HOVON-65/GMMG-HD4 Randomized Phase III Trial Comparing Bortezomib, Doxorubicin, Dexamethasone (PAD) Vs VAD Followed by High-Dose Melphalan (HDM) and Maintenance with Bortezomib or Thalidomide In Patients with Newly Diagnosed Multiple Myeloma (MM)

This independent trial was designed to evaluate the efficacy of bortezomib (B) during induction and maintenance on progression-free survival (PFS) in patients with newly diagnosed symptomatic MM, who were candidates for high-dose therapy. Patients were randomly assigned to 3 cycles of standard VAD (arm A) or PAD (Arm B); PAD was dosed as B 1.3 mg/m2, days 1,4,8,11, doxorubicin 9 mg/m2, days 1–4, dexamethasone 40 mg, days 1–4, 9–12, 17–20). Patients received one (HOVON) or two (GMMG) high-dose melphalan (HDM) 200 mg/m2 with ASCT. Maintenance consisted of thalidomide (T) 50 mg daily (arm A) or B 1.3 mg/m2, 2-weekly (arm B) for 2 years. Primary endpoint was PFS, other endpoints were complete response (CR) (EBMT), immunofixation positive CR (nCR), VGPR pre-and post HDM and survival (OS). The protocol specified analysis was intention-to-treat and censored for patients who received allo-SCT after HDM1 (n=46). We report the analysis of the first 626 randomized patients. The final analysis of all patients will be presented at the meeting.

13 patients were excluded (7 not eligible, 6 not evaluable). The two arms (A:n=305;B:n=308) were well balanced for age, Salmon/Durie stage II/III, renal failure (11%), and serum B2M. Medium follow-up is 40 months. 89% of patients completed induction and HDM1. In GMMG after HDM1 80% of patients received 2nd HDM. Full dose B could be administered in 82% of patients. Polyneuropathy (PNP) WHO gr 3+4 occurred in 7% (arm A) and 16% (arm B). 204 (67%, arm A) and 174 (57%, arm B) patients started maintenance. 64% of patients tolerated full dose B and 27% reduced dose. 47% of patients on B maintenance went off protocol because of toxicity (9%), progression (29%) or other (9%). In contrast 64 % on T maintenance went off protocol because of toxicity (31%), progression (31%) or other (2%).

nCR/CR rates were 7/9% (arm A) vs 9/21% (arm B) at 3 months after HDM-1 and 12/26% (arm A) vs 12/38% (arm B) on protocol. ≥VGPR in arm-A vs arm-B were 40% vs 60% after HDM-1 and 61% vs 75% on protocol. PFS was superior in arm B (HR 0.81, p=0.047; adjusted for ISS: HR 0.81, p=0.056). PFS at 36 months was 42% (arm A) vs 46% (arm B). Multivariate Cox regression showed treatment arm (p=0.037), IgA (p=0.007), ISS stage (p=0.007), WHO Performance Status (p<0.0001), del13/13q- (p=0.015) and study group (2nd HDM) (p=0.015) as significant PFS variables. Patients treated with bortezomib had a better OS (HR 0.74, p=0.048), with study arm, WHO, IgA, ISS stage and del13/13q- as significant variables. Subgroup analysis of response at 12 months showed no impact on PFS and an impact of VGPR/nCR/CR on OS only in arm A. Adverse cytogenetic markers (p<0.05) in the combined group were 13q14, 17p-, t(4;14) for PFS and OS. Detailed FISH data are reported separately. The response and survival data of the subgroup analysis are given below. We conclude that B achieves high nCR/CR during induction, that B maintenance is well tolerated and is associated with additional responses. Bortezomib achieves superior PFS and results in an improvement of survival.

This trial (EudraCT no. 2004-000944-26) was supported by the Dutch Cancer Foundation, the German Federal Ministry of Education and Research and a grant from Janssen-Cilag.

Sonneveld:celgene: Membership on an entity's Board of Directors or advisory committees; janssen-Cilag: Membership on an entity's Board of Directors or advisory committees; millennium: Membership on an entity's Board of Directors or advisory committees. Off Label Use: bortezomib, induction treatment prior to high dose therapy. Schmidt-Wolf:celgene: Membership on an entity's Board of Directors or advisory committees; janssen-Cilag: Research Funding. van de Velde:Johnson & Johnson: Employment, Equity Ownership. Delforge:celgene: Membership on an entity's Board of Directors or advisory committees; janssen-cilag: Membership on an entity's Board of Directors or advisory committees. Weisel:orthobiotech: Consultancy, Membership on an entity's Board of Directors or advisory committees; celgene: Membership on an entity's Board of Directors or advisory committees. Scheid:orthobiotech: Honoraria. Goldschmidt:celgene: Honoraria, Research Funding; amgen: Honoraria, Research Funding; novartis: Honoraria, Research Funding; orthobiotech: Honoraria, Research Funding; roche: Honoraria, Research Funding.