Antibody Treatment Makes Inroads Against Multiple Myeloma

MONDAY, Dec. 12, 2022 (HealthDay News) -- An experimental immunotherapy appears highly effective in attacking bone marrow cancer, with nearly three in four patients responding to the treatment, new clinical trial results show.

The drug, talquetamab, works by binding to the body's immune cells as well as to multiple myeloma cancer cells.

The therapy -- called a bispecific antibody -- directs white blood cells to attack and kill multiple myeloma cells. Researchers described the strategy as bringing your army right to the enemy.

In phase 2 clinical trials, about 73% of patients were helped by the drug, researchers reported over the weekend at an American Society of Hematology meeting. A phase 2 trial reveals more about the safety and effectiveness of a treatment.

The trial included nearly 300 patients whose multiple myeloma had returned despite treatment with at least three different cancer drugs.

More than 30% of patients who responded to the drug appeared to be cancer-free following treatment with talquetamab, researchers report. Another 60% of those who responded had a very good response, where their cancer was substantially reduced.

It took a little over a month for patients to respond to the drug, and the average duration of response to date is more than nine months, researchers said.

Multiple myeloma patients whose cancer returns after standard and targeted treatment tend to have a poor prognosis. But talquetamab targets a different receptor on the cancer cells from other myeloma drugs, offering fresh hope to those patients, researchers said.

"This means that almost three-quarters of these patients are looking at a new lease on life," said lead researcher Dr. Ajai Chari, director of clinical research in the Multiple Myeloma Program at Mount Sinai's Tisch Cancer Institute in New York City.

The response rate seen with talquetamab is higher than that for most currently accessible therapies for multiple myeloma, Chari said. He added it could offer a viable option to those whose blood cancer has become resistant to treatment.

"Talquetamab induced a substantial response among patients with heavily pretreated, relapsed or refractory multiple myeloma, the second-most-common blood cancer," Chari said in an institute news release. "It is the first bispecific agent targeting the protein GPRC5D in multiple myeloma patients."

Side effects were relatively frequent, but described by researchers as typically mild.

About three-quarters of patients experienced cytokine release syndrome, a dangerous but treatable inflammatory response that often occurs with immunotherapy. About 60% also developed skin-related side effects like rash, about half reported that their taste had changed, and about half reported nail disorders.

However, only about 5% of patients dropped out due to the side effects.

One expert unconnected to the new trial said the results could be a big win for patients.

"It is exciting that another new target immunotherapy may soon be available for patients with myeloma and hopefully the new therapies could be used earlier during the course of disease," said Dr. Henry Fung. He's chair of the Department of Bone Marrow Transplant and Cellular Therapies at Fox Chase Cancer Center in Philadelphia.

The response of patients who've already been exposed to standard anti-tumor drugs, but then go on to relapse, is often "poor," Fung explained. However, talquetamab's mechanism of action represents "an excellent target in myeloma therapy and may address the unmet need" of these patients, he said.

The clinical trial was funded by the drug company Janssen, which developed talquetamab.

Results presented at meetings are usually considered preliminary until published in a peer-reviewed medical journal.

More information

The American Cancer Society has more about multiple myeloma.

SOURCES: Henry Fung, MD, chair, Department of Bone Marrow Transplant and Cellular Therapies, Fox Chase Cancer Center, Philadelphia; Icahn School of Medicine at Mount Sinai, news release, Dec. 10, 2022