Use of Real-World Evidence in a Virtual Bridging Analysis for a Human Epidermal Growth Factor Receptor 2-Targeted Antibody-Drug Conjugate in Gastric Cancer.

This study bridged pharmacokinetic, efficacy, and safety clinical trial data from Japan to a Western population using real-world evidence (RWE) to investigate the antibody-drug conjugate trastuzumab deruxtecan (T-DXd) in the treatment of human epidermal growth factor receptor 2 (HER2)-positive advanced gastric cancer. Using population pharmacokinetic and exposure-response (efficacy/safety) models, exposure-efficacy data from 117 patients and exposure-safety data from 158 patients in Japan who received T-DXd 6.4 mg/kg as second-line or later treatment were bridged to RWE including covariate information from 25 Western patients with HER2-positive gastric cancer who received second-line or later T-DXd treatment. Pharmacokinetic simulations indicated that intact T-DXd and released drug (DXd) steady-state exposures were comparable between Western patients and patients from Japan; the Western/Japan ratio of exposure medians ranged from 0.82 (T-DXd steady-state minimum concentration) to 1.18 (DXd steady-state maximum concentration). Exposure-efficacy simulations estimated a confirmed objective response rate of 28.6% (90% confidence interval, 20.8-38.4) in real-world Western patients versus 40.1% (90% confidence interval, 33.5-47.0) in patients from Japan, possibly because of checkpoint inhibitor use in 4% versus 30% of patients, respectively. Western patients had a higher estimated rate of serious adverse events than patients from Japan (42.2% vs 34.6%); however, the rate of interstitial lung disease was lower (less than 10%) in Western patients. Overall, T-DXd was predicted to have meaningful clinical activity and a manageable safety profile in Western patients with HER2-positive gastric cancer. Using RWE, bridging analysis supported US approval of T-DXd 6.4 mg/kg in advanced gastric cancer before a clinical trial was completed in Western patients.

Model-based meta-analysis of non-small cell lung cancer with standard of care PD-1 inhibitors and chemotherapy for early development decision making.

Single-arm cohorts/trials are often used in early phase oncology programs to support preliminary clinical activity assessments for investigational products, administered alone or in combination with standard of care (SOC) agents. Benchmarking clinical activity of those combinations against other treatments, including SOC, requires indirect comparisons against external trials, which presents challenges including cross-study differences in trial populations/other factors. To facilitate such nonrandomized comparisons, we developed a comprehensive model-based meta-analysis (MBMA) framework to quantitatively adjust for factors related to efficacy in metastatic non-small cell lung cancer (mNSCLC). Data were derived from 15 published studies assessing key programmed cell death protein-1 (PD-1) inhibitors pembrolizumab (n = 8) and nivolumab (n = 7), representing current SOC in mNSCLC. In the first stage, a mixed-effects logistic regression model for overall response rate (ORR) was developed accounting for effects of various population covariates on ORR. The ORR model results indicated an odds ratio (OR) of 1.02 for squamous versus non-squamous histology and OR of 1.20 for PD-ligand 1 tumor proportion score (TPS) per every 10% increase of TPS level. Next, a nonparametric mixed-effects model for overall survival (OS) was developed with ORR/other clinical covariates as input. Subsequently, MBMA simulations of relevant hypothetical scenarios involving single-arm trial design predicted OS hazard ratios as a function of ORR with matched patient characteristics. Findings from this MBMA and derived parameter estimates can be generally applied by the reader as a framework for interpreting efficacy data from early phase trials to support ORR-based go/no-go decisions and futility rules, illustrated through examples in this report.

Exposure-Response Relationships in Patients With HER2-Positive Metastatic Breast Cancer and Other Solid Tumors Treated With Trastuzumab Deruxtecan.

