James R. Berenson

BACKGROUND: Bortezomib, a boronic acid dipeptide, is a novel proteasome inhibitor that has been shown in preclinical and phase 1 studies to have antimyeloma activity. METHODS: In this multicenter, open-label, nonrandomized, phase 2 trial, we enrolled 202 patients with relapsed myeloma that was refractory to the therapy they had received most recently. Patients received 1.3 mg of bortezomib per square meter of body-surface area twice weekly for 2 weeks, followed by 1 week without treatment, for up to eight cycles (24 weeks). In patients with a suboptimal response, oral dexamethasone (20 mg daily, on the day of and the day after bortezomib administration) was added to the regimen. The response was evaluated according to the criteria of the European Group for Blood and Marrow Transplantation and confirmed by an independent review committee. RESULTS: Of 193 patients who could be evaluated, 92 percent had been treated with three or more of the major classes of agents for myeloma, and in 91 percent, the myeloma was refractory to the therapy received most recently. The rate of response to bortezomib was 35 percent, and those with a response included 7 patients in whom myeloma protein became undetectable and 12 in whom myeloma protein was detectable only by immunofixation. The median overall survival was 16 months, with a median duration of response of 12 months. Grade 3 adverse events included thrombocytopenia (in 28 percent of patients), fatigue (in 12 percent), peripheral neuropathy (in 12 percent), and neutropenia (in 11 percent). Grade 4 events occurred in 14 percent of patients. CONCLUSIONS: Bortezomib, a member of a new class of anticancer drugs, is active in patients with relapsed multiple myeloma that is refractory to conventional chemotherapy.

BACKGROUND: Skeletal complications are a major clinical manifestation of multiple myeloma. These complications are caused by soluble factors that stimulate osteoclasts to resorb bone. Bisphosphonates such as pamidronate inhibit osteoclastic activity and reduce bone resorption. METHODS: Patients with stage III multiple myeloma and at least one lytic lesion received either placebo or pamidronate (90 mg) as a four-hour intravenous infusion given every four weeks for nine cycles in addition to antimyeloma therapy. The patients were stratified according to whether they were receiving first-line (stratum 1) or second-line (stratum 2) antimyeloma chemotherapy at entry into the study. Skeletal events (pathologic fracture, irradiation of or surgery on bone, and spinal cord compression), hypercalcemia (symptoms or a serum calcium concentration > or = 12 mg per deciliter [3.0 mmol per liter]), bone pain, analgesic-drug use, performance status, and quality of life were assessed monthly. RESULTS: Among 392 treated patients, the efficacy of treatment could be evaluated in 196 who received pamidronate and 181 who received placebo. The proportion of patients who had any skeletal events was significantly lower in the pamidronate group (24 percent) than in the placebo group (41 percent, P < 0.001), and the reduction was evident in both stratum 1 (P = 0.04) and stratum 2 (P = 0.004). The patients who received pamidronate had significant decreases in bone pain and no deterioration in performance status and quality of life. Pamidronate was tolerated well. CONCLUSIONS: Monthly infusions of pamidronate provide significant protection against skeletal complications and improve the quality of life of patients with stage III multiple myeloma.

In a phase 2 open-label study of the novel proteasome inhibitor bortezomib, 54 patients with multiple myeloma who had relapsed after or were refractory to frontline therapy were randomized to receive intravenous 1.0 or 1.3 mg/m(2) bortezomib twice weekly for 2 weeks, every 3 weeks for a maximum of eight cycles. Dexamethasone was permitted in patients with progressive or stable disease after two or four cycles respectively. Responses were determined using modified European Group for Blood and Marrow Transplantation criteria. The complete response (CR) + partial response (PR) rate for bortezomib alone was 30% [90% confidence interval (CI), 15.7-47.1] and 38% (90% CI, 22.6-56.4) in the 1.0 mg/m(2) (8 of 27 patients) and 1.3 mg/m(2) (10 of 26 patients) groups respectively. The CR + PR rate for patients who received bortezomib alone or in combination with dexamethasone was 37% and 50% for the 1.0 and 1.3 mg/m(2) cohorts respectively. The most common grade 3 adverse events were thrombocytopenia (24%), neutropenia (17%), lymphopenia (11%) and peripheral neuropathy (9%). Grade 4 events were observed in 9% (five of 54 patients). Bortezomib alone or in combination with dexamethasone demonstrated therapeutic activity in patients with multiple myeloma who relapsed after frontline therapy.

