Cusatuzumab plus azacitidine in newly diagnosed acute myeloid leukaemia ineligible for intensive chemotherapy (CULMINATE): part one of a randomised, phase 2, dose optimisation study.

BACKGROUND: Cusatuzumab, a high-affinity anti-CD70 antibody, has shown preliminary activity as a treatment for acute myeloid leukaemia when combined with azacitidine. We aimed to determine the optimum dose for future trials of cusatuzumab in combination with azacitidine in patients with previously untreated acute myeloid leukaemia who are not eligible for intensive chemotherapy. METHODS: In this randomised, phase 2, open-label, dose-optimisation study we enrolled adult patients aged 18 years or older with newly diagnosed acute myeloid leukaemia not eligible for intensive chemotherapy, and with Eastern Cooperative Oncology Group scores of 0-2, from 40 hospitals and centres across seven countries. In part one of the trial, participants were randomly allocated 1:1 to 10 mg/kg or 20 mg/kg intravenous cusatuzumab on days 3 and 17, combined with subcutaneous or intravenous azacitidine 75 mg/m2 on days 1-7 in 28-day cycles. The primary efficacy outcome was the rate of complete remission in the intention-to-treat group. The two dose cohorts were evaluated independently without between-cohort statistical comparison. Safety analyses were performed in all patients who received one dose of study drug. Part two of the trial was planned to be a single-arm expansion to evaluate cusatuzumab plus azacitidine at the cusatuzumab dose level selected in part one (primary hypothesis ≥35% rate of complete remission vs null hypothesis of 20%); however, changes in the acute myeloid leukaemia treatment landscape during this trial made it unlikely that enrolment to part two of the study would be clinically feasible, so the study stopped at the end of part one. The trial was registered at ClinicalTrials.gov, NCT04023526. FINDINGS: 103 patients were enrolled between Aug 30, 2019, and Feb 25, 2020, and randomly assigned to either cusatuzumab 10 mg/kg (n=51) or 20 mg/kg (n=52). Median follow-up was 7·2 months (IQR 10·7 months). 57 of 103 (55%) patients were male and 46 (45%) patients were female, 78 (76%) were White, one (1%) was Asian, and 24 (23%) did not report their race. In the 10 mg/kg group, complete remission rate was 12% (six of 51 patients; 95% CI 6-23) and in the 20 mg/kg group was 27% (14 of 52; 17-40). Grade 3 or worse treatment-emergent adverse events (TEAEs) were similar between the cusatuzumab 10 mg/kg (n=51) and 20 mg/kg (n=51) cohorts and included thrombocytopenia (24 patients [47%] vs 29 [57%]), anaemia (24 [47%] vs 17 [33%]), and neutropenia (20 [39%] in both cohorts). Serious TEAEs were also similar in the two cohorts (44 [86%] vs 40 [78%]). Treatment-related TEAEs leading to death were reported in both groups (three patients [6%] in the 10 mg/kg group vs one patient [2%] in the 20 mg/kg group); the reported causes of death were pneumonia (n=2) and septic shock (n=2). INTERPRETATION: Although part one of this study was not designed to formally compare the two dose cohorts for efficacy, the totality of clinical data for cusatuzumab studies performed to date indicate that cusatuzumab 20 mg/kg plus azacitidine represents the optimal dose for further studies. A phase 1b study investigating the triple combination of cusatuzumab with venetoclax and azacitidine is underway (NCT04150887). FUNDING: Janssen Research & Development and argenx.

Enasidenib vs conventional care in older patients with late-stage mutant-IDH2 relapsed/refractory AML: a randomized phase 3 trial.

