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Venetoclax is an approved BCL-2 inhibitor, currently under evaluation in different hematological malignancies in adult and pediatric populations. Venetoclax is available as 10, 50, and 100 mg tablets. To provide an alternative to patients who find taking the commonly prescribed 100 mg tablet a challenge, the interchangeability of lower-strength tablets with the 100 mg tablet was investigated. Additionally, newly developed oral suspension powder formulations to facilitate dosing in pediatrics were evaluated.Pharmacokinetic data from 80 healthy female participants from three phase I studies were utilized to evaluate the bioavailability of (1) 10 and 50 mg tablets relative to a 100 mg tablet; (2) 0.72 and 7.2% (drug to total weight) oral powder formulations relative to the 100 mg tablet; and (3) oral powder formulations administered using different vehicles (apple juice, apple sauce, and yogurt) relative to water under fed conditions.Bioavailability assessments at a 100 mg dose of venetoclax demonstrated bioequivalence across the 10, 50, and 100 mg tablet strengths. Oral powder formulations met the bioequivalence criteria (0.80-1.25) with respect to area under the concentration-time curve to time of the last measurable concentration (AUCThe smaller-sized tablets (10 and 50 mg) and the newly developed oral powder formulations of venetoclax can be used interchangeably with the 100 mg tablets to improve the patients' experience, while maintaining adequate exposure. CLINICAL TRIALS IDENTIFIERS: NCT01682616, 11 September 2012; NCT02005471, 9 December 2013; NCT02242942, 17 September 2014; NCT02203773, 30 July 2014; NCT02287233, 10 November 2014; NCT02993523, 15 December 2016; NCT03069352, 3 March 2017.

This study evaluated venetoclax population pharmacokinetics (popPK) in patients with treatment-naïve acute myeloid leukemia and assessed the relationship between venetoclax exposure and clinical response for venetoclax in combination with either a hypomethylating agent (HMA) or low-dose cytarabine (LDAC). A total of 771 patients who received venetoclax from 5 Phase 1-3 studies were included in the popPK model. Exposure-response analyses included data from 575 patients for venetoclax/placebo plus HMA and 279 patients for venetoclax/placebo plus LDAC. The popPK model successfully characterized venetoclax plasma concentrations over time and confirmed venetoclax exposure did not vary significantly with age, weight, sex, mild to moderate hepatic impairment, or mild to severe renal impairment. Asian patients had 67% higher mean relative bioavailability than non-Asian patients, however the range of exposures in Asian patients was similar to non-Asian patients. For all efficacy endpoints with both treatment combinations, efficacy was higher in the venetoclax treatment groups compared with the respective control arm of placebo plus azacitidine or LDAC. Within patients who received venetoclax, no significant exposure-efficacy relationships were identified for either treatment combination, indicating that the beneficial effects of venetoclax were already maximized in the dose ranges studied. There was no apparent effect of venetoclax exposure on treatment-emergent Grade ≥3 thrombocytopenia or infections for either combination. Rates of treatment-emergent Grade ≥3 neutropenia were higher in the venetoclax treatment arms compared with the respective control arms; however, within patients who received venetoclax, there was only a shallow relationship or no apparent relationship with venetoclax exposure for venetoclax plus HMA or LDAC, respectively. Along with the efficacy and safety data previously published, the exposure-response analyses support the venetoclax dose regimens of 400 mg once daily (QD) plus HMA and 600 mg QD plus LDAC in treatment-naïve AML patients who are ineligible for intensive chemotherapy.

