(058) First-line therapy discontinuation among Brazilian multiple myeloma patients: incidence and reasons

Background: Multiple myeloma (MM) is an incurable hematological cancer. Regardless the eligibility for stem cell transplant, multiples lines of treatment with anti-myeloma drugs are needed to promote disease remission and increase patient survival.

Objectives: To evaluate the incidence and reasons for discontinuation of first-line therapy in outpatients with MM who started therapy in Belo Horizonte, Brazil from 2009 to 2020.

Methods: Historical cohort study of treatment-naïve MM patients followed from initiation of treatment until discontinuation of first-line therapy. Discontinuation of first-line therapy was characterized as i) discontinuation followed by a second-line therapy, and ii) discontinuation that prevented patients from receiving a subsequent line of treatment. The cumulative incidence of discontinuation followed by a second-line therapy was estimated using non-parametric competing risk analysis with 95% confidence intervals. The probability of discontinuation followed by second-line treatment was compared according to selected variables using the Gray’s test at a significance level of 5%.

Results: In total, 260 patients participated in the study. Approximately half of the patients were female and younger than 65 years. Discontinuation of first-line therapy followed by a second-line therapy accounted for 50.4% of the patients and occurred up to 30th month. The main reason for discontinuation not qualifying patients for receiving second-line therapy was to achieve a response to treatment. The maximum times for discontinuation not followed by a second-line therapy ranged from 12 to 20 months due to deaths and response to treatment, respectively. The probability of receiving second-line therapy was higher among patients initiating therapy in 2009-2014 and those who were not transplanted.

Conclusions: Discontinuation of first-line therapy followed by second-line treatment occurred as likely as the discontinuation not followed by a subsequent line. Our findings should contribute to prevention and management of discontinuation for modifiable reasons relevant for clinical practice.