First Analysis of HOVON-65/GMMG-HD4 Randomized Phase III Trial Comparing Bortezomib, Adriamycine, Dexamethasone (PAD) Vs VAD as Induction Treatment Prior to High Dose Melphalan (HDM) in Patients with Newly Diagnosed Multiple Myeloma (MM)

The randomized, open-label, phase III trial HOVON-65/GMMG-HD4 was designed to evaluate the efficacy of bortezomib prior to HDM for response and progression-free survival (PFS) in patients with newly diagnosed MM. The trial was performed in 75 referral centers in the Netherlands and Belgium (HOVON group) and Germany (GMMG group). Patients with Salmon & Durie (SD) stage II or III, age 18–65 years inclusive, were randomly assigned to 3 cycles of VAD (vincristine 0.4 mg, adriamycine 9 mg/m2 days 1–4, dexamethasone 40 mg days 1–4, 9–12, and 17–20) or PAD (bortezomib 1.3 mg/m2 days 1,4,8,11, adriamycine 9 mg/m2 days 1–4, dexamethasone 40 mg days 1–4, 9–12, and 17–20). No thrombosis prophylaxis was given. Stem cells were mobilized using the CAD regimen, including cyclophosphamide 1000 mg/m2 iv day 1, and G-CSF. After induction therapy, all patients were to receive 1 or 2 cycles of high-dose melphalan (HDM) 200 mg/m2 with autologous stem cell rescue followed by maintenance with thalidomide 50 mg daily (VAD arm) or bortezomib, 1.3 mg/m2 once every 2 weeks (PAD arm) for 2 years. Between May 4, 2005 and May 16, 2008, 833 patients were randomized. After the trial was closed, we here report the planned interim analysis data on response after induction and HDM-1 of the initial 150 (75 per arm) randomized patients. The data of the initial 300 registered patients (150 per arm) will be available by November 1, 2008 and presented. The 2 randomization arms were equal for SD stage of disease, ISS stage, and distribution of chromosomal abnormalities. 134 patients (89%) completed PAD/VAD and 130 patients (87%) completed HDM-1, with no difference between the treatment arms. Full dose bortezomib could be administered in 95 % (PAD1), 79 % (PAD2) and 85 % (PAD3) of patients. Successful stem cell apheresis was achieved in all 132 patients who received CAD. Adverse events CTC grade 2–4 during PAD vs VAD included neurologic or polyneuropathy (PNP) 38% vs 21 %, constitutional symptoms 30 % vs 24 %. PNP of CTC grade 1–4 was more frequent in the PAD arm (p=0.01), while DVT/pulmonary embolism was diagnosed in 10 % during VAD and 6 % during PAD. Responses were assessed according to EBMT criteria including VGPR after PAD/VAD, after HDM-1 and best response on protocol treatment. Complete Response (CR), Very Good Partial Response (VGPR) and Partial Response (PR) in both arms were compared by logistic regression (table 1)

The (preliminary) overall complete response rate including maintenance was 27 % (PAD arm) and 5% (VAD arm) (p=0.001). Deletion of chromosome 13q did not have a significant impact on response. We conclude that PAD induces significantly more PR+VGPR+CR as compared with VAD, and that this effect is sustained after HDM-1. This trial was supported by the Dutch Cancer Foundation (EudraCT nr 2004-000944-26), the German Federal Ministry of Education and Research and a grant from Johnson and Johnson