Patients with transplant-ineligible newly diagnosed multiple myeloma (NDMM) have better overall survival and progression free survival with continuous lenalidomide and low-dose dexamethasone compared to fixed duration front line regimens, real-world data shows.

The retrospective trial compared the outcomes of NDMM patients within the UK Thames Valley Cancer Network who received one cycle of fixed duration therapy (FDT) outside a clinical trial with age-and ISS stage-matched patients who received continuous treatment with lenalidomide and low-dose dexamethasone (Rd) as part of the MM-020 trial.

In the FDT cohort the most common frontline therapies included thalidomide (66%) or proteasome inhibitors (PI, 24%) and the most commonly used combinations were attenuated cyclophosphamide, thalidomide, and dexamethasone (35%) and cyclophosphamide, thalidomide, and dexamethasone (CTDa, 21%).

Results showed that median overall survival (OS) was significantly shorter in the FDT cohort than in the MM-020 trial-derived continuous cohort (30.3 vs. 58.6 months; p < 0.0001); and 5-year OS was lower (27% vs. 47%).

Median progression free survival (PFS)  and time to next therapy (TTNT) were significantly shorter in the FDT cohort (9.0 vs. 25.7 months; p < 0.0001 and 16.7 vs. 42.2 months; p < 0.0001, respectively); after five years, more patients in the FDT cohort had progressed to second-line treatment (94% vs. 61%).

“These data further support that Rd continuous treatment helps provide sustained disease control … delaying disease progression may be particularly beneficial for older transplant-ineligible NDMM patients who may not respond to further therapy at first relapse, or who do not have the opportunity to receive multiple lines of treatment due to cumulative adverse events and/or comorbidities,” the researchers wrote in a letter published in Leukemia and Lymphoma.

They conceded that the study had limitations, namely that it compared real-world patients on FDT with patients on Rd continuous in an RCT that mandated exclusion and data-censoring criteria.

“Although the results of such a comparison should be interpreted with caution, we note that the median OS and PFS in the FDT cohort (30.3 and 9.0 months, respectively) are in line with those reported for CTDa in a large RCT, where median OS and PFS were 33.2 and 13.0 months, respectively,” they wrote.

The study was funded by Celgene, who make lenalidomide.