About 81% of people with newly diagnosed multiple myeloma who received the antibody drug daratumumab along with standard therapy were alive without their cancer worsening six years later, compared with 56% of those who got standard therapy alone. The long-term results from the PERSEUS trial were presented at the International Myeloma Society's annual meeting in Glasgow, Scotland, held Sept. 23 to 26, OncLive reported.
Multiple myeloma is a cancer of plasma cells in the bone marrow. It is not considered curable, and most patients eventually relapse, so the length of a first remission shapes years of a person's life. For patients and families weighing a first treatment plan, six-year data offer a longer view than most trials provide.
The update also showed longer survival in the daratumumab group. The results have not yet appeared in a peer-reviewed journal, and they apply to a specific group: patients 70 or younger who were healthy enough for a stem cell transplant.
Six-Year Figures From 709 Patients
PERSEUS enrolled 709 adults ages 18 to 70 in Europe and Australia. About half received daratumumab plus bortezomib, lenalidomide and dexamethasone, a four-drug combination often called D-VRd, before and after a stem cell transplant, followed by maintenance with daratumumab and lenalidomide. The others received the same plan without daratumumab.
After a median follow-up of about 81 months, 81.1% of the daratumumab group had not progressed at 72 months, compared with 56.1% of the standard group. That corresponds to a 65% lower risk of progression or death. Overall survival at six years was 85.9% versus 78.6%, with 51 deaths in the daratumumab group and 84 in the standard group.
Deep responses were also more common. About 70% of daratumumab patients reached minimal residual disease negativity lasting at least a year, meaning sensitive tests found virtually no remaining myeloma cells, compared with 36% of standard patients. "After approximately 7 years of median follow-up, the PERSEUS regimen confirmed deep and durable benefit of daratumumab-based treatment across induction/consolidation and maintenance settings," said lead investigator Dr. Pieter Sonneveld of the Erasmus MC Cancer Institute in Rotterdam.
Reading Progression-Free Survival Figures
Progression-free survival measures how long patients live without their cancer growing or spreading. It is not the same as a cure, and it does not directly measure how long people live. For myeloma, it matters because each relapse usually means a new round of treatment with more side effects.
The trial also let many patients stop daratumumab. Patients whose tests showed no detectable disease for 12 months could stop the drug, and about 73% of those on maintenance did so after a median of about 27 months. Most of them had not needed to restart it at the time of the analysis, which could ease the burden of years of injections.
Fewer patients in the daratumumab group needed a second line of treatment, 14.2% compared with 39.2% in the standard group. Treatment was also stopped because of side effects less often, 13.4% versus 31.4%.
People with high-risk genetic features in their myeloma saw a smaller benefit. Their six-year progression-free rate was 55% with daratumumab versus 33% without it, showing that outcomes still vary widely by disease type.
Limits and Industry Ties to Weigh
These are conference results, and full safety details from the six-year analysis were not included in the public report. In the original trial report published in the New England Journal of Medicine, serious side effects occurred in 57% of the daratumumab group and 49% of the standard group. Severe drops in infection-fighting white blood cells were also more common with daratumumab, according to a National Cancer Institute summary of the original results.
In the standard group, 72.8% of patients who went on to a second treatment later received an anti-CD38 antibody such as daratumumab. That means the survival comparison reflects starting the drug early versus later, not getting it versus never getting it.
The trial was led by the European Myeloma Network with support from Johnson & Johnson, which makes the under-the-skin form of the drug, Darzalex Faspro. The FDA approved the four-drug combination for transplant-eligible patients in July 2024 for induction and consolidation. The U.S. label does not include daratumumab maintenance, the part of PERSEUS that ran longest.
Questions Patients and Caregivers Can Raise
Patients newly diagnosed with myeloma can ask their oncologist whether they are considered transplant-eligible and whether a daratumumab-based four-drug regimen is part of their plan. It is also fair to ask whether their myeloma has high-risk genetic features, since that affects expected outcomes. Those already in treatment should not change their regimen without talking with their care team.
Caregivers may want to ask about infection prevention, including which vaccines are recommended during treatment and which symptoms need an urgent call. Fever, chills or a new cough during myeloma treatment can signal a serious infection and should be reported to the care team right away.
Cost questions matter too. Families can ask whether insurance covers daratumumab maintenance, since that use is outside the current U.S. label, and whether the treatment center has a financial counselor who can help with patient assistance programs.
"This is a field being redrawn in real time," International Myeloma Society President Dr. Philippe Moreau said in the society's annual meeting announcement. For patients, the takeaway is steadier: adding daratumumab kept more people in remission for longer, and a full published report will add needed safety detail.
Key Questions Answered
What did the PERSEUS update show?
At six years, 81.1% of patients who received daratumumab with standard therapy had no cancer progression, compared with 56.1% of those who received standard therapy alone.
Did patients live longer?
Yes. Six-year overall survival was 85.9% with daratumumab and 78.6% without it.
Who does this apply to?
Adults 70 or younger with newly diagnosed multiple myeloma who were eligible for a stem cell transplant.
What is progression-free survival?
It measures how long patients live without their cancer growing or spreading. It is not the same as a cure.
Is this regimen approved in the U.S.?
The FDA approved Darzalex Faspro with VRd in July 2024 for induction and consolidation in transplant-eligible patients. Daratumumab maintenance is not part of the U.S. label.
Have the six-year results been peer-reviewed?
Not yet. They were presented at a medical meeting and have not been published in a journal.
Published by Medicaldaily.com
