At 5 years of follow-up of the VISTA trial, the combination of bortezomib plus melphalan and prednisone (VMP) demonstrated a survival advantage over MP alone as up-front treatment of patients with multiple myeloma who were not transplant candidates. At a median followup of 60.1 months, the absolute difference in overall survival (OS) between the treatment arms was 13 months, according to final results presented at the 53rd Annual Meeting of the American Society of Hematology. Patients assigned to the MP arm who took bortezomib at disease progression failed to achieve the survival advantage of those who received bortezomib as part of up-front treatment.
“The 5-year results of VISTA confirm the significant survival benefit of VMP versus MP…. These data demonstrate that it is important to provide the best induction therapy—VMP— up front,” stated Jesús San Miguel, MD, Universitario de Salamanca, Salamanca, Spain.
The study population included 682 patients, with a median age of 71 years; 30% were aged 75 and older, and one-third had advanced disease. Less than 5% of patients in each arm were lost to follow-up.
Median OS was 56 months with VMP versus 43 months with MP (P = .0004). The benefit of up-front VMP was maintained across all prespecified subgroups, including patients with high-risk cytogenetics. Time to next treatment was significantly longer in VMP-treated versus MP-treated patients (median of 27 months vs 19.2 months, respectively; P <.0001), and treatment-free interval was also longer (16.6 months vs 8.3 months, respectively; P <.0001).
A similar percentage of patients in each group received subsequent therapies at relapse, with the exception of bortezomib: 22% in the VMP group versus 43% of patients in the MP group were treated with bortezomib at relapse. Among patients who required subsequent anticancer therapies, OS was significantly longer in patients treated with VMP up front: median 55.7 months versus 46.4 months, respectively (P = .0162).
Regarding the safety of VMP, San Miguel said, “We saw no emerging safety signal for an increase in secondary primary malignancies [SPMs]. I think these data on SPMs are solid, with the rate as expected in the general population or even lower. VMP is completely safe.”
Hematologic SPMs were reported in 3 patients (1%) in each group over the 5-year follow-up; nonhematologic SPMs were found in 16 patients in the VMP group and 10 in the MP group. The expected rate of SPMs in the general population is 1.9 per 100 patient-years; the rate in the VMP arm was lower than expected at 1.6 per 100 patient-years, and the rate in the MP arm was 1.3.