Veliparib (ABT‐888) is a poly(ADP‐ribose) polymerase inhibitor in development for the treatment of high‐grade ovarian cancer or BRCA‐mutated breast cancer in combination with carboplatin and paclitaxel. The population pharmacokinetics of veliparib were characterized using combined data from 1470 adult subjects with ovarian cancer, breast cancer, or other solid tumors enrolled in 6 phase 1 studies, 1 phase 2 study, and 2 phase 3 studies of veliparib oral doses of 10 to 400 mg twice daily as monotherapy or in combination with chemotherapy. A 1‐compartment model with linear clearance and first‐order absorption best characterized veliparib pharmacokinetics. The predicted apparent oral clearance (CL/F) and volume of distribution (Vc/F) were 479 L/day and 152 L, respectively. The significant covariates in the final model included albumin, creatinine clearance, strong inhibitors of cytochrome P450 (CYP) 2D6, and sex on CL/F and albumin, body weight, and sex on Vc/F. Mild and moderate renal impairment increased veliparib median (95%CI) steady‐state AUC (AUCss) by 27.3% (23.7%‐30.9%) and 65.4% (56.0%‐75.5%), respectively, compared with normal renal function. Male subjects had 16.5% (7.53%‐23.9%) lower AUCss compared with female subjects and coadministration with strong CYP2D6 inhibitors increased AUCss by 13.0% (6.11%‐20.8%). Race, age, region, cancer type, or enzyme (CYP3A4, CYP2C19) or transporter (P‐glycoprotein, multidrug and toxin extrusion protein 1/2, organic cation transporter 2) inhibiting/inducing comedications were not found to significantly impact veliparib pharmacokinetics. Other than baseline creatinine clearance and hence renal impairment effect on veliparib clearance, no other covariates had a clinically meaningful effect on veliparib exposure warranting dose adjustment.

Budigalimab is a humanized, recombinant, Fc mutated IgG1 monoclonal antibody targeting programmed cell death 1 (PD‐1) receptor, currently in phase I clinical trials. The safety, efficacy, pharmacokinetics (PKs), pharmacodynamics (PDs), and budigalimab dose selection from monotherapy dose escalation and multihistology expansion cohorts were evaluated in patients with previously treated advanced solid tumors who received budigalimab at 1, 3, or 10 mg/kg intravenously every 2 weeks (Q2W) in dose escalation, including Japanese patients that received 3 and 10 mg/kg Q2W. PK modeling and PK/PD assessments informed the dosing regimen in expansion phase using data from body‐weight‐based dosing in the escalation phase, based on which patients in the multihistology expansion cohort received flat doses of 250 mg Q2W or 500 mg every four weeks (Q4W). Immune‐related adverse events (AEs) were reported in 11 of 59 patients (18.6%), of which 1 of 59 (1.7%) was considered grade ≥ 3 and the safety profile of budigalimab was consistent with other PD‐1 targeting agents. No treatment‐related grade 5 AEs were reported. Four responses per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 were reported in the dose escalation cohort and none in the multihistology expansion cohort. PK of budigalimab was approximately dose proportional and sustained > 99% peripheral PD‐1 receptor saturation was observed by 2 hours postdosing, across doses. PK/PD and safety profiles were comparable between Japanese and Western patients, and exposure‐safety analyses did not indicate any trends. Observed PK and PD‐1 receptor saturation were consistent with model predictions for flat doses and less frequent regimens, validating the early application of PK modeling and PK/PD assessments to inform the recommended dose and regimen, following dose escalation.

Aim To characterize the population pharmacokinetics of a triple direct-acting antiviral (DAA) regimen (3D) (ombitasvir, paritaprevir-ritonavir, and dasabuvir) and adjunctive ribavirin and estimate covariate effects in a broad spectrum of subjects with hepatitis C virus (HCV) genotype 1 infection. Methods Pharmacokinetic data from six phase 3 studies and one phase 2 study in subjects receiving the currently approved doses of the 3D ± ribavirin regimen for treating HCV genotype 1 infection for 12 or 24 weeks were characterized using separate population pharmacokinetic models built using each component of the regimen from non-linear mixed-effects methodology in NONMEM 7.3. In the models, demographic and clinical covariates were tested. Models were assessed via goodness-of-fit plots, visual predictive checks, and bootstrap evaluations. Results The population pharmacokinetic models for each component of the 3D ± ribavirin regimen (DAAs and ritonavir, N = 2348) and ribavirin (N = 1841) adequately described their respective plasma-concentration-time data. Model parameter estimates were precise and robust, and all models showed good predictive performance. Significant covariate effects associated with apparent clearance and volume of distribution included age, body weight, sex, cirrhosis, HCV subtype, opioid or antidiabetic agent use, and creatinine clearance. Conclusion Population pharmacokinetics of the 3D ± ribavirin regimen components in HCV-infected patients were characterized using phase 3 and 2 HCV clinical trial data. Although several statistically significant covariates were identified, their effects were modest and not clinically meaningful to necessitate dose adjustments for any component of the 3D regimen. This article is protected by copyright. All rights reserved.

