Ixazomib, the first oral proteasome inhibitor, is approved in combination with lenalidomide and dexamethasone for the treatment of patients with multiple myeloma (MM) who have received at least one ...prior therapy. Ixazomib is a selective, potent, and reversible inhibitor of the 20S proteasome, and preferentially binds to and inhibits the β5 chymotrypsin-like proteolytic site. Ixazomib absorption is rapid, with a median time to reach maximum plasma concentration of approximately 1 h post-dose. Ixazomib pharmacokinetics (PK) are adequately described by a three-compartment model (terminal half-life of 9.5 days) with first-order linear absorption (oral bioavailability of 58%). Plasma exposures of ixazomib increase in a dose-proportional manner. A high-fat meal decreases both the rate and extent of ixazomib absorption, supporting administration on an empty stomach. Population PK analyses demonstrated that no dose adjustment is required based on age, body size/weight, race, sex, mild-to-moderate renal impairment, or mild hepatic impairment. Results from dedicated studies indicate that a reduced starting dose (from 4 to 3 mg) is appropriate for patients with severe renal impairment, end-stage renal disease requiring dialysis, or moderate-to-severe hepatic impairment. Non-cytochrome P450 (CYP)-mediated metabolism appears to be the major clearance mechanism for ixazomib. Drug–drug interaction studies have shown no meaningful effects of strong inhibitors of CYP3A on ixazomib PK; however, the strong inducer rifampin caused a clinically relevant reduction in ixazomib exposure, supporting the recommendation to avoid concomitant administration of ixazomib with strong CYP3A inducers. Exposure–response analyses of data from the phase III TOURMALINE-MM1 registrational study demonstrate a favorable benefit–risk profile for the approved dose and regimen of weekly ixazomib 4 mg on days 1, 8, and 15 of each 28-day cycle.
TOURMALINE-MM1, the only blinded randomized study in patients with relapsed and/or refractory multiple myeloma (RRMM; ≥1 prior therapy) in the last 10 years, investigated ...ixazomib+lenalidomide+dexamethasone (IRd) versus lenalidomide+dexamethasone (Rd). Final overall survival (OS) data were based on a median follow-up of 85 months. In RRMM trials where patients have had 1-3 relapses after initial treatment, a high proportion receive subsequent therapy. Application of salvage therapies in blinded trials and newer modes of therapy can increasingly complicate the interpretation of OS. This analysis explores the impact of subsequent therapies on OS outcomes in TOURMALINE-MM1. The inverse probability of censoring weights (IPCW) method, marginal structural model (MSM), and rank preserving structural failure time model (RPSFTM) were utilized to adjust for confounding on OS, introduced by subsequent therapies. Analyses were conducted for the intentto-treat (ITT) population and ≥2 prior lines subgroup. Unadjusted hazard ratio (HR) for IRd versus Rd was 0.94 (95% confidence interval CI: 0.78-1.13) in the ITT population. After adjusting for the impact of subsequent therapies by the RPSFTM method, estimated HR for IRd versus Rd in the ITT population was 0.89 (95% CI: 0.74-1.07). Adjusting with IPCW and MSM methods also showed an improvement in HR, favoring IRd. IRd may be particularly beneficial in patients with ≥2 prior lines of therapy (IPCW and MSM HR=0.52, 95% CI: 0.30-0.88; RPSFTM HR=0.68, 95% CI: 0.51-0.91). These analyses highlight the growing challenge of demonstrating OS benefit in multiple myeloma patients and the importance of assessing confounding introduced by subsequent therapies when interpreting OS.
Summary
Transfusional iron overload represents a substantial challenge in the management of patients with sickle cell disease (SCD) who receive chronic or episodic red blood cell transfusions. ...Iron‐induced cardiomyopathy is a leading cause of death in other chronically transfused populations but rarely seen in SCD. Study objectives were to: (i) examine the extent of myocardial and hepatic siderosis using magnetic resonance imaging (MRI) in chronically transfused SCD patients, and (ii) evaluate the relationship between long‐term (over the 5 years prior to enrolment) mean serum ferritin (MSF), spot‐ferritin values and liver iron content (LIC) measured using MRI and liver biopsy. Thirty‐two SCD patients (median age 15 years) with transfusional iron overload were recruited from two U.S. institutions. Long‐term MSF and spot‐ferritin values significantly correlated with LIC by MRI‐R2* (r = 0·77, P < 0·001; r = 0·82, P < 0·001, respectively). LIC by MRI‐R2* had strong positive correlation with LIC by liver biopsy (r = 0·98, P < 0·001) but modest inverse correlation with cardiac MRI‐T2* (r = −0·41, P = 0·02). Moderate to severe transfusional iron overload in SCD was not associated with aberrations in other measures of cardiac function based on echocardiogram or serum biomarkers. Our results suggest that SCD patients receiving chronic transfusions may not demonstrate significant cardiac iron loading irrespective of ferritin trends, LIC and erythropoiesis suppression.