This open-label, randomized, phase 3 trial (NCT02577406) compared enasidenib, an oral IDH2 (isocitrate dehydrogenase 2) inhibitor, with conventional care regimens (CCRs) in patients aged ≥60 years with late-stage, mutant-IDH2 acute myeloid leukemia (AML) relapsed/refractory (R/R) to 2 or 3 prior AML-directed therapies. Patients were first preselected to a CCR (azacitidine, intermediate-dose cytarabine, low-dose cytarabine, or supportive care) and then randomized (1:1) to enasidenib 100 mg per day or CCR. The primary endpoint was overall survival (OS). Secondary endpoints included event-free survival (EFS), time to treatment failure (TTF), overall response rate (ORR), hematologic improvement (HI), and transfusion independence (TI). Overall, 319 patients were randomized to enasidenib (n = 158) or CCR (n = 161). The median age was 71 years, median (range) enasidenib exposure was 142 days (3 to 1270), and CCR was 36 days (1 to 1166). One enasidenib (0.6%) and 20 CCR (12%) patients received no randomized treatment, and 30% and 43%, respectively, received subsequent AML-directed therapies during follow-up. The median OS with enasidenib vs CCR was 6.5 vs 6.2 months (HR [hazard ratio], 0.86; P = .23); 1-year survival was 37.5% vs 26.1%. Enasidenib meaningfully improved EFS (median, 4.9 vs 2.6 months with CCR; HR, 0.68; P = .008), TTF (median, 4.9 vs 1.9 months; HR, 0.53; P < .001), ORR (40.5% vs 9.9%; P <.001), HI (42.4% vs 11.2%), and red blood cell (RBC)-TI (31.7% vs 9.3%). Enasidenib safety was consistent with prior reports. The primary study endpoint was not met, but OS was confounded by early dropout and subsequent AML-directed therapies. Enasidenib provided meaningful benefits in EFS, TTF, ORR, HI, and RBC-TI in this heavily pretreated older mutant-IDH2 R/R AML population.

Pevonedistat plus azacitidine vs azacitidine alone in higher-risk MDS/chronic myelomonocytic leukemia or low-blast-percentage AML.

PANTHER is a global, randomized phase 3 trial of pevonedistat+azacitidine (n = 227) vs azacitidine monotherapy (n = 227) in patients with newly diagnosed higher-risk myelodysplastic syndromes (MDS; n = 324), higher-risk chronic myelomonocytic leukemia (n = 27), or acute myeloid leukemia (AML) with 20% to 30% blasts (n = 103). The primary end point was event-free survival (EFS). In the intent-to-treat population, the median EFS was 17.7 months with pevonedistat+azacitidine vs 15.7 months with azacitidine (hazard ratio [HR], 0.968; 95% confidence interval [CI], 0.757-1.238; P = .557) and in the higher-risk MDS cohort, median EFS was 19.2 vs 15.6 months (HR, 0.887; 95% CI, 0.659-1.193; P = .431). Median overall survival (OS) in the higher-risk MDS cohort was 21.6 vs 17.5 months (HR, 0.785; P = .092), and in patients with AML with 20% to 30% blasts was 14.5 vs 14.7 months (HR, 1.107; P = .664). In a post hoc analysis, median OS in the higher-risk MDS cohort for patients receiving >3 cycles was 23.8 vs 20.6 months (P = .021) and for >6 cycles was 27.1 vs 22.5 months (P = .008). No new safety signals were identified, and the azacitidine dose intensity was maintained. Common hematologic grade ≥3 treatment emergent adverse events were anemia (33% vs 34%), neutropenia (31% vs 33%), and thrombocytopenia (30% vs 30%). These results underscore the importance of large, randomized controlled trials in these heterogeneous myeloid diseases and the value of continuing therapy for >3 cycles. The trial was registered on clinicaltrials.gov as #NCT03268954.

Isatuximab monotherapy in patients with refractory T-acute lymphoblastic leukemia or T-lymphoblastic lymphoma: Phase 2 study.