Introduction: Venetoclax (VEN), an orally bioavailable selective BCL-2 inhibitor, was granted accelerated approval by the FDA for the treatment of acute myeloid leukemia (AML) in combination with a hypomethylating agent (HMA) or low-dose cytarabine (LDAC). The objective of this analysis was to characterize the exposure-efficacy and exposure-safety relationships using data from the nonrandomized Phase 1/2 studies and the confirmatory Phase 3 studies in subjects with treatment-naïve AML who are ineligible for intensive chemotherapy. Methods: A population pharmacokinetic (PK) model for VEN was characterized using data from 771 AML subjects across 5 Phase 1 - 3 studies including subjects with relapsed/refractory AML and subjects with treatment-naïve AML who were ineligible for intensive chemotherapy. PK parameters from this model were used to calculate the exposure metric, the area under the plasma concentration-time curve at steady-state (AUCss), for exposure-efficacy and exposure-safety analyses. Logistic regression and Cox proportional-hazards models were used to characterize the exposure-response relationships for overall survival, event-free survival, and conversion to post-baseline transfusion independence for red blood cells or platelets as well as key safety endpoints of treatment-emergent Grade ≥ 3 neutropenia, thrombocytopenia, and infections. Additionally, best overall response of complete remission (CR), CR + CR with incomplete blood count recovery (CRi), and CR + CR with partial hematological recovery (CRh) were also characterized in the exposure-response analyses. Separate analyses were performed for VEN + HMA and VEN + LDAC, including subjects taking placebo (PBO) + HMA or PBO + LDAC, respectively, to inform the intercepts. A total of 575 subjects with treatment-naïve AML were included in the exposure-response analyses for VEN + HMA and 279 subjects with treatment-naïve AML were included in the exposure-response analyses for VEN + LDAC. Results: VEN + HMA: For all efficacy endpoints studied, there was a clear trend for higher efficacy in subjects treated with VEN + HMA as compared to PBO in combination with azacitidine (AZA). When PBO patients were included, significant exposure-response relationships between VEN exposure and overall survival and event-free survival were identified, and a maximal effect (Emax) model best described the statistically significant positive relationships between VEN exposure and best overall response of CR + CRi and CR + CRh. However, there were no apparent relationships between VEN exposure and any efficacy endpoint without the inclusion of PBO subjects, suggesting that the beneficial effect of VEN is already maximized in the dose range studied (400 to 1200 mg daily [QD]). No exposure-response relationship was identified between VEN exposure and treatment-emergent Grade ≥ 3 thrombocytopenia or infections. An Emax model best described the statistically significant relationship between VEN exposure and treatment-emergent Grade ≥ 3 neutropenia, consistent with the clinical finding that subjects in the VEN + HMA treatment arms had higher rates of reported neutropenia than those in the PBO + AZA arm. VEN + LDAC: For all efficacy endpoints studied, there was a clear trend for higher efficacy in subjects treated with VEN + LDAC as compared to PBO + LDAC. With PBO subjects included, an Emax model best described the statistically significant relationships between VEN exposure and best overall response of CR, CR + CRi, and CR + CRh, with probability of response plateauing at exposures corresponding to 600 mg QD of VEN. There were no apparent relationships between VEN exposure and any efficacy endpoint when the PBO subjects were excluded from analysis, indicating that the beneficial effect of VEN is already maximized at 600 mg QD. Although reported rates of treatment-emergent Grade ≥ 3 neutropenia were higher in the VEN + LDAC treatment arms as compared to PBO + LDAC, no significant exposure-response relationships were found between VEN exposure and treatment-emergent Grade ≥ 3 neutropenia, thrombocytopenia, or infections. Conclusion: The VEN