Daratumumab monotherapy in patients with treatment-refractory multiple myeloma (SIRIUS): an open-label, randomised, phase 2 trial

BACKGROUND: New treatment options are needed for patients with multiple myeloma that is refractory to proteasome inhibitors and immunomodulatory drugs. We assessed daratumumab, a novel CD38-targeted monoclonal antibody, in patients with refractory multiple myeloma. METHODS: In this open-label, multicentre, phase 2 trial done in Canada, Spain, and the USA, patients (age ≥18 years) with multiple myeloma who were previously treated with at least three lines of therapy (including proteasome inhibitors and immunomodulatory drugs), or were refractory to both proteasome inhibitors and immunomodulatory drugs, were randomly allocated in a 1:1 ratio to receive intravenous daratumumab 8 mg/kg or 16 mg/kg in part 1 stage 1 of the study, to decide the dose for further assessment in part 2. Patients received 8 mg/kg every 4 weeks, or 16 mg/kg per week for 8 weeks (cycles 1 and 2), then every 2 weeks for 16 weeks (cycles 3-6), and then every 4 weeks thereafter (cycle 7 and higher). The allocation schedule was computer-generated and randomisation, with permuted blocks, was done centrally with an interactive web response system. In part 1 stage 2 and part 2, patients received 16 mg/kg dosed as in part 1 stage 1. The primary endpoint was overall response rate (partial response [PR] + very good PR + complete response [CR] + stringent CR). All patients who received at least one dose of daratumumab were included in the analysis. The trial is registered with ClinicalTrials.gov, number NCT01985126. FINDINGS: The study is ongoing. In part 1 stage 1 of the study, 18 patients were randomly allocated to the 8 mg/kg group and 16 to the 16 mg/kg group. Findings are reported for the 106 patients who received daratumumab 16 mg/kg in parts 1 and 2. Patients received a median of five previous lines of therapy (range 2-14). 85 (80%) patients had previously received autologous stem cell transplantation, 101 (95%) were refractory to the most recent proteasome inhibitors and immunomodulatory drugs used, and 103 (97%) were refractory to the last line of therapy. Overall responses were noted in 31 patients (29.2%, 95% CI 20.8-38.9)-three (2.8%, 0.6-8.0) had a stringent CR, ten (9.4%, 4.6-16.7) had a very good PR, and 18 (17.0%, 10.4-25.5) had a PR. The median time to first response was 1.0 month (range 0.9-5.6). Median duration of response was 7.4 months (95% CI 5.5-not estimable) and progression-free survival was 3.7 months (95% CI 2.8-4.6). The 12-month overall survival was 64.8% (95% CI 51.2-75.5) and, at a subsequent cutoff, median overall survival was 17.5 months (95% CI 13.7-not estimable). Daratumumab was well tolerated; fatigue (42 [40%] patients) and anaemia (35 [33%]) of any grade were the most common adverse events. No drug-related adverse events led to treatment discontinuation. INTERPRETATION: Daratumumab monotherapy showed encouraging efficacy in heavily pretreated and refractory patients with multiple myeloma, with a favourable safety profile in this population of patients. FUNDING: Janssen Research & Development

Daratumumab plus lenalidomide and dexamethasone for untreated myeloma

This is an accepted manuscript of an article published by Massachusetts Medical Society in New England Journal of Medicine on 30/05/2019, available online: https://doi.org/10.1056/NEJMoa1817249 The accepted version of the publication may differ from the final published version.Copyright © 2019 Massachusetts Medical Society. Lenalidomide plus dexamethasone is a standard treatment for patients with newly diagnosed multiple myeloma who are ineligible for autologous stem-cell transplantation. We sought to determine whether the addition of daratumumab would significantly reduce the risk of disease progression or death in this population. METHODS We randomly assigned 737 patients with newly diagnosed multiple myeloma who were ineligible for autologous stem-cell transplantation to receive daratumumab plus lenalidomide and dexamethasone (daratumumab group) or lenalidomide and dexamethasone alone (control group). Treatment was to continue until the occurrence of disease progression or unacceptable side effects. The primary end point was progression-free survival. RESULTS At a median follow-up of 28.0 months, disease progression or death had occurred in 240 patients (97 of 368 patients [26.4%] in the daratumumab group and 143 of 369 patients [38.8%] in the control group). The estimated percentage of patients who were alive without disease progression at 30 months was 70.6% (95% confidence interval [CI], 65.0 to 75.4) in the daratumumab group and 55.6% (95% CI, 49.5 to 61.3) in the control group (hazard ratio for disease progression or death, 0.56; 95% CI, 0.43 to 0.73; P<0.001). The percentage of patients with a complete response or better was 47.6% in the daratumumab group and 24.9% in the control group (P<0.001). A total of 24.2% of the patients in the daratumumab group, as compared with 7.3% of the patients in the control group, had results below the threshold for minimal residual disease (1 tumor cell per 105 white cells) (P<0.001). The most common adverse events of grade 3 or 4 were neutropenia (50.0% in the daratumumab group vs. 35.3% in the control group), anemia (11.8% vs. 19.7%), lymphopenia (15.1% vs. 10.7%), and pneumonia (13.7% vs. 7.9%).Published versio

