Most patients with multiple myeloma did not adhere to lenalidomide therapy, according to data from a retrospective single-center study that assessed treatment adherence to the immunomodulatory agent 1 year from lenalidomide initiation. These findings were published in the Journal of Oncology Pharmacy Practice.
The study comprised 81 patients with multiple myeloma from an Italian hospital who started lenalidomide treatment between January 1, 2012, and June 30, 2016. Patients were considered to adhere to therapy if they took the medication at least 80% of time. “It is generally accepted that the threshold-value of medication adherence that distinguishes an adherent from a non-adherent patient is 80%; as a result, a loss of 20% of adherence is tolerable in order to obtain a clinical response,” the study authors stated.
Only 26 patients (32%) adhered to lenalidomide treatment at least 80% of the time, which included 5 patients who were “completely adherent” to therapy and took 100% of their doses. Most patients, however, were not adherent to treatment. This included 4 patients who adhered less than half of the time, 11 between 51% and 60% of the time, 22 between 61% and 70% of the time, and 18 between 71% and 80% of the time. Adherence rates were similar across patient subgroups.
“The fact that there are no differences between sample subgroups means that adherence rates do not depend on variables related to patient characteristics, but are common to all patients with multiple myeloma treated with lenalidomide,” the study authors explained, adding that it is “concerning” that adherence rates above 80% were found in so few patients. “It is necessary to investigate and further delve into the causes of lack of adherence, conceivably to be related more to tolerability than dosage,” they said.
Clinical outcomes were also evaluated at 1 year of lenalidomide treatment, and among 5 variables evaluated, only treatment adherence was significantly associated with overall survival (P =0.041). Treatment adherence was not associated with progression-free survival or clinical response.
The study authors acknowledged that the study did have limitations, one of which was the inability to describe the causes of non-adherence.
Santoleri F, Lasala R, Ranucci E, et al. Adherence to and effectiveness of lenalidomide after 1 year of treatment in a real world setting. J Oncol Pharm Pract. Published online December 22, 2020. doi:10.1177/1078155220980807