exposure-efficacy and exposure-safety analyses confirm the benefit of adding VEN to either HMA or LDAC and support the dose regimens of VEN 400 mg QD in combination with an HMA and VEN 600 mg QD in combination with LDAC in treatment-naïve AML patients who are ineligible for intensive chemotherapy. Disclosures Eckert: AbbVie Inc.: Current Employment, Other: may hold stock or other options. Brackman:AbbVie Inc.: Current Employment, Other: may hold stock or other options. Menon:AbbVie Inc.: Current Employment, Other: may hold stock or other options. Salem:AbbVie Inc.: Current Employment, Other: may hold stock or other options. Potluri:AbbVie: Current Employment, Other: may hold stock or stock options. Smith:Pfizer: Consultancy; Novartis: Consultancy; Celgene: Consultancy; Jazz Pharmaceuticals: Consultancy; Agios: Consultancy. Wei:AbbVie Inc.: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Astellas: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; MacroGenics: Consultancy, Honoraria; Servier: Consultancy, Honoraria, Research Funding; Walter and Eliza Hall Institute: Other: former employee and receives a fraction of its royalty stream related to venetoclax; Pfizer: Honoraria; Genentech: Honoraria; Astra Zeneca: Honoraria, Research Funding. Hayslip:Abbvie Inc: Current Employment, Other: may hold stock or other options. Miles:Genentech Inc.: Current Employment, Current equity holder in publicly-traded company. Mensing:AbbVie Inc.: Current Employment, Other: may hold stock or other options. Gopalakrishnan:AbbVie Inc.: Current Employment, Other: may hold stock or other options. Zha:AbbVie Inc.: Current Employment, Other: may hold stock or other options.

Minimal residual disease (MRD) is an important clinical endpoint in chronic lymphocytic leukemia (CLL) because it correlates with progression free survival and overall survival. The objective of this work is to investigate the impact of venetoclax (VEN) exposures on undetectable MRD rates in blood and bone marrow (BM) in relapsed/refractory (R/R) CLL patients receiving VEN monotherapy or combination therapy with rituximab (RTX). Data from a total of 708 patients from four VEN monotherapy studies and one combination Phase 1b study (VEN + 6-9 cycles of RTX) in R/R CLL patients were utilized to perform this analysis. The median number of prior therapies in these studies was 3, 42% of the patients had 17p chromosomal deletion and 28% had prior B-Cell Receptor inhibitor (BCRi) therapy. Blood and BM MRD assessments were available for 70% and 38%, respectively, of patients included in the analysis. Absence of an MRD measurement was assumed as detectable MRD for the purposes of this analysis. The average concentration (Cavg) of VEN was computed for each patient by fitting a population pharmacokinetic model to the observed VEN concentration data. The model was used to calculate area under the curve and compute Cavg accounting for VEN dose ramp-ups, reductions and interruptions. The relationships between venetoclax Cavg and undetectable MRD rates were assessed by using quartile plots. Logistic regression analyses were also conducted to quantify the exposure-response relationship. With VEN monotherapy, the undetectable MRD rates in blood and BM increased with the increase in VEN exposures. With VEN + RTX combination treatment, the undetectable MRD rates in blood and BM showed an increase with increasing VEN average concentration, but the benefit saturated with limited increase at exposures beyond 400mg. Logistic regression analyses indicated statistically significant (p These results demonstrate that higher venetoclax concentrations are associated with higher undetectable MRD rates in both blood and BM. When VEN is combined with RTX, an increase in VEN dose beyond 400mg is unlikely to result in higher undetectable MRD rates. Citation Format: Sathej Gopalakrishnan, Rajeev Menon, Brenda Chyla, Divya Samineni, Amanda Jacobson, Su Young Kim, Sven Mensing, Ahmed Hamed Salem. Relationship between venetoclax concentrations and undetectable MRD in patients with chronic lymphocytic leukemia [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3024.