The poor prognosis of acute T-cell lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL) in older adults and patients with relapsed/refractory illness is an unmet clinical need, as there is no defined standard of care and there are few treatment options. Abnormally elevated CD38 expression in T-ALL and T-LBL is associated with tumor expansion and disease development, making CD38 a potential target for anti-T-ALL and T-LBL treatment. Isatuximab is a monoclonal antibody that binds to a specific epitope on CD38. The purpose of the study was to assess the efficacy and safety of isatuximab monotherapy in a phase 2, multicenter, one-arm, open-label study in patients with relapsed or refractory T-ALL or T-LBL (Clinical Trials.gov identifier NCT02999633). The primary endpoint was to assess the efficacy of isatuximab by overall response rate (ORR). An interim analysis based on the efficacy and safety of isatuximab in the first 19 patients enrolled was scheduled, however only 14 patients were enrolled in the study. No patient achieved complete response (CR) or CR with incomplete peripheral recovery. Most patients (11 [78.6%]) developed progressive disease and had progressive disease as their best response. A total of 10 (71.4%) patients had treatment emergent adverse events considered treatment-related, with infusion reactions as the most frequent drug-related TEAE, occurring in 8 (57.1%) patients. Despite the low efficacy of isatuximab in the current study, it is likely that the use of immunotherapy medication in T-ALL will be expanded through logically targeted approaches, together with advances in the design of T-cell therapy and clinical experience and will provide restorative options beyond chemotherapy and targeted treatments.

Melflufen or pomalidomide plus dexamethasone for patients with multiple myeloma refractory to lenalidomide (OCEAN): a randomised, head-to-head, open-label, phase 3 study.

BACKGROUND: Melphalan flufenamide (melflufen), an alkylating peptide-drug conjugate, plus dexamethasone showed clinical activity and manageable safety in the phase 2 HORIZON study. We aimed to determine whether melflufen plus dexamethasone would provide a progression-free survival benefit compared with pomalidomide plus dexamethasone in patients with previously treated multiple myeloma. METHODS: In this randomised, open-label, head-to-head, phase 3 study (OCEAN), adult patients (aged ≥18 years) were recruited from 108 university hospitals, specialist hospitals, and community-based centres in 21 countries across Europe, North America, and Asia. Eligible patients had an ECOG performance status of 0-2; must have had relapsed or refractory multiple myeloma, refractory to lenalidomide (within 18 months of randomisation) and to the last line of therapy; and have received two to four previous lines of therapy (including lenalidomide and a proteasome inhibitor). Patients were randomly assigned (1:1), stratified by age, number of previous lines of therapy, and International Staging System score, to either 28-day cycles of melflufen and dexamethasone (melflufen group) or pomalidomide and dexamethasone (pomalidomide group). All patients received dexamethasone 40 mg orally on days 1, 8, 15, and 22 of each cycle. In the melflufen group, patients received melflufen 40 mg intravenously over 30 min on day 1 of each cycle and in the pomalidomide group, patients received pomalidomide 4 mg orally daily on days 1 to 21 of each cycle. The primary endpoint was progression-free survival assessed by an independent review committee in the intention-to-treat (ITT) population. Safety was assessed in patients who received at least one dose of study medication. This study is registered with ClinicalTrials.gov, NCT03151811, and is ongoing. FINDINGS: Between June 12, 2017, and Sept 3, 2020, 246 patients were randomly assigned to the melflufen group (median age 68 years [IQR 60-72]; 107 [43%] were female) and 249 to the pomalidomide group (median age 68 years [IQR 61-72]; 109 [44%] were female). 474 patients received at least one dose of study drug (melflufen group n=228; pomalidomide group n=246; safety population). Data cutoff was Feb 3, 2021. Median progression-free survival was 6·8 months (95% CI 5·0-8·5; 165 [67%] of 246 patients had an event) in the melflufen group and 4·9 months (4·2-5·7; 190 [76%] of 249 patients had an event) in the pomalidomide group (hazard ratio [HR] 0·79, [95% CI 0·64-0·98]; p=0·032), at a median follow-up of 15·5 months (IQR 9·4-22·8) in the melflufen group and 16·3 months (10·1-23·2) in the pomalidomide group. Median overall survival was 19·8 months (95% CI 15·1-25·6) at a median follow-up of 19·8 months (IQR 12·0-25·0) in the melflufen group and 25·0 months (95% CI 18·1-31·9) in the pomalidomide group at a median follow-up of 18·6 months (IQR 11·8-23·7; HR 1·10 [95% CI 0·85-1·44]; p=0·47). The most common grade 3 or 4 treatment-emergent adverse events were thrombocytopenia (143 [63%] of 228 in the melflufen group vs 26 [11%] of 246 in the pomalidomide group), neutropenia (123 [54%] vs 102 [41%]), and anaemia (97 [43%] vs 44 [18%]). Serious treatment-emergent adverse events occurred in 95 (42%) patients in the melflufen group and 113 (46%) in the pomalidomide group, the most common of which were pneumonia (13 [6%] vs 21 [9%]), COVID-19 pneumonia (11 [5%] vs nine [4%]), and thrombocytopenia (nine [4%] vs three [1%]). 27 [12%] patients in the melflufen group and 32 [13%] in the pomalidomide group had fatal treatment-emergent adverse events. Fatal treatment-emergent adverse events were considered possibly treatment related in two patients in the melflufen group (one with acute myeloid leukaemia, one with pancytopenia and acute cardiac failure) and four patients in the pomalidomide group (two patients with pneumonia, one with myelodysplastic syndromes, one with COVID-19 pneumonia). INTERPRETATION: Melflufen plus dexamethasone showed superior progression-free survival than pomalidomide plus dexamethasone in patients with relapsed or refractory multiple myeloma. FUNDING: Oncopeptides AB.

