Bortezomib subcutaneous injection in combination regimens for myeloma or systemic light-chain amyloidosis: a retrospective chart review of response rates and toxicity in newly diagnosed patients.

BACKGROUND: Bortezomib is a first-in-class proteasome inhibitor approved by the US Food and Drug Administration for the treatment of all phases of multiple myeloma (MM) and it is also used for the treatment of [corrected] light-chain amyloidosis (AL). The subcutaneous formulation of bortezomib was approved in 2012 based on data from Phase III studies in patients with relapsed MM.

OBJECTIVE: This article reports experience with subcutaneous bortezomib in patients with newly diagnosed MM or AL in a tertiary care center.

METHODS: This retrospective study analyzed data from all patients newly diagnosed with MM or AL and treated at our center between April 1, 2011, when the hospital pharmacy approved and implemented the option of subcutaneous bortezomib, and April 1, 2013. Patients who received subcutaneous bortezomib as a part of the first line of therapy were identified through the pharmacy's database. Data were abstracted from electronic medical records, and data on demographic characteristics, disease profiles, toxicities, responses, and survival were collected.

RESULTS: Data from 29 patients (MM, 16; AL, 13; 62% male; median age, 66 years [range, 46-84]) were analyzed. Ninety percent of patients received cyclophosphamide, bortezomib, and dexamethasone (CyBorD) as the first line of treatment. None of the patients developed grade 3/4 peripheral neuropathy, whereas 1 patient experienced grade 3 diarrhea, and 2 patients developed grade 3 thrombocytopenia requiring dose reductions. The overall response rate was 93%, with 59% of patients achieving very good partial response or complete response.

CONCLUSIONS: With the use of subcutaneous bortezomib in combination regimens in patients with newly diagnosed MM or AL, there was a high overall response rate and minimal toxicity. These results are consistent with the findings from prior studies and provide a basis for further studies comparing new proteasome inhibitors to subcutaneous bortezomib in combination regimens for patients with newly diagnosed MM or AL.