The use of triple agent induction therapy before first line high-dose therapy (HDT) and autologous stem cell transplant (ASCT) in multiple myeloma is now considered standard of care. Cross-study comparisons show that the combinations of proteasome inhibitors (PIs) and immunomodulatory drugs (IMIDs) have the highest response rates (Malankody Nat Rev Clin Onc 2015).
In recent years there has been a shift in choice of induction therapy from the VCD to the RVD regimen in our region. We have evaluated how this shift has affected depth of response 3 months after ASCT in all patients receiving first line HDT with ASCT in our region from January 1st, 2015, and how frequently our patients needed to change induction regimen, based on choice of first line therapy.
All patients receiving first line HDT with ASCT for multiple myeloma in our institution in the period from January 1st, 2015 to October 26th, 2019 were evaluated for the final analysis of response 3 months post-ASCT. The patients received 3-5 cycles of induction therapy before leukapheresis, HDT (melphalan 200 mg/m2) and ASCT. All patients received a follow-up consultation in our institution 3 months post-ASCT, where response was evaluated and recorded according to the IMWG 2016 response criteria.Age, sex, date of ASCT, the presence of high-risk cytogenetics, ISS stage at diagnosis, choice of induction regimen and response 3 months post-ASCT was recorded by the primary investigator (Table 1).
48.3% (125 patients) received VCD as first-line induction therapy, while 37.5% (97 patients) received RVD. 12.0% (15 patients) in the VCD group changed induction therapy vs 5.2% (5 patients) in the RVD group. In the RVD group 87.5% (77 patients) achieved ≥VGPR vs 84.5% (93 patients) in the VCD group. In addition, 11.3% in the RVD group (8 patients) achieved PR, while 3.4% (3 patients) had disease progression (PD) 3 months after ASCT. In the VCD group, 13.6% (15 patients) achieved PR, while 1.8% (2 patients) had PD 3 months after ASCT (Table 2, Figure 1). 26% (32 patients) starting VCD induction therapy and 16% (16 patients) starting RVD achieved a response rate <VGPR, or needed to switch induction regimen. We define this as a poor outcome (figure 2).
RVD induction therapy before HDT with ASCT trended toward higher rates of at least VGPR compared to VCD induction (87.5% s 84.5%). The choice of RVD as first line induction therapy necessitated fewer changes of induction regimen due to insufficient response or unacceptable toxicities compared to VCD induction (5.2% vs 12.0%). Fewer patients receiving RVD induction achieved a “poor outcome”: Response <VGPR or need to change induction regimen. These results should be confirmed in larger patient materials, and in prospective studies. Updated data with approximately 30 additional patients, mainly receiving RVD induction, will be presented at the EHA annual meeting if our abstract is selected for presentation.