Oral ixazomib-dexamethasone vs oral pomalidomide-dexamethasone for lenalidomide-refractory, proteasome inhibitor-exposed multiple myeloma: a randomized Phase 2 trial.

Multiple myeloma (MM) patients typically receive several lines of combination therapy and first-line treatment commonly includes lenalidomide. As patients age, they become less tolerant to treatment, requiring convenient/tolerable/lenalidomide-free options. Carfilzomib and/or bortezomib-exposed/intolerant, lenalidomide-refractory MM patients with ≥2 prior lines of therapy were randomized 3:2 to ixazomib-dexamethasone (ixa-dex) (n = 73) or pomalidomide-dexamethasone (pom-dex) (n = 49) until progression/toxicity. Median progression-free survival (mPFS) was 7.1 vs 4.8 months with ixa-dex vs pom-dex (HR 0.847, 95% CI 0.535-1.341, P = 0.477; median follow-up: 15.3 vs 17.3 months); there was no statistically significant difference between arms. In patients with 2 and ≥3 prior lines of therapy, respectively, mPFS was 11.0 vs 5.7 months (HR 1.083, 95% CI 0.547-2.144) and 5.7 vs 3.7 months (HR 0.686, 95% CI 0.368-1.279). Among ixa-dex vs pom-dex patients, 69% vs 81% had Grade ≥3 treatment-emergent adverse events (TEAEs), 51% vs 53% had serious TEAEs, 39% vs 36% had TEAEs leading to drug discontinuation, 44% vs 32% had TEAEs leading to dose reduction, and 13% vs 13% died on study. Quality of life was similar between arms and maintained during treatment. Ixa-dex represents an important lenalidomide-free, oral option for this heavily pretreated, lenalidomide-refractory, proteasome inhibitor-exposed population.Trial registration: ClinicalTrials.gov number, NCT03170882.

Effect of prior treatments on selinexor, bortezomib, and dexamethasone in previously treated multiple myeloma.