PURPOSE: To determine the efficacy and safety of 21 monthly cycles of pamidronate therapy in patients with advanced multiple myeloma. PATIENTS AND METHODS: Patients with stage III myeloma and at least one lytic lesion received either placebo or pamidronate 90 mg intravenously administered as a 4-hour infusion monthly for 21 cycles. At study entry, the patients were stratified according to whether they were to receive first-line (stratum 1) or second-line (stratum 2) antimyeloma chemotherapy. Skeletal events (pathologic fracture, radiation or surgery to bone, and spinal cord compression) and hypercalcemia were assessed monthly. RESULTS: The results of the first nine previously reported cycles are extended to 21 cycles. Of the 392 randomized patients, efficacy could be evaluated in 198 who received pamidronate and 179 who received placebo. After 21 cycles, the proportion of patients who developed any skeletal event was lower in the pamidronate-group (P = .015). The mean number of skeletal events per year was less in the pamidronate-group (1.3) than in placebo-treated patients (2.2; P = .008). Although survival was not different between the pamidronate-treated group and placebo patients overall, stratum 2 patients who received pamidronate lived longer than those who received placebo (14 v 21 months, P = .041). Pamidronate was safe and well tolerated during the 21 cycles of therapy. CONCLUSION: Long-term monthly infusions of pamidronate as an adjunct to chemotherapy are superior to chemotherapy alone in reducing skeletal events in stage III multiple myeloma patients, and may improve the survival of patients on salvage therapy.

PURPOSE: To determine the frequency, characteristics, and reversibility of peripheral neuropathy from bortezomib treatment of advanced multiple myeloma. PATIENTS AND METHODS: Peripheral neuropathy was assessed in two phase II studies in 256 patients with relapsed and/or refractory myeloma treated with bortezomib 1.0 or 1.3 mg/m2 intravenous bolus on days 1, 4, 8, and 11, every 21 days, for up to eight cycles. Peripheral neuropathy was evaluated at baseline, during the study, and after the study by patient-reported symptoms using the Functional Assessment of Cancer Therapy Scale/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) questionnaire and neurologic examination. During the study, peripheral neuropathy was also evaluated by investigator assessment. A subset of patients underwent nerve conduction studies (n = 13). RESULTS: Before treatment, 194 (81%) of 239 patients had peripheral neuropathy by FACT/GOG-Ntx questionnaire, and 203 (83%) of 244 patients had peripheral neuropathy by neurologic examination. Treatment-emergent neuropathy was reported in 35% of patients, including 37% (84 of 228 patients) receiving bortezomib 1.3 mg/m2 and 21% (six of 28 patients) receiving bortezomib 1.0 mg/m2. Grade 1 or 2, 3, and 4 neuropathy occurred in 22%, 13%, and 0.4% of patients, respectively. The incidence of grade > or = 3 neuropathy was higher among patients with baseline neuropathy by FACT/GOG-Ntx questionnaire compared with patients without baseline neuropathy (14% v 4%, respectively). In all 256 patients, neuropathy led to dose reduction in 12% and discontinuation in 5%. Of 35 patients with neuropathy > or = grade 3 and/or requiring discontinuation, resolution to baseline or improvement occurred in 71%. CONCLUSION: Bortezomib-associated peripheral neuropathy seemed reversible in the majority of patients after dose reduction or discontinuation. Although severe neuropathy was more frequent in the presence of baseline neuropathy, the overall occurrence was independent of baseline neuropathy or type of prior therapy.