Safety, Tolerability, and Pharmacology of Bortezomib in Cancer Patients with Renal Failure Requiring Dialysis: Results from a Prospective Phase 1 Study.

Background: Bortezomib (btz; VELCADE®) is a specific, reversible proteasome inhibitor approved for the treatment of patients (pts) with multiple myeloma (MM) and mantle cell lymphoma following at least one prior therapy. Retrospective analyses of phase 2/3 studies and case series have shown btz alone or in combination is active and tolerable in MM pts with various degrees of renal impairment, including pts on dialysis. We previously reported clinical and pharmacologic data from the first prospective, dose-escalating study of btz in adult cancer pts with various degrees of renal impairment (ASCO 2006, abstract 2032). Here we present updated safety and tolerability data for dialysis-dependent patients.

Methods: Pts with advanced cancer were stratified by renal function into controls and four groups ranging from mild impairment to dialysis dependence. Pts received btz on d 1, 4, 8, and 11 of a 21-day cycle; dose escalation (0.7, 1.0, 1.3 mg/m²) proceeded in cohorts of 3 pts based on dose limiting toxicities (DLTs) observed in cycle 1. Blood samples were taken on d 1 and 8 of cycle 1 for pharmacokinetic (PK) and pharmacodynamic (PD) analysis. Adverse events (AEs) were evaluated using NCI CTC v2.0. DLTs were grade 4 neutropenia for ≥7 d or neutropenic fever, grade 4 thrombocytopenia for ≥7 d, grade 4 hemoglobin for ≥7 d, and grade ≥3 non-hematologic toxicity.

Results: To date, 59 pts have been treated, including 16 controls, 34 pts with mild-to-severe impairment, and 9 dialysis pts. Among dialysis pts: 3 were treated at 0.7, 2 at 1.0, and 4 at 1.3 mg/m²; median age was 62 y (range: 42–74); tumor types were MM (n=4), follicular lymphoma (n=1), and solid tumors (n=4). Median number of treatment cycles received was 2 in controls and across renal impairment groups. Dialysis pts received a median of 2 treatment cycles (range: 1–4); 1 pt remains on therapy. Dose escalation was well tolerated, with no DLTs, in pts with mild-to-severe renal impairment. There were no DLTs in cycle 1 in dialysis pts. Toxicities were generally mild in all groups. Among dialysis pts, no unexpected toxicities were seen. One grade 4 treatment-related AE (elevated creatinine) has been reported; grade 3 treatment-related AEs include platelets/thrombocytopenia (3 pts), diarrhea, hemoglobin, leukopenia, lymphopenia, packed red blood cell transfusion, sensory neuropathy, and vomiting (1 pt each). The overall AE profile in dialysis pts was similar to that in controls and in pts with mild-to-severe impairment, although renal and metabolic AEs appeared more common in dialysis pts.

Conclusions: Btz at doses up to 1.3 mg/m² on this schedule was well tolerated in pts with advanced malignancies with mild-to-severe renal impairment and dialysis dependence. PK and PD analyses for dialysis pts treated at 1.3 mg/m² will be reported. Btz is a viable treatment option for pts requiring dialysis.