Evaluation of the QTc prolongation potential of a monoclonal antibody, siltuximab, in patients with monoclonal gammopathy of undetermined significance, smoldering multiple myeloma, or low-volume multiple myeloma

A phase 1 study evaluated the QTc prolongation potential of siltuximab, a chimeric, anti-interleukin-6 mAb, in patients with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), or low-volume MM. Patients with baseline QTcF and QTcB a parts per thousand currency sign 500 ms, QRS < 100 ms, PR < 200 ms and no significant cardiac disease received siltuximab 15 mg/kg q3w, the highest dosage used in clinical studies, for 4 cycles. Twelve-lead ECGs obtained at multiple time points pre- and post-infusion at cycles 1 and 4 were evaluated by central cardiology laboratory. No effect on QTc interval was concluded if the upper limit of least square (LS) mean 90 % CI for QTc change from baseline at each time point was < 20 ms. An effect on QTc prolongation was ruled out, as the upper bound of 90 % CI was < 10 ms at each time point in 27 evaluable patients (13 MGUS, 13 SMM, 1 low-volume MM) with no differences between disease types. Maximum mean QTc increase from baseline occurred 3 h after cycle 1 infusion (QTcF = 3.2 [LS mean 90 % CI -0.01, 6.45] ms; QTcB = 2.7 [-0.69, 6.14] ms). At all other time points, mean QTcF and QTcB increase from baseline was a parts per thousand currency sign1.5 ms and upper bound 90 % CI was a parts per thousand currency sign5.1 ms. Twenty patients had mostly low-grade AEs, including nausea, fatigue (20 % each); thrombocytopenia, headache (each 13 %); dyspnea, leukopenia, neutropenia, paresthesia, abnormal hepatic function, URTI (each 10 %). Three MGUS patients achieved 50 % M-protein reduction. There was no association between siltuximab pharmacokinetics and QTc interval. Siltuximab did not affect the QTc interval. Overall safety was similar to other single-agent siltuximab studies

Daratumumab monotherapy in patients with heavily pretreated relapsed or refractory multiple myeloma: final results from the phase 2 GEN501 and SIRIUS trials

Background: Daratumumab showed encouraging efficacy as monotherapy in patients with heavily pretreated multiple myeloma in the GEN501 and SIRIUS studies. Here we report a pooled, post-hoc final analysis of these two studies. Methods: GEN501 was an open-label, multicentre, phase 1–2, dose escalation and expansion study done in the Netherlands, the USA, Sweden, and Denmark. Eligible patients had multiple myeloma and had relapsed or were refractory to 2 or more previous lines of treatment that included a proteasome inhibitor or an immunomodulatory drug. SIRIUS was an open-label, multicentre, phase 2 study done in Canada, Spain, and the USA, in which eligible patients with multiple myeloma had received 3 or more previous lines of therapy, including a proteasome inhibitor or an immunomodulatory drug, or were double refractory. In both studies, eligible patients were aged 18 years or older and had an Eastern Cooperative Oncology Group performance status of 2 or less. In part 2 of GEN501, patients were given intravenous daratumumab 16 mg/kg once per week for 8 weeks, twice per month for 8 doses, and then once per month until disease progression. In part 2 of SIRIUS, patients received intravenous daratumumab 16 mg/kg once per week for 8 weeks, twice per month for 16 weeks, and once per month until disease progression. The primary endpoints (safety in GEN501 and overall response rate in SIRIUS) have previously been reported. These trials are registered on ClinicalTrials.gov, NCT00574288 (GEN501) and NCT01985126 (SIRIUS). Findings: Patients were enrolled in GEN501 from March 27, 2008, until May 30, 2014, and in SIRIUS from Sept 30, 2013, until May 5, 2014. The combined analysis included 148 patients who received daratumumab 16 mg/kg (42 patients in GEN501 part 2; 106 patients in SIRIUS), with a median follow-up of 36·6 months (IQR 34·5–38·2). Patients had received a median of 5 previous lines of therapy (IQR 4–7), and 128 (87%) of 148 patients were double refractory. The overall response rate was 30·4% (95% CI 23·1–38·5), including 20 (14%) of 148 patients with very good partial response or better (8·5–20·1) and seven (5%) patients reporting complete response or better (1·9–9·5). Among 45 responders, the median duration of response was 8·0 months (95% CI 6·5–14·7). Median overall survival was 20·5 months (95% CI 16·6–28·1), with a 3-year overall survival rate of 36·5% (28·4–44·6). The most common grade 3–4 treatment-emergent adverse events (TEAEs) were anaemia (grade 3, 26 [18%] of 148 patients; no grade 4 events) and thrombocytopenia (grade 3, 13 [9%] of 148 patients; grade 4, 8 [5%] of 148 patients). Serious drug-related TEAEs occurred in 13 (9%) of 148 patients. There were no treatment-related deaths. Interpretation: In this analysis, daratumumab 16 mg/kg monotherapy showed durable responses and there were no new safety concerns with longer follow-up. Funding: Janssen Research & Development

