Using Treatment-Free Interval to Assess Response to Multiple Myeloma Therapy
Posted: Friday, May 8, 2020
The objective for patients with transplant-ineligible multiple myeloma should be to maximize the benefit of first-line treatment, as first-line therapy results in the longest treatment-free interval, which progressively decreases with subsequent therapies. Faouzi Djebbari, MPharm, MSc, of Oxford University Hospitals, United Kingdom, and colleagues published their study findings in PLOS ONE.
“In view of the recent shift towards continuous therapy, we looked to evaluate the treatment-free interval as an additional metric of efficacy in routine practice, after first and subsequent lines of therapy,” noted the authors. “When continuous therapy is not appropriate due to patient choice or toxicities, an efficacious (not limited to thalidomide or bortezomib) but tolerable fixed-duration therapy strategy...remains a reasonable alternative approach.”
Patients included in this study were treated in the Thames Valley Cancer Network from 2009 to 2017 and had newly diagnosed multiple myeloma. This cohort was composed of 292 patients who were given a variety of first-line agents including thalidomide (61%), bortezomib (22%), alkylator-based therapy (10%), and lenalidomide-based therapy (7%).
The median treatment-free interval was longest after the first therapy at 6.9 months, which decreased to 1.8 months after second-line therapy and 0.6 months after third-line treatment. The overall response rate to first-line therapy was 67%, with 21% of patients achieving a complete response, 18% having stable disease, and 8% experiencing disease progression. The median overall survival for the cohort was 30.2 months, and progression-free survival was 9 months.
On subgroup analysis, patients older than age 75 had a significant reduction in overall survival compared with younger patients (22.4 vs. 49.0 months, respectively). The median overall survival was also reduced in patients with worsening comorbidities. Those with mild comorbidities had an overall survival of 52.4 months, compared with 24.0 months in patients with severe comorbidities.
Disclosure: For the full list of authors’ disclosures, visit journals.plos.org.
