Tolerability of Velcade (Bortezomib) subcutaneous administration using a maximum volume of 3 mL per injection site

Subcutaneous injection is now commonly used as a standard for bortezomib administration. The bortezomib (Velcade(®)) product monograph recommends that intravenous injections be prepared at a concentration of 1 mg/mL, while subcutaneous injections may be prepared at a concentration of 2.5 mg/mL. Many institutions and subcutaneous administration guidelines use 2 mL as the maximum volume for subcutaneous injection. Using 2 mL as the maximum volume for injection would mean that many patients receiving bortezomib will receive two injections during each visit with common dosing parameters. In this prospective study evaluating a change to subcutaneous administration, bortezomib 1 mg/mL was administered subcutaneously at a higher maximum of 3 mL per injection site. For 57 individual patients, 339 doses were administered. Skin reactions were noted in 42% with all reactions being Grade 1 or 2. Patients tolerated subcutaneous injections well and only four patients were switched back to intravenous route. This is the first time that subcutaneous bortezomib of a volume up to a maximum of 3 mL (bortezomib 3 mg) per injection site has been reported. This higher single dose is well tolerated with limited skin reactions, no significant hypotension and facilitates ease of administration with only 5 patients needing two injections per visit. If the maximum volume for injection was kept at 2 mL, a total of 46 patients would have received two injections per visit.