Results of a phase 3 trial in transplant-ineligible patients 65 years of age or older with newly diagnosed multiple myeloma (MM) showed that the addition of clarithromycin to lenalidomide with dexamethasone (Rd) did not improve progression-free survival (PFS). Study results were reported in the Blood Cancer Journal.

This multicenter clinical trial ( Identifier: NCT02575144) occurred across 20 centers in Spain and 1 in the US. This study enrolled patients with newly diagnosed MM who were 65 years of age or older and ineligible for autologous stem cell transplantation. Patients were randomized 1:1 to receive either Rd with clarithromycin (C-Rd group; 143 patients) or Rd without clarithromycin (Rd group; 143 patients). Progression-free survival (PFS) was the primary study endpoint.

The median study follow-up was 19 months (range, 0-54), and the median durations of treatment were 15.0 months for the C-Rd group and 15.9 months for the Rd group. The median age of the total population was 76 years (range, 65-93), with 56.6% of patients being 75 years of age or more. By data cutoff, treatment discontinuation was reported in 75.5% of the C-Rd group and in 57.3% of the Rd group.

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Patients in the C-Rd group showed a higher rate of complete response (CR) or better (22.6%) than the Rd group did (14.4%; P =.048). However, the median PFS was not significantly different between groups, at 23 months in the C-Rd group and 29 months in the Rd group (P =.14). The 19-month PFS rates were 53.4% in the C-Rd group and 61.9% in the Rd group. Rates of undetectable minimal residual disease were not significantly different between evaluated patients who achieved CR in each group, at 27% for the C-Rd group and 36% for the Rd group.

Grade 3 or 4 neutropenia occurred in 12% of the C-Rd group and in 19% of the Rd group. Grade 3 or 4 infections were reported in 30% of patients in the C-Rd group and in 25% of the Rd group. Fatal adverse events occurred in 25% of patients in the C-Rd group and in 15% of patients in the Rd group.

“In conclusion, the addition of clarithromycin to Rd in transplant ineligible newly diagnosed MM patients is not associated with an improved PFS,” the study investigators wrote in their report, noting that this was in spite of a higher CR rate versus Rd. They attributed this result to the greater proportion of fatalities associated with toxicity in the C-Rd group.

Disclosures: Some authors have declared affiliations with or received grant support from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.


Puig N, Hernandez MT, Rosiñol L, et al. Lenalidomide and dexamethasone with or without clarithromycin in patients with multiple myeloma ineligible for autologous transplant: a randomized trial. Blood Cancer J. 2021;11(5):101. doi:10.1038/s41408-021-00490-8