Safety and efficacy results from an international Expanded Access Programme to bortezomib for patients with relapsed and/or refractory multiple myeloma: A subset analysis of the Australian and New Zealand data of 111 patients

Background: Bortezomib has been shown to be a safe and efficacious for the treatment of relapsed and refractory multiple myeloma (MM). Here we report a subset analysis of Australian and New Zealand data from the International Extended Access Programme for bortezomib. Methods: Patients with more than or equal to two prior lines of therapy were given bortezomib 1.3 mg/m ² (i.v. bolus days 1, 4, 8, 11) for up to eight 21-day cycles (C). Dexamethasone, 20 mg/day p. o. on the day of, and day after, bortezomib was added after C2 for progressive disease or after C4 for stable disease. Efficacy was assessed using modified Southwest Oncology Group criteria in the intent-to-treat group. Results were compared between the Australian and New Zealand and international cohort. Results: One hundred and eleven patients from 16 centres (55% men, median age 61.9 years) had a median of 5.2 ± 2.8 treatment cycles of bortezomib. Among them, 82% had ≥3 prior therapies. Grade 3-4 treatment-related adverse events were reported in 57 patients (52%); the most common were thrombocytopenia (25.7%), anaemia (8.3%), peripheral neuropathy (7.3%) and diarrhoea (7.3%). Responses were evaluable in 106 patients: 22% achieved a best response of complete response/response and 20% partial response (overall response rate of 42%). Median times to first and best responses were 42 days and 69 days, respectively. Compared with the international cohort, the cohorts from Australian and New Zealand showed inferior overall response rates (54 vs 42%, P = 0.001), possibly due to heavier pretreatment (82% greater than or equal to three prior therapies vs 68%, P < 0.001). Conclusion: Our analysis confirms that bortezomib is safe and effective in relapsed and refractory MM in a real-life clinical setting.