Simple Blood Test Identifies Multiple Myeloma Patients Likely to Benefit from CAR-T Immunotherapy

Multiple myeloma, a type of blood cancer originating from plasma cells in the bone marrow, sees almost all patients experiencing a relapse at some stage. This means that the cancer returns even after initially successful treatment. For such relapses, Chimeric Antigen Receptor T-cell (CAR-T) immunotherapy is employed, involving the collection and genetic modification of a patient's immune cells to target and destroy cancer cells. These engineered CAR-T cells are then reintroduced into the patient’s body to attack BCMA, a protein abundantly present in multiple myeloma cells. This method is an active FDA-approved treatment with widespread application. However, until recently, there was no reliable method to predict the efficacy of BCMA CAR-T post-treatment. Now, researchers have developed a simple blood test that counts lymphocytes (a type of white blood cell) to predict the success of CAR-T immunotherapy in patients with relapsed multiple myeloma. If the treatment is likely to fail, this insight will allow physicians to pursue alternative treatments more quickly.

In a multicenter collaborative study by several notable institutions including Weill Cornell Medicine (New York, NY, USA), researchers observed that patients experiencing an increase in their absolute lymphocyte count (ALC) within the first 15 days post-CAR-T infusion showed a greater likelihood of complete response and extended progression-free survival compared to those with lower ALCs on day 15. This study, published in the journal Blood Advances on May 22, analyzed data from 156 patients treated with BCMA-CAR-T therapy between 2017 and 2023 for relapsed multiple myeloma across three medical centers. The patients’ ALCs were measured five days prior to and throughout the first 15 days following BCMA CAR-T treatment.

The findings indicated that patients with higher ALC at day 15 had a significantly better response to treatment with their cancer under control for an average of 30 months, whereas those with lower counts typically experienced only six months of progression-free survival. Laboratory analyses suggested that a higher ALC might indicate more effective proliferation and activity of BCMA CAR-T cells in the body, potentially explaining why the cancer was kept in check. The researchers are now investigating strategies to boost BCMA CAR-T cell performance in patients presenting lower ALCs to enhance treatment outcomes.

“If doctors can identify patients who are more likely to have a poor response to BCMA CAR-T, other treatments can be explored or given earlier,” said lead author Dr. Mateo Mejia Saldarriaga, assistant professor of medicine in the Division of Hematology and Medical Oncology at Weill Cornell Medicine and an oncologist at NewYork-Presbyterian/Weill Cornell Medical Center. “The treatment has been a great tool, but there is still room for improvement.”

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