Direct-acting antiviral agents (DAAs) are established as the standard of care for chronic hepatitis C virus (HCV) infection. One of the newest additions to the HCV arsenal is an oral three-DAA combination therapy (i.e., the 3D regimen) that does not require concomitant use of pegylated interferon. The clinical development program for the 3D regimen has yielded a robust dataset that is inclusive of various dosing schemes and a diverse patient population. Using data from nine phase 1b/2a/2b studies that enrolled patients with HCV genotype 1 infection, population pharmacokinetic models were developed for each component of the 3D regimen (ombitasvir, paritaprevir, ritonavir, and dasabuvir) and for ribavirin, an adjunctive therapy used to enhance therapeutic efficacy in some populations. Formulation effects, accumulation, relative bioavailability, and interactions between DAAs were assessed during model development, and demographic and clinical covariates were identified and evaluated for their effects on drug exposures. Proposed models were assessed via goodness-of-fit plots, visual predictive checks, and bootstrap evaluations. Population pharmacokinetic models adequately described their respective plasma concentration-time data with precise and reliable model parameter estimates and with good predictive performance. Covariates, including age, sex, body weight, cytochrome P450 2C8 inhibitor use, non-Hispanic ethnicity, and creatinine clearance, were associated with apparent clearance and/or apparent volume parameters; however, the magnitude of effect on drug exposure was modest and not considered to be clinically significant. No patient-related or clinical parameters were identified that would necessitate dose adjustment of the 3D regimen in patients with HCV genotype 1 infection.

Introduction: Venetoclax, a selective BCL2 inhibitor, is approved for treatment of chronic lymphocytic leukemia in patients who received at least one prior therapy and is being studied in several other hematological malignancies including acute myeloid leukemia (AML). The objective of this analysis was to characterize the exposure-efficacy and exposure-safety relationships of venetoclax in patients with newly diagnosed AML who are not eligible for standard anthracycline-based induction therapy treated with venetoclax plus a hypomethylating agent (HMA) either azacitidine or decitabine, or low dose cytarabine (LDAC) to inform dose selection. Methods: A population pharmacokinetic model for venetoclax was developed using data from 336 AML subjects. Post hoc pharmacokinetic parameters generated from the model were used to calculate the exposure metric, steady-state area under the plasma concentration-time curve (AUCss), in the exposure-efficacy and exposure-safety analyses. Multivariate cumulative logistic regression analyses were performed using efficacy and safety data. In total, for the venetoclax plus HMA combination, 201 subjects were included in the exposure-efficacy and 212 subjects were included in the exposure-safety analyses. For the venetoclax plus LDAC combination, 83 subjects were included in the exposure-efficacy and 92 subjects were included in the exposure-safety analyses. Predictions based on the exposure-response model parameter estimates were used to explore the exposure- and dose-response relationships and select the optimal venetoclax dose. Results: Venetoclax in Combination with HMAs: Simulations indicated that venetoclax dosage of 400 mg once daily (QD) in combination with HMAs maximizes the probability of a typical subject achieving a response of complete remission (CR).. Venetoclax exposure-response relationship was similar for both azacitidine and decitabine combination (P > 0.05). For exposure-safety analyses, only treatment-emergent Grade ≥ 3 infections showed a statistically significant relationship with venetoclax exposures in combination with HMAs across the tested venetoclax dose range (400 - 1200 mg QD). The probability of occurrence of treatment-emergent Grade ≥ 3 infections at venetoclax dose of 400 mg and 800 mg was 51% (95% CI: [43, 58%]) and 59% (95% CI: [50, 66%]), respectively. Venetoclax in Combination with LDAC: A statistically significant association of best responses was determined with increasing steady-state area under the plasma concentration-time curve (AUCss). Based on the tolerability data, the probability of achieving CR with incomplete count recovery (CRi) or better, and CR was predicted for doses up to 600 mg. The predicted probability of achieving CRi or better was approximately 46% (95% CI: [37, 55%]) and 55% (95% CI: [45 - 66%]) at exposures associated with the 400 mg and 600 mg dosage regimen given once daily, respectively. Conclusions: The venetoclax exposure- efficacy and exposure-safety analyses supported the 400 mg QD dosage regimen of venetoclax in combination with the HMAs and 600 mg QD dosage regimen of venetoclax in combination with LDAC in treatment naïve AML patients who are ineligible for standard induction chemotherapy. Disclosures Agarwal: AbbVie: Employment, Equity Ownership. Gopalakrishnan:AbbVie: Employment, Equity Ownership. Mensing:AbbVie: Employment, Equity Ownership. Potluri:AbbVie: Employment, Equity Ownership. Hayslip:AbbVie: Employment, Equity Ownership. Friedel:AbbVie: Employment, Equity Ownership. Menon:AbbVie: Employment, Equity Ownership. Salem:AbbVie: Employment, Equity Ownership.

