Venetoclax in biomarker-selected multiple myeloma patients: Impact of exposure on clinical efficacy and safety.

Venetoclax, a potent BCL-2 inhibitor, is currently under development for treatment of t(11;14) Multiple myeloma (MM). The objective of this research was to investigate the exposure-response relationships of venetoclax for a phase 1/2 study evaluating venetoclax monotherapy or in combination with dexamethasone in relapsed or refractory MM. A total of 117 patients receiving venetoclax at 300, 600, 800, 900, or 1200 mg were included in the analysis. The impact of venetoclax exposures on efficacy (objective response rate [ORR], progression-free survival [PFS] and overall survival [OS]) as well as safety (treatment-emergent adverse effects (grade ≥3) of neutropenia, infection, and any grade of serious treatment-emergent adverse effects) was evaluated. In the t(11;14)-positive subpopulation, venetoclax exposure relationships to PFS and OS indicated a trend of longer PFS and OS with higher exposures. Moreover, logistic regression analyses for clinical response (ORR and ≥VGPR rate) demonstrated a statistically significant (p < 0.05) relationship with exposure. Evaluation of the exposure-safety relationships demonstrated a lack of a relationship between venetoclax exposures (AUCavg ) and grade ≥3 infections, grade ≥3 neutropenia, grade ≥3 treatment-emergent adverse events or any grade serious treatment-emergent adverse events. These findings support further study of venetoclax at 800 mg QD dose in combination with dexamethasone in the t(11;14)-positive patient population where increased efficacy was observed without an increase in safety events.Clinical Trial: NCT01794520 registered 20 February 2013.

Venetoclax pharmacokinetics in participants with end-stage renal disease undergoing haemodialysis.

AIMS: Renal insufficiency is a common comorbidity in patients with haematological malignancies. This study aimed to assess how end-stage renal disease (ESRD) might affect the pharmacokinetics of venetoclax, a Bcl-2 inhibitor, in participants with ESRD undergoing haemodialysis. METHODS: Venetoclax was administered as a single 100-mg dose to 6 female participants with ESRD (estimated glomerular filtration rate <15 mL/min) both prior to haemodialysis and between haemodialysis days and 7 healthy female participants with normal renal function (estimated glomerular filtration rate >90 mL/min). Intensive pharmacokinetic and protein binding samples were collected from all participants. Arterial and venous samples were collected from ESRD participants during haemodialysis to assess the effect of haemodialysis on venetoclax pharmacokinetics. Pharmacokinetic parameters were estimated using noncompartmental methods. RESULTS: There was no difference in plasma venetoclax concentrations between arterial and venous samples, suggesting that haemodialysis did not affect the pharmacokinetics of venetoclax. The fraction unbound (fu ) of venetoclax was ~2-fold higher for participants with ESRD compared to participants with normal renal function. The unbound maximum plasma concentration and area under the plasma concentration-time curve from time 0 to 48 h were comparable between ESRD and normal function groups. The mean half-life ranged from 10.4 to 12.2 h across groups, demonstrating that ESRD did not affect the half-life of venetoclax. No new safety signals were observed during this study. CONCLUSION: ESRD and dialysis do not alter unbound venetoclax plasma concentrations. No pharmacokinetics driven dose adjustment is needed for patients with renal insufficiency.

A phase 2 study of ibrutinib in combination with bortezomib and dexamethasone in patients with relapsed/refractory multiple myeloma.

OBJECTIVE: We evaluated ibrutinib, a once-daily inhibitor of Bruton's tyrosine kinase, combined with bortezomib and dexamethasone in patients with relapsed or relapsed/refractory multiple myeloma who had received 1-3 prior therapies. METHODS: This was a phase 2, single-arm, open-label, multicentre study (NCT02902965). The primary endpoint was progression-free survival (PFS). RESULTS: Seventy-six patients were enrolled; 74 received ≥1 dose of study treatment. After median follow-up of 19.6 months, median PFS was 8.5 months (95% CI: 6.2-10.8); median overall survival was not reached. Overall response rate was 57% (95% CI: 45-68), and median duration of response was 9.5 months (95% CI: 6.9-10.6). Grade 3/4 AEs occurred in 73% of patients and fatal AEs occurred in 15% of patients. Incidence of major haemorrhage was 5%; one patient died from cerebral haemorrhage. After an observed increased incidence of serious (42%) and fatal (11%) infections, enrolment was suspended to implement risk-minimisation measures. The safety profile was otherwise consistent with known safety profiles of the individual drugs. CONCLUSION: Ibrutinib combined with bortezomib and dexamethasone elicited clinical responses. However, efficacy assessments conducted at potential restart of enrolment indicated that the targeted PFS could not be reached with additional patient enrolment, and the study was terminated.