Onyx Pharmaceuticals, Inc., an Amgen subsidiary.

Background Selinexor with dexamethasone has demonstrated activity in patients with heavily pretreated multiple myeloma (MM). In a phase 1b/2 study, the combination of oral selinexor with the proteasome inhibitor (PI) bortezomib, and dexamethasone (SVd) induced high response rates with low rates of peripheral neuropathy, the main dose-limiting toxicity of bortezomib. The aim of this trial was to evaluate the clinical benefit of weekly SVd versus standard bortezomib and dexamethasone (Vd) in patients with previously treated MM.Methods This phase 3, randomised, open label trial was conducted at 123 sites in 21 countries.Patients who were previously treated with one to three lines of therapy, including PIs were randomised (1:1) to selinexor (100 mg once-weekly) plus bortezomib (1•3 mg/m 2 once-weekly) and dexamethasone (20 mg twice-weekly) [SVd] or bortezomib (1•3 mg/m 2 twice-weekly) and dexamethasone (20 mg 4 times per week) [Vd]. Randomisation was done using interactive response technology and stratified by previous PI therapy, lines of treatment, and MM stage. The primary endpoint was progression-free survival (PFS) in the intention-to-treat population.Patients who received at least one dose of study treatment were included in the safety population. This trial is registered at ClinicalTrials.gov, NCT03110562.

Key Points KRd has a favorable benefit-risk profile compared with Rd, regardless of baseline cytogenetic risk status, in patients with relapsed MM. KRd improves but does not abrogate the poor prognosis associated with high-risk cytogenetics in patients with relapsed MM.

We compared the safety and efficacy of siltuximab (S), an anti-interleukin-6 chimeric monoclonal antibody, plus bortezomib (B) with placebo (plc)+B in patients with relapsed/refractory multiple myeloma in a randomized phase II study. Siltuximab was given by 6 mg/kg IV every 2 weeks. On progression, B was discontinued and high-dose dexamethasone could be added to S/plc. Response and progression-free survival (PFS) were analyzed pre-dexamethasone by EBMT criteria. For the 281 randomized patients, median PFS for S+B and plc+B was 8.0 and 7.6 months (HR 0.869, p=0.345), overall response rate was 55% vs. 47% (p=0.213), complete response rate was 11% vs. 7%, and median overall survival (OS) was 30.8 vs. 36.8 months (HR 1.353, p=0.103). Sustained suppression of C-reactive protein, a marker reflective of inhibition of interleukin-6 activity, was seen with S+B. Siltuximab did not affect B pharmacokinetics. S/plc discontinuation (75% vs. 66%), grade ≥3 neutropenia (49% vs. 29%), thrombocytopenia (48% vs. 34%), and all-grade infections (62% vs. 49%) occurred more frequently with S+B. The addition of siltuximab to bortezomib did not appear to improve PFS or OS despite a numerical increase in response rate in patients with relapsed or refractory multiple myeloma.