Micrograph of multiple myeloma neoplasm from bone marrow biopsy
Credit: OGphoto/Getty Images

Scientists at the Indiana University Melvin and Bren Simon Comprehensive Cancer Center have initiated a first-in-human clinical trial for patients suffering from relapsed multiple myeloma using the immunotherapy REGN5459 with a 90 percent response rate when applying high doses of the drug.

Multiple myeloma is an incurable cancer of plasma cells leading to persistent bone pain, shortness of breath and fatal infections. Despite the existence of therapies which allow patients to live with the disease, relapse rates remain relatively high, revealing the need for new therapy options that are able to slow down recurrent forms of the cancer.

Presenting at the American Association for Cancer Research (AACR) 2023 Annual Meeting in Orlando, researchers have now been able to achieve high response rates to an immunotherapy drug called REGN5459 in patients who had stopped responding to treatment or relapsed after three or more lines of therapy.

In the Phase I and Phase II clinical trial, the team is treating 43 patients with REGN5459—a bispecific antibody. The drug targets the cancer cells by simultaneously binding two proteins. The first one, called BMCA is expressed on myeloma cells while the second one, called CD3 is expressed on T cells of the immune system.

“What’s unique about this molecule is that it grabs onto the T cells lightly compared to other agents. The purpose for this is to try and stimulate the T cells but slow down the inflammation that this immune reaction may cause,” explained Attaya Suvannasankha, MD, associate professor of clinical medicine at Indiana University Melvin and presenter of the study.

During Phase I of the study, patients received doses of REGN5459 ranging from 3 mg to 900 mg. For Phase II, a dose of 480 mg was selected. Patients who received higher doses of the drug showed a 90.5 percent response rate, while the overall response rate was at 65 percent.

At the time of presenting, the patients had been followed for nearly nine months with 78 percent of responding patients expected to remain in remission at the one-year mark. The scientists say that these results are phenomenal considering the average survival rate of relapsed multiple myeloma being as short as six months. The study is ongoing and the researchers hope to continue their initial success.

“We are committed to providing novel treatments to our patients with myeloma who deserve better treatment choices, to live longer and it is our aspiration to hopefully contribute to finding a cure for this disease.”

“Clinical trials like this one not only can provide direct benefit to patients, but also, we learn from every patient being treated on the clinical trial; and it helps us to be even better. We are so incredibly grateful to our patients who put their trust in us,” Suvannasankha concluded in a press statement.

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