Dose intensity and treatment duration of bortezomib in transplant-ineligible newly diagnosed multiple myeloma

Real-world Outcomes With Cumulative Bortezomib Dose and Efficacy in the Treatment of Transplant-ineligible Multiple Myeloma With Cyclophosphamide, Bortezomib, and Dexamethasone

BACKGROUND

Higher cumulative dose of bortezomib, a key component of Multiple Myeloma (MM) treatment regimens, has been shown to improve outcomes in MM patients, but must be balanced with toxicities including peripheral neuropathy. In this study, we studied the effect of cumulative bortezomib dose on survival, depth of response, and discontinuation rate in transplant ineligible MM patients.

PATIENTS AND METHODS

Data from 70 patients treated with Cyclophsophamide, Bortezomib, and Dexamethasone (CyBorD) in a single Canadian center were grouped according to above vs below median cumulative bortezomib dose and analyzed for progression-free survival (PFS), overall survival (OS), depth of response, and discontinuation rate.

RESULTS

There was a trend for lower discontinuation rate (45.7% vs. 68.6%, P = .052) and significantly lower rate of neuropathy-related discontinuation (5.7% vs. 22.9%, P = .035) in patients who received higher than 43.1 mg/m² of bortezomib. The higher-dose group showed a trend for higher rate of complete response (14.3% vs. 5.7%, P = .225) and significantly higher rate of very good partial response or better (77.1% vs. 51.4%, P = .024). There was significantly longer PFS (24.3 vs. 9.1 months, P = .012) and a trend for longer OS (22.4 vs. 61.3 months, P = .061) in the higher-dose group. In landmark analysis after 180 days, PFS (23.5 vs. 24.3 months, P = .941) and OS were similar in both groups.

CONCLUSION

Higher cumulative bortezomib dose showed a lower rate of discontinuation, longer survival, and deeper response. Determining risk of treatment intolerance remains important for treatment.

Bortezomib advanced mechanisms of action in multiple myeloma, solid and liquid tumors along with its novel therapeutic applications

Bortezomib (BTZ) is a first-in-class reversible and selective proteasome inhibitor. It inhibits the ubiquitin proteasome pathway that leads to the degradation of many intracellular proteins. Initially, BTZ was FDA approved for the treatment of refractory or relapsed multiple myeloma (MM) in 2003. Later, its usage was approved for patients with previously untreated MM. In 2006, BTZ was approved for the treatment of relapsed or refractory Mantle Cell Lymphoma (MCL) and, in 2014, for previously untreated MCL. BTZ has been extensively studied either alone or in combination with other drugs for the treatment of different liquid tumors especially in MM. However, limited data evaluated the efficacy and safety of using BTZ in patients with solid tumors. In this review, we will discuss the advanced and novel mechanisms of action of BTZ documented in MM, solid tumors and liquid tumors. Moreover, we will shed the light on the newly discovered pharmacological effects of BTZ in other prevalent diseases.