•Secondary analysis of age and frailty patient subgroups enrolled in TOURMALINE-MM4.•PFS benefit with ixazomib versus placebo in age subgroups: < 65, 65-74, and ≥ 75 years.•PFS benefit seen in ...frailty subgroups: fit, intermediate-fit, and frail patients.•AE and discontinuation rates were higher or similar with ixazomib across subgroups.•Patient quality-of-life was similar between ixazomib and placebo across subgroups.
The TOURMALINE-MM4 trial demonstrated a significant and clinically meaningful progression-free survival (PFS) benefit with ixazomib versus placebo as postinduction maintenance in nontransplant, newly-diagnosed multiple myeloma patients, with a manageable and well-tolerated toxicity profile.
In this subgroup analysis, efficacy and safety were assessed by age (< 65, 65-74, and ≥ 75 years) and frailty status (fit, intermediate-fit, and frail).
In this analysis, PFS benefit with ixazomib versus placebo was seen across age subgroups, including patients aged < 65 years (hazard ratio HR, 0.576; 95% confidence interval CI, 0.299-1.108; P = .095), 65-74 years (HR, 0.615; 95% CI, 0.467-0.810; P < .001), and ≥ 75 years (HR, 0.740; 95% CI, 0.537-1.019; P = .064). PFS benefit was also seen across frailty subgroups, including fit (HR, 0.530; 95% CI, 0.387-0.727; P < .001), intermediate-fit (HR, 0.746; 95% CI, 0.526-1.058; P = .098), and frail (HR, 0.733; 95% CI, 0.481-1.117; P = .147) patients. With ixazomib versus placebo, rates of grade ≥ 3 treatment-emergent adverse events (TEAEs; 28-44% vs. 10-36%), serious TEAEs (15-29% vs. 3-29%), and discontinuation due to TEAEs (7-19% vs. 5-11%) were higher or similar across age and frailty subgroups, and generally somewhat higher in older age groups and intermediate-fit/frail patients in both arms. Treatment with ixazomib versus placebo did not adversely affect patient-reported quality-of-life scores across age and frailty status subgroups.
Ixazomib is a feasible and effective maintenance option for prolonging PFS across this heterogeneous patient population.
This TOURMALINE-MM4 secondary analysis was performed to determine if the progression-free survival (PFS) benefit observed in newly-diagnosed multiple myeloma (NDMM) patients with maintenance ixazomib versus placebo was driven by a particular subgroup of patients. PFS benefit with ixazomib versus placebo was seen across all age and frailty status subgroups. Ixazomib prolonged PFS across the heterogeneous population of NDMM patients.
Display omitted
Ixazomib is an oral proteasome inhibitor approved in combination with lenalidomide and dexamethasone for the treatment of relapsed/refractory multiple myeloma (MM). Approval in the United States, ...Europe, and additional countries was based on results from the phase III TOURMALINE‐MM1 (C16010) study. Here, joint population pharmacokinetic/pharmacodynamic time‐to‐event (TTE) and discrete time Markov models were developed to describe key safety (rash and diarrhea events, and platelet counts) and efficacy (myeloma protein M‐protein and progression‐free survival PFS) outcomes observed in TOURMALINE‐MM1. Models reliably described observed safety and efficacy results; prior immunomodulatory drug therapy and race were significant covariates for diarrhea and rash events, respectively, whereas M‐protein dynamics were sufficiently characterized using TTE models of relapse and dropout. Moreover, baseline M‐protein was identified as a significant covariate for observed PFS. The developed framework represents an integrated approach to describing safety and efficacy with MM therapy, enabling the simulation of prospective trials and potential alternate dosing regimens.
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.
Membrane-spanning proteins may interact with a variety of other integral and peripheral membrane proteins via a diversity of protein-protein interactions. Not surprisingly, defects or mutations in ...any one of these interacting components can impact the physical and biological properties on the entire complex. Here we use quantum dots to image the diffusion of individual band 3 molecules in the plasma membranes of intact human erythrocytes from healthy volunteers and patients with defects in one of their membrane components, leading to well-known red cell pathologies (hereditary spherocytosis, hereditary elliptocytosis, hereditary hydrocytosis, Southeast Asian ovalocytosis, and hereditary pyropoikilocytosis). After characterizing the motile properties of the major subpopulations of band 3 in intact normal erythrocytes, we demonstrate that the properties of these subpopulations of band 3 change significantly in diseased cells, as evidenced by changes in the microscopic and macroscopic diffusion coefficients of band 3 and in the compartment sizes in which the different band 3 populations can diffuse. Because the above membrane abnormalities largely arise from defects in other membrane components (eg, spectrin, ankyrin), these data suggest that single particle tracking of band 3 might constitute a useful tool for characterizing the general structural integrity of the human erythrocyte membrane.
