Consolidation with Bortezomib, Thalidomide and Dexamethasone After High Dose Therapy Is Feasible, Safe and Effective In De Novo Multiple Myeloma Patients Who Already Received New Drugs Containing-Induction Regimen
Authors: Roussel Murielle , Dörr Gaëlle , Vaillant Willy , Huynh Anne , Attal Michel 
Published: October 2019

Abstract
Abstract 3041
High dose therapy (HDT) with autologous stem cell transplantation (ASCT) is a standard treatment option for frontline myeloma patients (pts). However, after a single or a double transplantation, almost all pts ultimately relapse. Thus, new strategies are required to control the residual disease after HDT. Consolidation therapy, given early after HDT, could enhance the depth of response and further improve progression free survival (PFS) and overall survival (OS). The IFM (Intergroupe Francophone du Myélome) previously reported that either Thalidomide or Lenalidomide, administered after HDT, was able to reduce this residual disease (IFM 99-02 and 2005-02 trials, Attal M et al. Blood 2006 and ASCO 2010). Ladetto M et al. (JCO 2010) also reported a major shrinking of residual tumor cell burden in myeloma pts undergoing early consolidation with Bortezomib, Thalidomide and Dexamethasone (VTD) after ASCT. None of these pts had previously received treatment with Thalidomide and/or Bortezomib during induction. The aim of this study was to evaluate the feasibility, safety and efficacy of early consolidation therapy in pts who had received new drugs containing-induction therapies before ASCT.

Patients and Methods:
In this prospective monocenter study,patients were eligible if they had the following: 1) at least partial response (PR) after HD melphalan (HDM), 2) no grade ≥ 2 peripheral neuropathy (PNY). The consolidation therapy with vTD had to be started within 3 months from ASCT for a total of 2 cycles. Each 4-week cycle consisted of: a) Bortezomib: 1mg/m2 as an IV injection twice weekly (on days 1, 4, 8, 11); b) oral Thalidomide: 100 mg/day; c) oral Dexamethasone 40 mg/day once a week (on days 1, 8, 15 and 22). Pts did not receive maintenance therapy after vTD consolidation. A systematic prophylactic anticoagulation therapy was given either by aspirin or low molecular weight heparin. Pts also received systematic anti herpes zoster prophylaxis with valacyclovir. Toxicities were graded according to the CTAECv4 at each cycle. Response was assessed according to modified European group for Blood and Marrow Transplantion criteria including very good partial response (VGPR), 1 month after the last cycle of vTD. As no immunophenotypic analysis was available routinely in our institute, we did not evaluate stingent complete response.

Results:
From August 2008 to May 2010, 90 newly diagnosed multiple myeloma pts under 65 received HDM followed by ASCT in the Toulouse's hospital bone marrow transplant unit, FRANCE. Forty-six pts were eligible for this study and started on consolidation. Two pts are ongoing their treatment and 41 received the whole planned treatment. Two pts withdrawn thalidomide and 1 pt did not receive the second cycle of consolidation because of toxicities. Forty-four pts were excluded mainly because of PN (27%). Initial characteristics were: age=58 years (range,44-65); ISS: 1= 50%, 2= 23%, 3=18%, NA= 9%; DS stage: I=4,5%, II=4,5%, III=91%; median beta-2microglobulin=2,9 mg/l (1,3-11,3); FISH analysis: t(4-14) and/or del 17p= 4/29 evaluable pts. The induction regimen was: Bortezomib/Dexamethasone (82%), vTD (11%), or another regimen (7%).
Before consolidation therapy, response rates were: PR=16%, VGPR=48%, near complete response (nCR)=14% and CR=23%. In an Intend to treat basis, 17 pts (39%) improved their responses after consolidation with vTD: 3 pts (7%) from PR to VGPR, 8 pts (18%) from VGPR to nCR, and 6 pts (14%) from VGPR to CR. Response improvement was also reported in the 5 pts who already received induction therapy with vTD; three pts (60%) improved their response: 1 pt from PR to VGPR and 2 pts from VGPR to nCR. As immunophenotypic analysis was not avalaible, response improvement might be underestimate for CR pts. Overall, consolidation therapy with 2 cycles of vTD was efficient; 16 pts (36%) acheived CR, 30 pts (68%) CR+nCR and 40 pts (91%) VGPR or better.
Considering the safety profile, there was no toxic death or grade 3/4 hematological toxicity. Non-hematological toxicities reported were: fatigue=18%, PNY (all grades)= 9%, pneumonia=7%, vertigo= 7%, constipation= 6%, and deep-vein thrombosis= 4,5%.

Conclusions:
Early consolidation with vTD in pts who already received Thalidomide and/or Bortezomib as induction therapy is feasible, safe and effective. Response rates improved in almost 40% of pts.

Disclosures:
Roussel: Janssen: Consultancy, Research Funding, orator; celgene: Consultancy, Orator, Research Funding. Off Label Use: bortezomib and thalidomide as consolidation therapy after High Dose Melphalan. Attal:celgene: Consultancy, Research Funding; janssen: Consultancy, Research Funding.