Tolerance, Kinetics, and Depth of Response for Subcutaneous Versus Intravenous Administration of Bortezomib Combination in Chinese Patients With Newly Diagnosed Multiple Myeloma.

BACKGROUND: Peripheral neuropathy (PN) is an important toxicity that limits the use of bortezomib (Btz). Attempts to reduce PN have included its subcutaneous (SC) administration.

PATIENTS AND METHODS: We retrospectively analyzed 307 patients with newly diagnosed multiple myeloma from a single Chinese center, receiving Btz-based regimens administered either via SC injection (SC group, n = 167) or intravenous (IV) infusion (IV group, n = 140). The efficacy and safety of Btz administration via SC and IV were then compared.

RESULTS: Most baseline characteristics were similar between these 2 groups. A lower frequency of adverse events, especially grade ≥ 3 PN (P = .002), was observed in the SC group compared with the IV group. The estimated median Btz dosage when PN developed was higher (20.8 mg/m2 vs. 15.6 mg/m2 ), and fewer patients reduced or discontinued Btz owing to adverse events in the SC group compared with the IV group. The overall response rate (≥ partial response [PR]) was comparable (94.8% vs. 96.2%). However, patients in the IV group required fewer cycles to achieve PR, whereas a larger proportion of patients in the IV group achieved ≥ very good PR. After a median follow-up of 23 months (range, 1-84 months), no significant difference in median progression-free survival (not arrived vs. 33.0 ± 2.735 months) and overall survival (not arrived vs. 56.0 months) was noted.

CONCLUSION: SC Btz is associated with better tolerance; however, IV administration achieves a faster and deeper response in Chinese patients with newly-diagnosed multiple myeloma.