Biweekly bortezomib maintenance therapy for 1 year may not improve clinical outcomes among transplant-ineligible patients with multiple myeloma (MM) who plateau after bortezomib induction therapy, according to a study published in the International Journal of Hematology.1
For this non-comparative phase 2 study, 38 patients with previously untreated MM who were ineligible for autologous stem cell transplantation (ASCT) were treated with a bortezomib-containing induction regimen until plateau. Patients then initiated maintenance treatment with bortezomib 1.3 mg/m2 every 2 weeks for 1 year within 60 days of completing induction therapy.
Of 36 evaluable patients, the overall response rate (ORR) was 61%. There was, however, no improvement in the depth of response during the maintenance phase, and 50% of patients experienced disease progression. After completing the 1-year maintenance therapy, 1 patient had a stringent complete response, 2 patients had a very good partial response, 3 patients had a partial response, and 3 patients had stable disease.
The median duration of induction and maintenance therapy was 5.9 months and 10.3 months, respectively, and median progression-free survival (PFS) from the start of induction therapy was 13.8 months and 10.7 months from maintenance therapy. After a median follow-up of 30.7 months, median overall survival from induction therapy initiation had not been reached.
Thirty-five percent of patients receiving maintenance therapy experienced at least 1 treatment-related adverse event (AE). Grade 3 leukopenia and thrombocytopenia occurred in 2 patients; other AEs included sensory neuropathy, diarrhea, constipation, nausea, fatigue, and pruritus.
The authors concluded that “a ‘plateau-oriented induction approach’ is inadequate in the era of bortezomib. Further investigations are also warranted to maintain a durable efficacy and avoid any treatment-related toxicity in elderly MM patients with either stable or responsive disease after bortezomib induction therapy.”
- Isoda A, Murayama K, Ito S, et al. Bortezomib maintenance therapy in transplant-ineligible myeloma patients who plateaued after bortezomib-based induction therapy: a multicenter phase II clinical trial. Inter J Hematol. 2018 Mar 28. doi: 10.1007/s12185-018-2448-9 [Epub ahead of print]