Real-World Data Show Carfilzomib Regimens Deliver Strong Results in Multiple Myeloma

Multiple myeloma remains one of the most challenging blood cancers to treat, and for patients whose disease has returned after initial therapy or has stopped responding altogether, every treatment decision carries enormous weight. Now, one of the largest real-world studies of its kind in Germany has delivered a reassuring message: a powerful targeted drug called carfilzomib, when combined with other agents, is not only effective in everyday clinical practice but is also tolerated well enough that patients stay on treatment at remarkably high rates. The final results of the CARO study, published in the journal Annals of Hematology, offer clinicians and patients alike a clearer picture of what happens when a therapy proven in controlled trials meets the messier reality of routine care.

CARO was a prospective, multicenter, non-interventional study, registered under the identifier NCT02970747, designed specifically to observe rather than interfere. Instead of assigning patients to strict protocols, researchers followed 359 people with relapsed or refractory multiple myeloma across 69 sites throughout Germany, capturing how carfilzomib-based regimens actually performed in the hands of community oncologists and hospital hematologists. This kind of real-world evidence has become increasingly prized in oncology, because randomized clinical trials, for all their rigor, tend to enroll younger, fitter patients and enforce treatment schedules that bear little resemblance to the compromises forced by age, comorbidities, and everyday life.

The study evaluated three distinct carfilzomib-based combinations that reflect the evolving landscape of myeloma therapy. The first, known as KRd, paired carfilzomib with lenalidomide, an immunomodulatory drug, and dexamethasone, a corticosteroid. The second, Kd, combined carfilzomib with dexamethasone alone. The third and most modern regimen, KdD, added daratumumab, a monoclonal antibody that targets a protein called CD38 on the surface of myeloma cells, to carfilzomib and dexamethasone. By following all three cohorts simultaneously, CARO provided a snapshot of how German physicians deploy these options across a broad and diverse patient population.

Perhaps the most striking finding concerns adherence. Across all three treatment groups, patients remained on carfilzomib therapy at rates exceeding 90 percent, a figure the investigators describe as excellent. In oncology, adherence is often the quiet variable that determines whether a promising drug fulfills its potential, and myeloma patients, who are frequently elderly and burdened by other conditions, are particularly vulnerable to dose reductions, delays, and discontinuation. Sustaining more than nine in ten patients on an intensive proteasome inhibitor regimen suggests that, in routine German practice, carfilzomib-based therapy is manageable in a way that clinical concerns about toxicity had not always guaranteed.

The effectiveness data were equally encouraging and closely mirrored what randomized trials had predicted. Median progression-free survival, the length of time patients live without their disease worsening, reached 17.5 months for those receiving KRd, 13.4 months for those on Kd, and 20.1 months for those treated with the KdD combination that includes daratumumab. These confidence intervals, spanning for example 14.5 to 24.7 months for KRd and 10.9 to 26.6 months for KdD, indicate results statistically consistent with both prior randomized clinical trials and earlier real-world studies of the same regimens. In other words, the benefits observed under idealized trial conditions appear to translate faithfully to ordinary clinics.

Overall survival figures added further weight to the findings. Patients receiving KRd achieved a median overall survival of 38.9 months, while those on Kd reached 24.6 months. Most notably, the median overall survival for the KdD cohort had not yet been reached at the time of analysis, with the lower bound of the confidence interval at 21.9 months, meaning more than half of those patients were still alive when the data were locked. The addition of daratumumab to the carfilzomib and dexamethasone backbone appears to be driving some of the most durable outcomes in the study, consistent with the broader trend of antibody-based immunotherapy reshaping myeloma treatment.

Beyond the survival statistics, CARO also captured something that clinical trials often overlook: how patients actually feel during treatment. Using patient-reported outcome measures, the researchers found that quality of life remained stable throughout the course of therapy, a significant achievement for a population facing a relapsed or refractory cancer. Even more striking, pain parameters improved after six months of treatment. For myeloma patients, whose disease frequently attacks bone and causes debilitating pain, an improvement in this dimension represents a tangible, everyday benefit that no laboratory marker can capture. Stable quality of life combined with reduced pain suggests that the effectiveness of these regimens does not come at the cost of patient wellbeing.

The significance of CARO extends beyond its individual numbers. Real-world evidence studies like this one serve as a critical bridge between the controlled environment of drug registration trials and the heterogeneous reality of clinical practice, where patients may be older, frailer, or have comorbidities that would have excluded them from pivotal studies. By demonstrating that adherence exceeds 90 percent and that effectiveness aligns with trial data across 69 diverse German sites, CARO provides reassurance that the promise of carfilzomib-based therapy holds up outside the spotlight of academic trial centers. This matters for treatment guidelines, for reimbursement decisions, and ultimately for the conversations oncologists have with patients weighing their options after relapse.

The study also reflects the collaborative infrastructure that makes such research possible. CARO was managed and analyzed by iOMEDICO, a research organization based in Freiburg, and received partial financial support from Amgen, the manufacturer of carfilzomib. Importantly, the company had no role in study design, data collection and analysis, interpretation of results, the decision to publish, or preparation of the manuscript, an arrangement intended to safeguard the independence of the findings. The investigator team spanned community practices and university hospitals across Germany, led by researchers including Karin Potthoff of iOMEDICO, with Monika Engelhardt of the University of Freiburg and Wolfgang Knauf of the Centrum für Hämatologie und Onkologie Bethanien in Frankfurt serving as shared senior authors.

For the myeloma community, the final CARO results land at a moment of rapid therapeutic evolution. Proteasome inhibitors like carfilzomib, immunomodulatory agents like lenalidomide, and CD38-directed antibodies like daratumumab now form the backbone of relapsed treatment strategies, and newer options continue to emerge. What CARO demonstrates is that these tools, deployed in the real world by real physicians treating real patients, deliver clinically meaningful outcomes: progression-free survival approaching or exceeding a year and a half in the stronger cohorts, overall survival stretching toward or beyond three years, stable quality of life, and adherence rates that few intensive cancer regimens achieve. As the field moves toward ever more complex combination strategies, studies like CARO provide the ground truth against which future innovations must be measured, and they remind us that a drug’s true value is revealed not in the trial brochure but in the daily lives of the patients who take it.

Subject of Research: Real-world adherence, effectiveness, and quality of life with carfilzomib-based regimens in relapsed/refractory multiple myeloma

Article Title: Final results of the CARO study: real-world adherence, effectiveness and patient-reported quality of life with carfilzomib-based regimens in German patients with relapsed/refractory multiple myeloma

Article References: Potthoff, K., Uhlig, J., Heyde, E. V. D., Losem, C., Nusch, A., Ammon, A., Schöttker, B., Schulz, H., Janssen, J., Welslau, M., Wilop, S., Vannier, C., Hanselmann, J., Serrer, L., Woerner, S. M., Koszinowski, S., Engelhardt, M., & Knauf, W. (2026). Final results of the CARO study: real-world adherence, effectiveness and patient-reported quality of life with carfilzomib-based regimens in German patients with relapsed/refractory multiple myeloma. Annals of Hematology. https://doi.org/10.1007/s00277-026-07302-8

Image Credits: AI Generated

DOI: 10.1007/s00277-026-07302-8

Keywords: multiple myeloma, carfilzomib, KRd, daratumumab, real-world evidence, treatment adherence, progression-free survival, overall survival, quality of life, relapsed refractory myeloma, proteasome inhibitor, Germany