Therapeutic regimens for previously treated multiple myeloma (MM) may not provide prolonged disease control and are often complicated by significant adverse events, including peripheral neuropathy. In patients with previously treated MM in the Phase 3 BOSTON study, once weekly selinexor, once weekly bortezomib, and 40 mg dexamethasone (XVd) demonstrated a significantly longer median progression-free survival (PFS), higher response rates, deeper responses, a trend to improved survival, and reduced incidence and severity of bortezomib-induced peripheral neuropathy when compared with standard twice weekly bortezomib and 80 mg dexamethasone (Vd). The pre-specified analyses described here evaluated the influence of the number of prior lines of therapy, prior treatment with lenalidomide, prior proteasome inhibitor (PI) therapy, prior immunomodulatory drug therapy, and prior autologous stem cell transplant (ASCT) on the efficacy and safety of XVd compared with Vd. In this 1:1 randomized study, enrolled patients were assigned to receive once weekly oral selinexor (100 mg) with once weekly subcutaneous bortezomib (1.3 mg/m2) and 40 mg per week dexamethasone (XVd) versus standard twice weekly bortezomib and 80 mg per week dexamethasone (Vd). XVd significantly improved PFS, overall response rate, time-to-next-treatment, and showed reduced all grade and grade ≥ 2 peripheral neuropathy compared with Vd regardless of prior treatments, but the benefits of XVd over Vd were more pronounced in patients treated earlier in their disease course who had either received only one prior therapy, had never been treated with a PI, or had prior ASCT. Treatment with XVd improved outcomes as compared to Vd regardless of prior therapies as well as manageable and generally reversible adverse events. XVd was associated with clinical benefit and reduced peripheral neuropathy compared to standard Vd in previously treated MM. These results suggest that the once weekly XVd regimen may be optimally administered to patients earlier in their course of disease, as their first bortezomib-containing regimen, and in those relapsing after ASCT.Trial registration: ClinicalTrials.gov (NCT03110562). Registered 12 April 2017. https://clinicaltrials.gov/ct2/show/NCT03110562 .

Effect of age and frailty on the efficacy and tolerability of once-weekly selinexor, bortezomib, and dexamethasone in previously treated multiple myeloma.

Elderly and frail patients with multiple myeloma (MM) are more vulnerable to the toxicity of combination therapies, often resulting in treatment modifications and suboptimal outcomes. The phase 3 BOSTON study showed that once-weekly selinexor and bortezomib with low-dose dexamethasone (XVd) improved PFS and ORR compared with standard twice-weekly bortezomib and moderate-dose dexamethasone (Vd) in patients with previously treated MM. This is a retrospective subgroup analysis of the multicenter, prospective, randomized BOSTON trial. Post hoc analyses were performed to compare XVd versus Vd safety and efficacy according to age and frailty status (<65 and ≥65 years, nonfrail and frail). Patients ≥65 years with XVd had higher ORR (OR 1.77, p = .024), ≥VGPR (OR, 1.68, p = .027), PFS (HR 0.55, p = .002), and improved OS (HR 0.63, p = .030), compared with Vd. In frail patients, XVd was associated with a trend towards better PFS (HR 0.69, p = .08) and OS (HR 0.62, p = .062). Significant improvements were also observed in patients <65 (ORR and TTNT) and nonfrail patients (PFS, ORR, ≥VGPR, and TTNT). Patients treated with XVd had a lower incidence of grade ≥ 2 peripheral neuropathy in ≥65 year-old (22% vs. 37%; p = .0060) and frail patients (15% vs. 44%; p = .0002). Grade ≥3 TEAEs were not observed more often in older compared to younger patients, nor in frail compared to nonfrail patients. XVd is safe and effective in patients <65 and ≥65 and in nonfrail and frail patients with previously treated MM.

Safety and efficacy of talacotuzumab plus decitabine or decitabine alone in patients with acute myeloid leukemia not eligible for chemotherapy: results from a multicenter, randomized, phase 2/3 study.

Talacotuzumab, a humanized anti-CD123 monoclonal antibody, was evaluated in combination with decitabine in elderly patients with acute myeloid leukemia (AML) not eligible for intensive chemotherapy. A multicenter, phase 2/3 study was initiated to determine the recommended phase 2 dose (RP2D) of talacotuzumab (Part A) followed by an open-label, randomized comparison of talacotuzumab in combination with decitabine versus decitabine alone to assess achievement of complete response (CR) and overall survival (OS) in Part B. Ten patients were enrolled in Part A and 316 in Part B; the results presented here are based on a database lock on January 25, 2018. Part A confirmed the RP2D of talacotuzumab to be 9 mg/kg. In Part B, CR was achieved in 12/80 (15%) patients receiving combination therapy and in 9/82 (11%) patients receiving decitabine alone (odds ratio: 1.4; 95% confidence interval [CI]: 0.6-3.6; p = 0.44). Median (95% CI) OS was 5.36 (4.27-7.95) months for combination therapy versus 7.26 (6.47-8.64) months for decitabine alone (hazard ratio: 1.04; 95% CI: 0.79-1.37; p = 0.78). Combination therapy showed no improvement in efficacy versus decitabine alone, resulting in the Independent Data Monitoring Committee's recommendation of early termination of enrollment and discontinuation of talacotuzumab treatment.

