新規レジメンは多発性骨髄腫の進行を緩徐にする (Abstract LBA4)

Initial findings from a pivotal phase III trial showed that daratumumab added to a standard two-drug regimen (bortezomib and dexamethasone) markedly improved outcomes for patients with recurrent or refractory multiple myeloma.

The daratumumab combination reduced the risk of cancer progression by 70%, and doubled both very good partial response rates from 29% to 59% and complete response rates from 9% to 19%. Daratumumab, the first monoclonal antibody approved for multiple myeloma, targets a protein on the surface of cancer cells called CD-38.

These data were presented in ASCO's Plenary Session, which features four abstracts deemed to have the greatest potential to impact patient care, out of the more than 5,000 abstracts featured as part of the 2016 American Society of Clinical Oncology (ASCO) Annual Meeting.

"We've suspected for a long time that CD-38 is the major treatment target for multiple myeloma, but these results are unprecedented in this cancer," said lead study author Antonio Palumbo, MD, a chief of the Myeloma Unit at the Department of Oncology, University of Torino in Torino, Italy. "It's clear now that we'll be moving to a three-drug regimen with daratumumab as the standard of care."

This first randomized clinical trial of daratumumab included nearly 500 patients with relapsed or refractory multiple myeloma. Patients received eight cycles of either regimen, followed by daratumumab maintenance therapy for patients in the daratumumab group.

"Daratumumab is a fast-acting drug ─ in many cases tumors shrank in just a month. As a result of shrinkage and slower tumor growth, patients had less pain and a better quality of life," said Dr. Palumbo.

He noted that daratumumab did not substantially worsen the most common side effects of the standard regimen. Patients in the daratumumab group experienced slightly higher rates of hematologic toxicity, infections, and peripheral neuropathy.

Longer patient follow up is needed to determine the impact of this daratumumab combination on patient survival. A clinical trial that combines daratumumab with another standard therapy for recurrent multiple myeloma is underway. Additional clinical trials are testing various daratumumab-based regimens for patients with newly diagnosed multiple myeloma.

Daratumumab is one of the first drugs with the ability to directly kill myeloma cells and at the same time stimulate the immune system response to attack the tumor. The direct effect explains rapid tumor shrinkage, whereas the immune effect sustains prolonged responses to the treatment.

"Here, we've seen what can happen for patients when we select the treatment based on a common target in multiple myeloma," said ASCO President Julie M. Vose, MD, MBA, FASCO. "The new treatment regimen appears to rapidly slow cancer growth in many patients. This study affirms the efficacy of daratumamab that was seen in earlier, smaller clinical trials in this setting."

Multiple myeloma is an uncommon cancer. In 2012, 114,250 were diagnosed worldwide. This study received funding from Janssen Research & Development.