Real-World Patient Characteristics and Treatment Outcomes for Multiple Myeloma in Dreamm-7 and Dreamm-8 Cohorts in Finland

Introduction: Belantamab mafodotin (belamaf) is a novel treatment option for advanced multiple myeloma (MM), for which numerous clinical trials are ongoing. This population-based study aimed to describe the characteristics and treatment outcomes of MM patients, reflecting the inclusion criteria of DREAMM-7 and DREAMM-8 trials, providing insights into the current treatment practices and survival in Finnish real-world (RW) settings.

Methods: This observational RW study included DREAMM-7 and DREAMM-8 like MM patients in Finland between 2013 and 2022. The cohort of incident and adult MM patients was identified from the Hospital Districts of Helsinki and Uusimaa, and Southwest Finland. Data on specialized healthcare was collected from the data lakes of the hospital districts, and data on reimbursed drug purchases was retrieved from the Finnish Social Insurance Institution. The main inclusion criteria in both cohorts in this study, which were the same as those of the DREAMM-7 and DREAMM-8 trials, were to have at least one prior line of therapy and not to be intolerant/refractory to bortezomib. The DREAMM-7-like cohort also required the patients not intolerant/refractory to daratumumab and isatuximab, and the possible ASCT had to be received before the inclusion. The DREAMM-8-like cohort required patients to have received a prior lenalidomide (LEN)-containing regimen. The index date was set to the start of the next treatment line after meeting these inclusion criteria, and patients were followed up until death or end of study (EOS; Dec 31, 2022), whichever occurred first. Overall survival (OS) was analyzed with Kaplan-Meier method as time from index to death (event) or EOS (censoring). The progression dates were not available in the RW dataset. Thus, time to next treatment (TTNT) was used as a proxy for progression-free survival and was defined as time from index until the start of the next treatment line/death (event) or EOS (censoring).

Results: We identified 1,226 patients diagnosed with MM who had received first-line therapy between 2013 and 2022. Out of these, 447 patients (36.5%) met the criteria of the DREAMM-7-like cohort with a median follow-up of 20.8 months (interquartile range; IQR: 8.4, 39.4) and 196 patients (16.0%) the criteria of the DREAMM-8-like cohort with a median follow-up of 14.3 months (IQR: 6.9, 28.7). In the DREAMM-7-like cohort, median age was 72.0 years (IQR: 66.3-77.3), median time from MM diagnosis was 14.8 months (IQR: 6.4, 21.7), 91.4% had only one prior line of therapy, and 111 patients (28.0%) had received ASCT. The most used treatments after index date were LEN ± steroids (25.7%) and LEN with bortezomib ± steroids (22.9%). The median OS was 38.9 months (95% CI: 33.7-45.2), and the median TTNT was 15.3 months (95% CI: 12.9-17.9). In the DREAMM-8-like cohort, the median age was 70.8 years (IQR: 63.6, 77.0), the median time from MM diagnosis was 29.6 months (IQR: 16.5, 44.0), 48.0% had only one prior line of therapy, and 82 patients (41.8%) had received ASCT. In this cohort, treatment choices varied notably, with LEN with ixazomib ± steroids (9.7%) and LEN ± steroids (8.2%) being the most common. The median OS was 28.4 months (95% CI: 21.5-35.4), and the median TTNT was 9.9 months (95% CI: 7.6-11.4).

Conclusions: This RW study utilizing data from two Finnish hospital districts suggests that the outcomes of MM patients in second and later treatment lines, and of whom the majority had not received ASCT, appear rather limited. The median TTNT in our DREAMM-7 and 8-like cohorts were shorter than the median PFS of the belamaf arm in the DREAMM-7 and 8 trial (Hungria V., et al., NEJM, 2024, Dimopoulos M.A., NEJM, 2024). However, any comparisons of the outcomes between RW data and the corresponding clinical trials should be made cautiously. Firstly, our study included patients at the earliest possible time point after fulfilling the inclusion criteria, and no matching of the baseline characteristics with the clinical trials was performed. Secondly, the treatment landscape in MM is evolving rapidly, and the latest changes and their impact on survival were not captured in this study ending at the end of 2022. Nonetheless, the results highlight the need for more effective treatment options to improve survival of MM patients.

Vikkula:Medaffcon Oy: Current Employment. Lievonen:GSK: Other: Funding from GSK to Helsinki University Hospital hematological research group (HUCS institute) including investigator fees. Simin:Medaffcon Oy: Current Employment. Utriainen:GSK: Current Employment. Tikka:GSK: Current Employment, Current equity holder in publicly-traded company. Remes:GSK: Consultancy.