Bortezomib Maintenance May Not Prolong PFS in Transplant-Ineligible Myeloma

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.”

Reference

1. 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]