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Aim: A population pharmacokinetic (PPK) model was developed to characterize pharmacokinetics (PK) of subcutaneous or intravenous daratumumab administration in a new indication (i.e., combination with pomalidomide and dexamethasone [D‐Pd] in patients with relapsed or refractory multiple myeloma [RRMM]). Analyses were conducted to explore exposure–response (E‐R) relationships for efficacy and select treatment‐emergent adverse events (TEAEs). Methods: The PPK analysis included pooled data from the D‐Pd cohorts of the phase 3 APOLLO and phase 1b EQUULEUS studies. Covariates were evaluated in the PPK model. Model‐predicted exposures to daratumumab were compared between covariate subgroups of interest and used to investigate relationships between daratumumab exposure and efficacy and safety in APOLLO. Results: The PPK analysis included 1146 daratumumab PK samples from 239 patients (APOLLO, n = 140; EQUULEUS, n = 99). Observed concentration–time data of daratumumab were well described by a two‐compartment PPK model with first‐order absorption and parallel linear and nonlinear elimination pathways. Treatment with D‐Pd provided similar daratumumab PK characteristics versus historical daratumumab monotherapy. The E‐R dataset contained data from 290 APOLLO patients (D‐Pd, n = 140; Pd, n = 150). The PK–efficacy relationship of daratumumab supported improved progression‐free survival for patients in the D‐Pd group vs. the Pd group. Additionally, TEAEs did not increase with increasing PK exposure in the D‐Pd group. Conclusions: The PPK and E‐R analyses support the daratumumab subcutaneous 1800 mg dosing regimen in combination with Pd for treatment of patients with RRMM. No dose adjustment is recommended in this indication for any of the investigated factors, none of which had clinically relevant effects on daratumumab PK. [ABSTRACT FROM AUTHOR]

Background: In a phase 1b study, intravenous daratumumab plus pomalidomide and dexamethasone induced a very good partial response or better rate of 42% and was well tolerated in patients with heavily pretreated multiple myeloma. We aimed to evaluate whether daratumumab plus pomalidomide and dexamethasone would improve progression-free survival versus pomalidomide and dexamethasone alone in patients with previously treated multiple myeloma.Methods: In this ongoing, open-label, randomised, phase 3 trial (APOLLO) done at 48 academic centres and hospitals across 12 European countries, eligible patients were aged 18 years or older, had relapsed or refractory multiple myeloma with measurable disease, had an Eastern Cooperative Oncology Group performance status of 0-2, had at least one previous line of therapy, including lenalidomide and a proteasome inhibitor, had a partial response or better to one or more previous lines of antimyeloma therapy, and were refractory to lenalidomide if only one previous line of therapy was received. Patients were randomly assigned (1:1) by an interactive web-response system in a random block size of two or four to receive pomalidomide and dexamethasone alone or daratumumab plus pomalidomide and dexamethasone. Randomisation was stratified by number of previous lines of therapy and International Staging System disease stage. All patients received oral pomalidomide (4 mg, once daily on days 1-21) and oral dexamethasone (40 mg once daily on days 1, 8, 15, and 22; 20 mg for those aged 75 years or older) at each 28-day cycle. The daratumumab plus pomalidomide and dexamethasone group received daratumumab (1800 mg subcutaneously or 16 mg/kg intravenously) weekly during cycles 1 and 2, every 2 weeks during cycles 3-6, and every 4 weeks thereafter until disease progression or unacceptable toxicity. The primary endpoint was progression-free survival in the intention-to-treat population. Safety was analysed in all patients who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov, NCT03180736.Findings: Between June 22, 2017, and June 13, 2019, 304 patients (median age 67 years [IQR 60-72]; 161 [53%] men and 143 [47%] women) were randomly assigned to the daratumumab plus pomalidomide and dexamethasone group (n=151) or the pomalidomide and dexamethasone group (n=153). At a median follow-up of 16·9 months (IQR 14·4-20·6), the daratumumab plus pomalidomide and dexamethasone group showed improved progression-free survival compared with the pomalidomide and dexamethasone group (median 12·4 months [95% CI 8·3-19·3] vs 6·9 months [5·5-9·3]; hazard ratio 0·63 [95% CI 0·47-0·85], two-sided p=0·0018). The most common grade 3 or 4 adverse events were neutropenia (101 [68%] of 149 patients in the daratumumab plus pomalidomide and dexamethasone group vs 76 [51%] of 150 patients in the pomalidomide and dexamethasone group), anaemia (25 [17%] vs 32 [21%]), and thrombocytopenia (26 [17%] vs 27 [18%]). Serious adverse events occurred in 75 (50%) of 149 patients in the daratumumab plus pomalidomide and dexamethasone group versus 59 (39%) of 150 patients in the pomalidomide and dexamethasone group; pneumonia (23 [15%] vs 12 [8%] patients) and lower respiratory tract infection (18 [12%] vs 14 [9%]) were most common. Treatment-emergent deaths were reported in 11 (7%) patients in the daratumumab plus pomalidomide and dexamethasone group versus 11 (7%) patients in the pomalidomide and dexamethasone group.Interpretation: Among patients with relapsed or refractory multiple myeloma, daratumumab plus pomalidomide and dexamethasone reduced the risk of disease progression or death versus pomalidomide and dexamethasone alone and could be considered a new treatment option in this setting.Funding: European Myeloma Network and Janssen Research and Development. [ABSTRACT FROM AUTHOR]