LAUSR

The combination of bortezomib, cyclophosphamide and dexamethasone (CyBorD or VCD) has been evaluated using different protocols in multiple myeloma (MM). Most of these studies employed twice weekly bortezomib at 1.3 mg/m (days 1, 4, 8, 11) and intravenous (IV) administration [1–6]. Subcutaneous (SC) bortezomib has been demonstrated to be associated with non-inferior efficacy and less adverse events than IV administration [1, 7] and weekly rather than twice weekly administration of bortezomib is associated with reduced toxicity with similar response rates [2, 7, 8]. In light of this, weekly SC bortezomib CyBorD protocols are used widely in Australia, the United Kingdom and Europe as induction prior to autologous stem cell transplantation (ASCT) [9, 10]. However, there is a lack of published data regarding response rates and survival outcomes utilising these regimens. We aimed to evaluate the experience of using a weekly CyBorD protocol as induction prior to ASCT in two transplant centres in Australia. This is a retrospective study of patients treated between August 2015 and August 2019 at St Vincent’s Hospital and January 2012 and August 2019 at Liverpool Hospital in Sydney, Australia. These dates were selected based on availability of electronic medical records, in addition to the timing of adoption of this protocol at these sites. All patients prescribed four 28-day cycles of CyBorD (weekly SC bortezomib 1.3 mg/m, oral cyclophosphamide 300 mg/m (or 500 mg) and dexamethasone 40 mg) for newly diagnosed MM with an intent to proceed to ASCT were included. Patients were identified from prescribing records and the ASCT registry. This project was approved by the South Western Sydney Local Health District Human Research Ethics Committee. Survival analysis was performed using Prism 8 Kaplan–Meier analysis. Seventy patients were identified. Median age of patients was 60 (range 31–73), and 66% were male. Sixty-nine of seventy patients had a diagnosis of MM, and one patient had plasma cell leukaemia. Myeloma International Staging System (ISS) could be calculated in 61 patients: 33 had Stage I, 15 had Stage II and 13 had Stage III disease. Myeloma Revised International Staging System (R-ISS) could be calculated in 58: 30 had Stage I, 21 had Stage II and 7 had Stage III disease. Sixtyfive patients had cytogenetics available: 49 had standard risk and 17 had high-risk cytogenetics, including 1 ‘double’ hit, as defined by the mSMART risk stratification system [10]. Most patients received therapy as planned (62/70) and all but one proceeded to ASCT. Seven patients had additional therapy after four cycles of CyBorD due to inadequate response: additional cycles of CyBorD (n= 3), thalidomide (n= 2) and lenalidomide/dexamethasone (n= 2). Best response to CyBorD induction included stable disease (SD) in 16 (23%) partial response (PR) in 30 (43%), and a ≥very good partial response (VGPR) in 24 (33%) (two complete response (CR)). No patient had progressive disease (PD). One patient with non-secretory disease had complete resolution of radiological findings. Of those who had SD, R-ISS * Georgia J. McCaughan [email protected]