A phase I study of samarium lexidronam/bortezomib combination therapy for the treatment of relapsed or refractory multiple myeloma.

PURPOSE: This open-label, phase I dose-escalation study assessed the safety, tolerability, and initial efficacy of Samariam 153 (153Sm)-lexidronam/bortezomib combination therapy for patients with relapsed/refractory multiple myeloma. EXPERIMENTAL DESIGN: Patients were enrolled in six cohorts and given bortezomib (1.0 or 1.3 mg/m2) on days 1, 4, 8, and 11 and 153Sm-lexidronam (0.25, 0.5, or 1.0 mCi/kg) on day 3 of a 56-day cycle (maximum of four cycles). The primary endpoints were safety and tolerability of the 153Sm-lexidronam/bortezomib regimen. RESULTS: Twenty-four patients were enrolled. Median values for age, time since diagnosis, and number of prior treatments were 63 years, 29 months, and three regimens, respectively. The most common toxicities were hematologic; during the first cycle, median neutrophil and platelet nadirs were 1,000/mm3 and 98,500/mm3, respectively, and observed generally 3 to 4 weeks post-treatment. The incidences of grade 4 neutropenia and thrombocytopenia were 12.5% and 8.3%, respectively, during treatment cycle 1. Dose-limiting toxicity, reached in cohort 6 as a result of hematologic toxicity, defined the maximum tolerated dose as 0.5 mCi/kg 153Sm-lexidronam in combination with 1.3 mg/m2 bortezomib. The maximum tolerated dose for 153Sm-lexidronam in combination with the 1.0 mg/m2 bortezomib was not reached. No nonhematologic dose-limiting toxicities were observed; both the incidence and the severity of peripheral neuropathy were low. Responses occurred in 5 (21%) patients, including 3 (12.5%) complete and 2 (8.3%) minimal responses. CONCLUSIONS: Bortezomib combined with 153Sm-lexidronam appears to be a well-tolerated regimen, which showed clinical activity in this phase I trial for patients with relapsed or refractory multiple myeloma.

Bortezomib, ascorbic acid and melphalan (BAM) therapy for patients with newly diagnosed multiple myeloma: an effective and well-tolerated frontline regimen.

BACKGROUND: We conducted a single-arm, multicentre phase 2 study to evaluate bortezomib, ascorbic acid and melphalan (BAM) for patients with newly diagnosed multiple myeloma (MM). METHODS: Induction consisted of up to eight 28-d cycles of bortezomib 1.0 mg/m(2) on days 1, 4, 8 and 11, plus oral ascorbic acid 1 g and oral melphalan 0.1 mg/kg on days 1-4, followed by maintenance bortezomib 1.3 mg/m(2) every 2 wk until progression. RESULTS: Among 35 patients enrolled (median age 70 yr), responses occurred in 23/31 evaluable patients (74%) including five (16%) complete, three (10%) very good partial, six (19%) partial and nine (29%) minimal responses. Six patients (19%) had stable disease. Thus, disease control was achieved in 29 (94%) patients. Median times to first and best responses were 2 and 3 months (ranges 1-5 and 1-7), respectively. Median time to progression was 19 months and median overall survival has not been reached (range 2-23+ months). Grade 3 and 4 adverse events occurred in 17 and 5 patients, respectively; the most common were neutropenia, neuropathy and thrombocytopenia. CONCLUSIONS: BAM is an efficacious, well-tolerated and steroid- and immunomodulatory drug (IMiD)-free frontline treatment regimen for MM patients.