Background

The MM5 phase III trial of the German-Speaking Myeloma Multicenter Group (GMMG) was designed to address two independent primary objectives: 1.) demonstration of non-inferiority of VCD (bortezomib, cyclophosphamide, dexamethasone) induction compared to PAd (bortezomib, adriamycin, dexamethasone) induction therapy with respect to response rate (very good partial response or better). 2.) determination of the best of four treatment strategies with respect to progression-free survival (PFS). The four treatment strategies were defined by PAd vs. VCD induction treatment, high dose melphalan (HDM) followed by autologous stem cell transplantation (ASCT) as well as consolidation and maintenance treatment with lenalidomide for 2 years vs. lenalidomide until complete response (CR).

Methods

504 patients were included in the trial between July 2010 and October 2012. A non-inferiority analysis of VCD compared to PAd with respect to response rates after induction treatment with a non-inferiority margin of 10% for the difference in response rates (VGPR and better; first primary endpoint) and a safety analysis were performed. During the induction phase the patients were treated with 3 cycles of PAd or VCD. PAd was dosed as bortezomib 1.3 mg/m2, days 1, 4, 8, 11, doxorubicin 9 mg/m2, days 1-4, dexamethasone 20 mg, days 1-4, 9-12, 17-20 (repeated every 28 days). VCD consisted of bortezomib 1.3 mg/m2, days 1, 4, 8, 11, cyclophosphamide 900 mg/m2 day 1, dexamethasone 40 mg, days 1-2, 4-5, 8-9, 11-12 (repeated every 21 days). The route of administration for bortezomib was changed from intravenously to subcutaneously in all study arms by a protocol amendment in February 2012 after inclusion of 314 patients. The non-inferiority analysis was based on intention-to-treat (ITT) population (502 evaluable patients) and per-protocol (PP) population (473 evaluable patients). Responses were assessed according to the response criteria of the International Myeloma Working Group (IMWG).

Results

In the ITT population, patients treated with PAd or VCD were equally distributed for ISS and Durie-Salmon disease stage, LDH, kidney function and the cytogenetic abnormalities translocation t(4;14), deletion 17p13 and gain 1q21. In the PAd group, the median age of the patients was higher (59.4 vs. 58.7, p=0.04). 229 of 251 patients (91.2%) in the PAd group and 241 of 251 patients (96.0%) in the VCD group completed induction treatment. Observed response rates (PAd vs. VCD) were 4.4% vs 8.4% for complete response, 34.3% vs. 37.0% for ≥ very good partial response and 72.1% vs. 78.1% for ≥ partial response. Non-inferiority of VCD compared to PAd was shown (two-sided p=0.0026). Similar results were obtained in the PP analysis.

The proportion of patients with any adverse event (AEs) was comparable in PAd vs. VCD (61.3% vs. 64.0%, p=0.58), but more serious adverse events (SAEs) were observed during PAd induction (32.7% vs. 24.0%, p=0.037). VCD led to a significantly higher proportion of leukopenia and neutropenia CTCAE grade 3 and 4 (PAd: 11.3% vs. VCD: 35.2%; p<0.001). There was no significant difference in the number of infections (≥ CTCAE grade 2) during PAd induction compared to VCD induction (24.6% vs. 22.4%; p=0.60). Interestingly, compared to the infection rate (≥ CTCAE grade 2) of 49% during PAD (dexamethasone 40 mg days 1-4, 9-12, 17-20) in the HOVON65/GMMG-HD4-trial, a reduction in MM5 during induction was observed. In the PAd arm more deaths were observed compared to the VCD arm (6 vs. 1).

Conclusion

PAd and VCD are well tolerated with more than 90% of the patients receiving all three planned induction cycles. Non-inferiority of VCD compared to PAd was shown in ITT and PP analysis. In conclusion, VCD was found to be a valid alternative to PAd with comparable efficacy and a favourable toxicity profile.

Disclosures:

Goldschmidt:Celgene: Consultancy, Honoraria, Research Funding; Chugai: Research Funding; Janssen Cilag: Consultancy, Honoraria, Research Funding. Duerig:Janssen Cilag: Honoraria; Celgene: Honoraria. Schmidt-Wolf:Janssen: Honoraria; Novartis: Honoraria. Weisel:Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding. Scheid:Janssen Cilag: Honoraria; Celgene: Honoraria; Novartis: Honoraria. Salwender:Janssen Cilag: Honoraria; Celgene: Honoraria.

Author notes

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Asterisk with author names denotes non-ASH members.