Once-per-week selinexor, bortezomib, and dexamethasone versus twice-per-week bortezomib and dexamethasone in patients with multiple myeloma (BOSTON): a randomised, open-label, phase 3 trial.

BACKGROUND: Selinexor combined with dexamethasone has shown activity in patients with heavily pre-treated multiple myeloma. In a phase 1b/2 study, the combination of oral selinexor with bortezomib (a proteasome inhibitor) and dexamethasone induced high response rates with low rates of peripheral neuropathy, the main dose-limiting toxicity of bortezomib. We aimed to evaluate the clinical benefit of weekly selinexor, bortezomib, and dexamethasone versus standard bortezomib and dexamethasone in patients with previously treated multiple myeloma. METHODS: This phase 3, randomised, open-label trial was done at 123 sites in 21 countries. Patients aged 18 years or older, who had multiple myeloma, and who had previously been treated with one to three lines of therapy, including proteasome inhibitors, were randomly allocated (1:1) to receive selinexor (100 mg once per week), bortezomib (1·3 mg/m2 once per week), and dexamethasone (20 mg twice per week), or bortezomib (1·3 mg/m2 twice per week for the first 24 weeks and once per week thereafter) and dexamethasone (20 mg four times per week for the first 24 weeks and twice per week thereafter). Randomisation was done using interactive response technology and stratified by previous proteasome inhibitor therapy, lines of treatment, and multiple myeloma stage. The primary endpoint was progression-free survival 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. The trial is ongoing, with 55 patients remaining on randomised therapy as of Feb 20, 2020. FINDINGS: Of 457 patients screened for eligibility, 402 were randomly allocated-195 (49%) to the selinexor, bortezomib, and dexamethasone group and 207 (51%) to the bortezomib and dexamethasone group-and the first dose of study medication was given between June 6, 2017, and Feb 5, 2019. Median follow-up durations were 13·2 months [IQR 6·2-19·8] for the selinexor, bortezomib, and dexamethasone group and 16·5 months [9·4-19·8] for the bortezomib and dexamethasone group. Median progression-free survival was 13·93 months (95% CI 11·73-not evaluable) with selinexor, bortezomib, and dexamethasone and 9·46 months (8·11-10·78) with bortezomib and dexamethasone (hazard ratio 0·70 [95% CI 0·53-0·93], p=0·0075). The most frequent grade 3-4 adverse events were thrombocytopenia (77 [39%] of 195 patients in the selinexor, bortezomib, and dexamethasone group vs 35 [17%] of 204 in the bortezomib and dexamethasone group), fatigue (26 [13%] vs two [1%]), anaemia (31 [16%] vs 20 [10%]), and pneumonia (22 [11%] vs 22 [11%]). Peripheral neuropathy of grade 2 or above was less frequent with selinexor, bortezomib, and dexamethasone (41 [21%] patients) than with bortezomib and dexamethasone (70 [34%] patients; odds ratio 0·50 [95% CI 0·32-0·79], p=0·0013). 47 (24%) patients in the selinexor, bortezomib, and dexamethasone group and 62 (30%) in the bortezomib and dexamethasone group died. INTERPRETATION: A once-per-week regimen of selinexor, bortezomib, and dexamethasone is a novel, effective, and convenient treatment option for patients with multiple myeloma who have received one to three previous lines of therapy. FUNDING: Karyopharm Therapeutics.