Clinical efficacy of daratumumab monotherapy in patients with heavily pretreated relapsed or refractory multiple myeloma

The efficacy and favorable safety profile of daratumumab monotherapy in multiple myeloma (MM) was previously reported. Here, we present an updated pooled analysis of 148 patients treated with daratumumab 16 mg/kg. Data were combined from part 2 of a first-in-human phase 1/2 study of patients who relapsed after or were refractory to ≥2 prior therapies and a phase 2 study of patients previously treated with ≥3 prior lines of therapy (including a proteasome inhibitor [PI] and an immunomodulatory drug [IMiD]) or were double refractory. Among the pooled population, patients received a median of 5 prior lines of therapy (range, 2 to 14 prior lines of therapy), and 86.5% were double refractory to a PI and an IMiD. Overall response rate was 31.1%, including 13 very good partial responses, 4 complete responses, and 3 stringent complete responses. The median duration of response was 7.6 months (95% confidence interval [CI], 5.6 to not evaluable [NE]). The median progression-free survival (PFS) and overall survival (OS) were 4.0 months (95% CI, 2.8-5.6 months) and 20.1 months (95% CI, 16.6 months to NE), respectively. When stratified by responders vs stable disease/minimal response vs progressive disease/NE, median PFS was 15.0 months (95% CI, 7.4 months to NE) vs 3.0 months (95% CI, 2.8-3.7 months) vs 0.9 months (95% CI, 0.9-1.0 months), respectively, and median OS was NE (95% CI, NE to NE) vs 18.5 months (95% CI, 15.1-22.4 months) vs 3.7 months (95% CI, 1.7-7.6 months), respectively. No new safety signals were identified. In this pooled data set, daratumumab 16 mg/kg monotherapy demonstrated rapid, deep, and durable responses, with a clinical benefit that extended to patients with stable disease or better

Targeting CD38 with daratumumab monotherapy in multiple myeloma

Background: Multiple myeloma cells uniformly overexpress CD38. We studied daratumumab, a CD38-targeting, human IgG1κ monoclonal antibody, in a phase 1-2 trial involving patients with relapsed myeloma or relapsed myeloma that was refractory to two or more prior lines of therapy. Methods: In part 1, the dose-escalation phase, we administered daratumumab at doses of 0.005 to 24 mg per kilogram of body weight. In part 2, the dose-expansion phase, 30 patients received 8 mg per kilogram of daratumumab and 42 received 16 mg per kilogram, administered once weekly (8 doses), twice monthly (8 doses), and monthly for up to 24 months. End points included safety, efficacy, and pharmacokinetics. Results: No maximum tolerated dose was identified in part 1. In part 2, the median time since diagnosis was 5.7 years. Patients had received a median of four prior treatments; 79% of the patients had disease that was refractory to the last therapy received (64% had disease refractory to proteasome inhibitors and immunomodulatory drugs and 64% had disease refractory to bortezomib and lenalidomide), and 76% had received autologous stem-cell transplants. Infusion-related reactions in part 2 were mild (71% of patients had an event of any grade, and 1% had an event of grade 3), with no dose-dependent adverse events. The most common adverse events of grade 3 or 4 (in ≥5% of patients) were pneumonia and thrombocytopenia. The overall response rate was 36% in the cohort that received 16 mg per kilogram (15 patients had a partial response or better, including 2 with a complete response and 2 with a very good partial response) and 10% in the cohort that received 8 mg per kilogram (3 had a partial response). In the cohort that received 16 mg per kilogram, the median progression-free survival was 5.6 months (95% confidence interval [CI], 4.2 to 8.1), and 65% (95% CI, 28 to 86) of the patients who had a response did not have progression at 12 months. Conclusions: Daratumumab monotherapy had a favorable safety profile and encouraging efficacy in patients with heavily pretreated and refractory myeloma