Venetoclax is a selective, potent, orally bioavailable, small molecule, B-cell lymphoma-2 (Bcl–2) inhibitor that restores apoptosis in cancer cells. Clinical efficacy of venetoclax has been observed in a variety of hematological malignancies, including chronic lymphocytic leukemia (CLL) and non-Hodgkins lymphoma (NHL). The objective of this research was to characterize the relationship between venetoclax exposures and efficacy in relapsed or refractory (R/R) CLL/small lymphocytic lymphoma (SLL) subjects, as well as safety in R/R CLL/SLL and NHL subjects. A total of 272 and 444 subjects from 4 clinical studies were included in the exposure-efficacy and exposure-safety analyses, respectively. Characteristics evaluated for their impact on efficacy and safety included: demographics (bodyweight, sex, etc.), baseline disease characteristics (e.g. lymphocyte count, tumor size, 17p del somatic mutation), and select co-medications. Model based simulations indicated that a venetoclax dosage of 400 mg daily maximized the probability of a typical subject with R/R CLL/SLL achieving an objective response (OR) by 6 months of venetoclax treatment with estimated OR rates of 80.9% (95% confidence interval [CI]: [77.5% - 84.0%]), 84.8% (95% CI: [81.5% - 88.0%]), and 85.5% (95% CI: [82.6% - 88.4%]) at the 200, 400, and 600 mg dosage regimens, respectively. The 17p deletion was not identified in any of the exposure-efficacy analyses to be related to the responsiveness of R/R CLL/SLL subjects to venetoclax. Therefore, subjects with the 17p deletion chromosomal aberration appear to be as sensitive to the effects of venetoclax as subjects who do not have the 17p deletion, consistent with its Bcl-2 inhibitor mechanism of action that bypasses the signaling events associated with the 17p deletion. The safety analyses of the adverse events (Grade ≥ 3) of neutropenia and infection in R/R CLL/SLL and NHL subjects both indicated that higher average venetoclax concentrations were associated with a decrease in adverse events, indicating that these evaluated safety endpoints are not dose-limiting. Sensitivity analyses supported that increasing venetoclax concentration did not increase these adverse events. It is hypothesized that the association is driven by disease improvement with venetoclax treatment and not by directly affecting neutrophils or granulocyte progenitor cells. Overall, the exposure-response-safety analyses indicated that a venetoclax dosage regimen of 400 mg daily maximizes (>80%) the probability of achieving objective response in R/R CLL/SLL subjects with minimal probability of neutropenia or infection. Citation Format: Kevin J. Freise, Aksana K. Jones, Doerthe Eckert, Sven Mensing, Shekman Wong, Rod Humerickhouse, Walid Awni, Ahmed H. Salem. Relationship of venetoclax dose and exposure to response in relapsed or refractory chronic lymphocytic leukemia and non-Hodgkin's lymphoma subjects. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2045.