Pharmacokinetic, pharmacodynamic and covariate analysis of subcutaneous versus intravenous administration of bortezomib in patients with relapsed multiple myeloma.

BACKGROUND AND OBJECTIVES: The proteasome inhibitor bortezomib is approved for the treatment of multiple myeloma (MM) and, in the US, for the treatment of mantle cell lymphoma following at least one prior therapy; the recommended dose and schedule is 1.3 mg/m(2) on days 1, 4, 8 and 11 of 21-day cycles, and the approved routes of administration in the US prescribing information are by intravenous and, following a recent update, subcutaneous injection. Findings from a phase III study demonstrated that subcutaneous administration of bortezomib, using the same dose and schedule, resulted in similar efficacy with an improved systemic safety profile (including significantly lower rates of peripheral neuropathy) versus intravenous bortezomib in patients with relapsed MM. The objectives of this report were to present a comprehensive analysis of the pharmacokinetics and pharmacodynamics of subcutaneous versus intravenous bortezomib, and to evaluate the impact of the subcutaneous administration site, subcutaneous injection concentration and demographic characteristics on bortezomib pharmacokinetics and pharmacodynamics. PATIENTS AND METHODS: Data were analysed from the pharmacokinetic substudy of the randomized phase III MMY-3021 study and the phase I CAN-1004 study of subcutaneous versus intravenous bortezomib in patients aged ≥18 (MMY-3021) or ≤75 (CAN-1004) years with symptomatic relapsed or refractory MM after 1-3 (MMY-3021) or ≥1 (CAN-1004) prior therapies. Patients received up to eight 21-day cycles of subcutaneous or intravenous bortezomib 1.3 mg/m(2) on days 1, 4, 8 and 11. Pharmacokinetic and pharmacodynamic (20S proteasome inhibition) parameters of bortezomib following subcutaneous or intravenous administration were evaluated on day 11, cycle 1. RESULTS: Bortezomib systemic exposure was equivalent with subcutaneous versus intravenous administration in MMY-3021 [mean area under the plasma concentration-time curve from time zero to the last quantifiable timepoint (AUC(last)): 155 vs. 151 ng·h/mL; geometric mean ratio 0.992 (90 % CI 80.18, 122.80)] and comparable in CAN-1004 (mean AUC(last): 195 vs. 241 ng·h/mL); maximum (peak) plasma drug concentration (C(max)) was lower with subcutaneous administration in both MMY-3021 (mean 20.4 vs. 223 ng/mL) and CAN-1004 (mean 22.5 vs. 162 ng/mL), and time to C(max) (t(max)) was longer with subcutaneous administration in both studies (median 30 vs. 2 min). Blood 20S proteasome inhibition pharmacodynamic parameters were also similar with subcutaneous versus intravenous bortezomib: mean maximum effect (E(max)) was 63.7 versus 69.3 % in MMY-3021 and 57.0 versus 68.8 % in CAN-1004, and mean area under the effect-time curve from time zero to 72 h was 1,714 versus 1,383 %·h in MMY-3021 and 1,619 versus 1,283 %·h in CAN-1004. Time to E(max) was longer with subcutaneous administration in MMY-3021 (median 120 vs. 5 min) and CAN-1004 (median 120 vs. 3 min). Concentration of the subcutaneous injected solution had no appreciable effect on pharmacokinetic or pharmacodynamic parameters. There were no apparent differences in bortezomib pharmacokinetic and pharmacodynamic parameters between subcutaneous administration in the thigh or abdomen. There were also no apparent differences in bortezomib exposure related to body mass index, body surface area or age. CONCLUSION: Subcutaneous administration results in equivalent bortezomib plasma exposure to intravenous administration, together with comparable blood 20S proteasome inhibition pharmacodynamic effects. These findings, together with the non-inferior efficacy of subcutaneous versus intravenous bortezomib demonstrated in MMY-3021, support the use of bortezomib via the subcutaneous route across the settings of clinical use in which the safety and efficacy of intravenous bortezomib has been established.