 study.

The company announced the pause for the MagnetisMM-3 trial, which is evaluating the investigational BCMA CD3-targeted drug in patients with relapsed/refractory multiple myeloma, in its first quarter earnings release yesterday.

Researchers identified three cases of peripheral neuropathy in the ongoing phase 1 trial, although details on the events were scarce.

Peripheral neuropathy occurs as a result of damage to the nerves outside of the brain and spinal cord, with symptoms ranging from pain and numbness to tingling and weakness in the hands, arms and feet.

Pfizer initiated the phase 2 study of elranatamab in February, with the aim of evaluating the safety and efficacy of the drug, administered subcutaneously, in patients with multiple myeloma that is refractory to at least one agent in each of the three major classes of medications approved for the disease.

“The initiation of MagnetisMM-3, our pivotal trial, is an important step in our robust and accelerated development programme for elranatamab,” said Chris Boshoff, chief development officer, oncology, Pfizer global product development.

“Bispecific antibodies hold promise as the next potential breakthrough in the treatment of multiple myeloma. We are highly encouraged by early data with subcutaneous elranatamab, which was discovered and developed at Pfizer and designed to enhance safety and convenience,” he added.

Although Pfizer has paused enrolment into the trial, the company maintained that patients who are ‘deriving clinical benefit’ from elranatamab may continue treatment.

Pfizer also announced that it is experiencing delays for another programme evaluating its investigational gene therapy candidate fordadistrogene movaparvovec for the treatment of Duchenne muscular dystrophy.

The pharma giant is aiming to progress a phase 3 trial – CIFFREO – for the therapy, although it must resolve ‘outstanding questions’ with the US Food and Drug Administration (FDA) before it can begin enrolling patients in US study sites.

The issues revolve around questions related to Pfizer’s investigational new drug application for the gene therapy, including technical aspects about its potency assay matrix.

While Pfizer is planning to continue progressing the trial globally and enrol patients at other sites, it does not expect resolution in the US in the first half of 2021, adding it is working with the FDA ‘with sense of urgency’.