Some cytogenetic abnormalities (CAs) are associated with poorer prognosis in multiple myeloma (MM); proteasome inhibitors appear to benefit patients with high-risk CAs. We evaluated 2247 MM patients ...from the TOURMALINE-MM1/-MM2/-MM3/-MM4 trials to assess the PFS benefit of ixazomib plus lenalidomide-dexamethasone (Rd) vs placebo-Rd (TOURMALINE-MM1/-MM2) or ixazomib vs placebo (TOURMALINE-MM3/-MM4) in specific high-risk CAs. After a pooled median follow-up of 25.6 months, the hazard ratio (HR) for PFS with ixazomib- vs placebo-based therapy for high-risk patients was 0.74 (95% confidence interval CI: 0.59-0.93; median PFS mPFS 17.8 vs 13.2 months), and 0.70 (95% CI: 0.62-0.80; mPFS 26.3 vs 17.6 months) for complementary standard-risk patients. The HR for expanded high-risk patients was 0.75 (95% CI: 0.64-0.87; mPFS 18.1 vs 14.1 months), and 0.71 (95% CI: 0.59-0.85; mPFS 36.1 vs 21.4 months) for complementary standard-risk patients. The HR for PFS with ixazomib- vs placebo-based therapy was 0.68 in patients with t(4;14) (95% CI: 0.48-0.96; mPFS 22.4 vs 13.2 months), and 0.77 for patients with amp1q21 (95% CI: 0.63-0.93; mPFS 18.8 vs 14.5 months). A PFS benefit was demonstrated with ixazomib- vs placebo-based therapy regardless of cytogenetic status, with greatest benefit observed in patients with t(4;14) and amp1q21.
Ixazomib‐lenalidomide‐dexamethasone (ixazomib‐Rd) showed clinical efficacy over placebo‐Rd in patients with relapsed/refractory multiple myeloma (MM) in the TOURMALINE‐MM1 trial. Over a median ...follow‐up of ∼85 months, as patients showed disease progression, they received subsequent novel therapies that confounded the overall survival (OS) benefit. Here, we conducted a post hoc analysis in 148 patients from seven countries defined as emerging markets, with limited access to novel therapies for MM during the trial period, to describe the impact of these therapies on OS. Patients were randomised to ixazomib‐Rd (n = 71) or placebo‐Rd (n = 77). The median progression‐free survival (PFS) was 18.7 versus 10.2 months, with ixazomib‐Rd versus placebo‐Rd (hazard ratio HR, 0.504; p = 0.008) demonstrating a statistically significant improvement as observed in the primary trial. The median OS improved by 32.6 months with ixazomib‐Rd over placebo‐Rd (63.5 vs. 30.9 months; HR, 0.794; p = 0.261); however, the statistically significant benefit seen in PFS was not observed for OS. Improvement with ixazomib‐Rd over placebo‐Rd was observed in overall response (81.7% vs. 64.9%; odds ratio OR, 2.38; p = 0.019) and complete response (22.5% vs. 3.9%; OR, 7.57; p < 0.001). Patient‐reported quality of life and use of subsequent therapies were similar across treatment groups. No new safety concerns were identified. Compared with the main cohort, median OS was 10 months longer with ixazomib‐Rd and 21 months shorter with placebo‐Rd in this subgroup, indicating a clinically meaningful survival benefit of ixazomib‐Rd treatment in this patient population with limited access to subsequent novel therapies.
Summary
Acute chest syndrome (ACS) is defined as fever, respiratory symptoms and a new pulmonary infiltrate in an individual with sickle cell disease (SCD). Nearly half of ACS episodes occur in SCD ...patients already hospitalized, potentially permitting pre‐emptive therapy in high‐risk patients. Simple transfusion of red blood cells may abort ACS if given to patients hospitalized for pain who develop fever and elevated levels of secretory phospholipase A2 (sPLA2). In a feasibility study (PROACTIVE; ClinicalTrials.gov NCT00951808), patients hospitalized for pain who developed fever and elevated sPLA2 were eligible for randomization to transfusion or observation; all others were enrolled in an observational arm. Of 237 enrolled, only 10 were randomized; one of the four to receive transfusion had delayed treatment. Of 233 subjects receiving standard care, 22 developed ACS. A threshold level of sPLA2 ≥ 48 ng/ml gave optimal sensitivity (73%), specificity (71%) and accuracy (71%), but a positive predictive value of only 24%. The predictive value of sPLA2 was improved in adults and patients with chest or back pain, lower haemoglobin concentration and higher white blood cell counts, and in those receiving less than two‐thirds maintenance fluids. The hurdles identified in PROACTIVE should facilitate design of a larger, definitive, phase 3 randomized controlled trial.
PDF
