FDA Grants Fast Track Designation to NX-5948 for R/R WM

A novel treatment for Waldeström macroglobulinemia has been granted a fast track designation by the FDA.

The Food and Drug Administration (FDA) has granted fast track designation to NX-5948 for the treatment of adults with relapsed or refractory Waldenström macroglobulinemia who have already received at least two prior lines of therapy, including a Bruton’s tyrosine kinase (BTK) inhibitor.

NX-5948 is an oral BTK degrader currently being evaluated in a phase 1a/1b clinical trial of patients with relapsed or refractory B cell malignancies, according to a news release from manufacturer Nurix Therapeutics, Inc.

Fast track designation, according to the FDA’s website, is intended to facilitate the development and expedite the review of drugs that treat serious conditions and would fill an unmet medical need.

“Fast track designation for NX-5948 is an important recognition of the unmet patient need in Waldenström macroglobulinemia, particularly in the growing number of patients whose cancer has progressed following BTK inhibitor therapy,” said Dr. Arthur T. Sands, the president and chief executive officer of Nurix. “This designation follows encouraging safety and efficacy data from our ongoing phase 1 clinical trial, demonstrating early promise of clinical benefit with potential for durable outcomes. We continue to enroll Waldenström’s macroglobulinemia patients in the ongoing phase 1b expansion cohort and anticipate sharing additional clinical data in 2025.”

Nurix announced study findings in October 2024 that demonstrated an objective response rate of 77.8% (seven of nine patients evaluable for response) for NX-5948 among patients with Waldenström macroglobulinemia,

NX-5948, according to the National Cancer Institute, is intended to result in the inhibition of the growth of malignant B cell that overexpress BTK.

The multicenter phase 1a/1b trial, according to its listing on clinicaltrials.gov, is currently recruiting patients and plans to enroll approximately 292 patients, and is expected to be completed in January 2027. In addition to Waldenström macroglobulinemia, patients in the trial can have chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL), diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL),

marginal zone lymphoma (MZL), follicular lymphoma (FL) or primary central nervous system lymphoma (PCNSL).

Waldenström macroglobulinemia, as Nurix explained in the news release, is a slow-growing form of non-Hodgkin lymphoma that involves the replacement of normal healthy bone marrow cells with malignant lymphocytic cells, and can result in anemia, bleeding and impaired immune function.

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The disease has an incidence rate of approximately three cases per million people in the United States, with between 1,000 and 1,500 people being diagnosed with Waldenström macroglobulinemia in the United States every year, according to the American Cancer Society.

Waldenström macroglobulinemia, the American Cancer Society stated on its website, is more common in men than in women and more common in White people than in Black people, and the average age of diagnosis is 70. According to Nurix, there are currently no therapies approved to treat patients with Waldenström macroglobulinemia after they have been treated with BTK inhibitors.

NX-5948 previously received fast track designation in January 2024 for the treatment of adults with relapsed or refractory CLL or SLL who had received at least two prior lines of therapy, including a BTK inhibitor and a B-cell lymphoma 2 (BCL2) inhibitor.

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