Treatment of Patients with Multiple Myeloma Complicated by Renal Failure with Bortezomib - Based Regimens.

Introduction: Renal failure is a common feature of multiple myeloma and a major management problem. There is limited data regarding the reversibility of renal failure, the kinetics of serum creatinine and the safety of novel agents, such as bortezomib, when administered to newly diagnosed or relapsed/refractory patients with renal failure. The purpose of our analysis was to assess the frequency of renal failure improvement and kinetics of serum creatinine in patients who received bortezomib-based regimens.

Patients and methods: We evaluated 20 consecutive patients with newly diagnosed (n=7) or relapsed/refractory (n=13) multiple myeloma and renal failure, defined as a serum creatinine ≥ 2mg/dl. Patients’ median age was 66 years (range 43–88 years). Median serum creatinine was 3.8 mg/dl (range 2–11.9 mg/dl) and median creatinine clearance was 15.3 ml/min (range 6.4–33.3). Other features included hemoglobin <10gr/dl in 12 patients, platelets <100 × 10⁹/l in 3 patients and elevated serum LDH in 9 patients. All patients received bortezomib plus dexamethasone alone or in combination with other agents, such as thalidomide, doxorubicin or melphalan. Reversibility of renal failure was defined as a sustained decrease of serum creatinine to <1.5 mg/dl and renal response was defined as ≥50% decrease of serum creatinine from its peak value.

Results: Reversal of renal failure was documented in 35% of all patients and the median time to reversal was 23 days. Moreover, 9 patients (45%) had 50% decrease in serum creatinine and the median time to decrease was 34 days. Some decrease of creatinine was documented in 88% of patients. Among four patients who were on renal dialysis, 2 became independent of this procedure after the second and the third cycle of treatment. The objective response rate was 61% and the median progression free survival for responders was 12 months. Toxicities were similar to those seen in myeloma patients without renal failure who were treated with bortezomib-based regimens. Grade 3–4 neutropenia and thrombocytopenia were seen in 28% and 22% of patients respectively. One patient died of infection and bortezomib had to be discontinued in 4 patients due to grade III neurotoxicity.

Conclusions: When bortezomib-based regimens are administered to myeloma patients with renal impairment their toxicity and efficacy are similar to those observed in patients with normal renal function. Moreover, these regimens are associated with rapid improvement of renal function in most patients and with reversal of renal failure in one-third of them.