Daratumumab: A Promising Retreatment Option for Myeloma Patients

Introduction

Daratumumab (Darzalex) has shown promise not only in initial treatments but also as a viable option for retreatment in patients with relapsed or refractory multiple myeloma. This breakthrough was discussed in detail during the 2024 ASCO Annual Meeting.

Study Overview

The study was a retrospective examination involving 157 patients who received daratumumab-based regimens between January 1, 2015, and December 31, 2023. These patients were treated either initially or retreated with daratumumab, and their responses were evaluated according to the International Myeloma Working Group Response Criteria.

Response Rates

The response rates were closely monitored, showing 52% overall response rate (ORR) in the initial treatment (D1) and 54% ORR for retreatment (D2). Notably, the study showed similar response rates even in patients who were refractory to daratumumab previously.

Importance of Retreatment

One of the key findings was that daratumumab retreatment yielded comparable results to initial treatment. This finding is crucial, especially for patients who have limited options after becoming refractory to initial treatments. Therefore, daratumumab remains a highly effective option in subsequent lines of therapy.

Demographics and Patient Profiles

The median age of patients was 67 years, with a fairly balanced gender distribution. Most participants were White (71%), followed by Black (17%), Asian (6%), and those of unknown race (6%). The majority had a standard cytogenetic risk (67%), while the rest had a high risk (33%).

Lines of Therapy

The study found differences between initial and retreatment phases in terms of therapy regimens. For instance, 32% of patients in the D1 phase received monotherapy with daratumumab, compared to only 4% in the D2 phase. The use of immunomodulatory agents alongside daratumumab was more consistent between the groups.

Progression-Free Survival

The median progression-free survival (PFS) during daratumumab retreatment was 10.8 months, with a median follow-up of 53.9 months. The overall survival median was 47.4 months, indicating the longevity benefits of using daratumumab in retreatment.

Subgroup Analysis

Subgroup analyses highlighted differences based on the number of lines of therapy patients had received. Patients who received fewer than four lines of therapy had a median PFS of 16.53 months compared to 7.62 months for those who received more lines of therapy.

Timing Between Treatments

Another intriguing aspect was the time interval between treatments. Patients with a retreatment interval of fewer than 180 days showed better median PFS (16.1 months) compared to those with intervals longer than 180 days (9.46 months).

Conclusion

Daratumumab remains an effective treatment option for multiple myeloma, even for those who have previously been refractory to it. The study's insights emphasize the importance of considering retreatment options with daratumumab, given its consistent performance in improving response and survival rates.