Trastuzumab deruxtecan (T-DXd) is a HER2-targeting antibody-drug conjugate composed of a novel enzyme-cleavable linker and membrane-permeable topoisomerase I inhibitor payload. T-DXd has been approved for HER2-positive metastatic breast cancer and for HER2-positive metastatic gastric cancer. The approval in breast cancer was based on results from the DESTINY-Breast01 (U201; NCT03248492) and J101 (NCT02564900) trials. Here, we present dose justification for the approved 5.4 mg/kg every-3-weeks (Q3W) dose based on exposure-efficacy evaluated in patients with HER2-positive breast cancer (N = 337) from these 2 trials. Exposure-safety was assessed in patients with all tumor types (N = 639, n = 512 with breast cancer) across 5 trials, including J101 and DESTINY-Breast01. T-DXd doses ranged from 0.8-8.0 mg/kg Q3W; most patients received 5.4 (n = 312) or 6.4 mg/kg (n = 291). For each end point, multivariate logistic or Cox regression analysis was performed using various exposure metrics of T-DXd and released drug. A statistically significant association was observed between intact T-DXd area under the concentration-time curve (AUC) and confirmed objective response rate (ORR; P = 0.028). No significant exposure-response relationships were observed between intact T-DXd or released drug and duration of response or progression-free survival; however, follow-up was limited. All evaluated safety end points demonstrated a significant (P < 0.05) relationship with either intact T-DXd or released drug, with higher adverse event (AE) rates projected at higher exposures. Dose-response projections suggested an increase in ORR (67.5% vs. 62.9%) and toxicity (e.g., grade ≥ 3 all-cause treatment-emergent AEs: 61% vs. 54%) with T-DXd 6.4 vs. 5.4 mg/kg. Results demonstrate the benefit-risk profile at different doses and guide clinicians in the use of the 5.4-mg/kg Q3W dose in patients with HER2-positive metastatic breast cancer.

Selinexor population pharmacokinetic and exposure-response analyses to support dose optimization in patients with diffuse large B-cell lymphoma.

PURPOSE: Characterize the population PK and exposure-response (ER) relationships of selinexor in patients with diffuse large B-cell lymphoma (DLBCL) (efficacy endpoints) or other non-Hodgkin's lymphoma (NHL) patients (safety endpoints) to determine the optimal dose in patients with DLBCL. METHODS: This work included patients from seven clinical studies, with 800 patients for PK, 175 patients for efficacy and 322 patients for safety analyses. Logistic regression models and Cox-regression models were used for binary and time-to-event endpoints, respectively. Model-based simulations were performed to justify dose based on balance between efficacy and safety outcome. RESULTS: Selinexor pharmacokinetics were well-described by a two-compartment model with body weight as a significant covariate on clearance and central volume of distribution and gender on clearance. Overall response rate (ORR) in patients with DLBCL increased with day 1 Cmax and decreased in patients with higher baseline tumor size (p < 0.05). Significant exposure-safety relationships (p < 0.05) in NHL patients were identified for the frequency of the following safety endpoints: dose modifications, decreased appetite Grade ≥ 3 (Gr3+), fatigue Gr2+, vision blurred Gr1+, and vomiting Gr2+. Similar exposure-safety relationships were found for time-to-onset of the adverse events. CONCLUSIONS: Simulations of the safety and efficacy ER models suggested that, compared to a starting dose of 60 mg twice weekly (BIW), a 40 mg BIW regimen resulted in an absolute decrease in AE probabilities between 1.9 and 5.3%, with a clinically significant absolute efficacy decrease of 4.7% in ORR. The modeling results support that 60 mg BIW is the optimal dose in patients with DLBCL.

Population pharmacokinetic and exposure-response analyses of ivosidenib in patients with IDH1-mutant advanced hematologic malignancies.

Ivosidenib is a once daily (q.d.), orally available, potent mutant isocitrate dehydrogenase 1 (mIDH1) inhibitor approved for treatment of patients with relapsed or refractory (R/R) acute myeloid leukemia (AML) and intensive chemotherapy ineligible AML with a susceptible IDH1 mutation. Population pharmacokinetics (PKs; N = 253), exposure-response (efficacy [n = 201] and safety [n = 253]), and concentration-corrected electrocardiogram QT interval (QTc; n = 171) analyses were performed using phase I data (100 mg twice daily and 300-1200 mg q.d.). Ivosidenib disposition was well-described by a two-compartment PK model with first-order absorption and elimination. Between-subject variability was moderate for PK parameters. Intrinsic factors did not affect ivosidenib PKs. Moderate/strong CYP3A4 inhibitors increased the area under the plasma ivosidenib concentration-time curve at steady state (AUCss ) by 60%. Efficacy responders and nonresponders had similar ivosidenib exposures. Based on AUCss , there was no apparent relationship between ivosidenib exposure and efficacy or adverse events. The plasma ivosidenib concentration-QT analysis showed a mean change in QTc using Fridericia's method (ΔQTcF) of 17.2 msec at the approved 500 mg q.d. dose. Because of the direct association between ivosidenib exposure and QTcF, patients should have their electrocardiograms and electrolytes monitored, and comedications that increase ivosidenib exposure or prolong the QT interval should be avoided. These model-based analyses quantitatively provide a framework to describe the relationship among ivosidenib dose, exposure, and clinical end points. With precautions for QTc prolongation, the exposure-response analyses support the 500 mg q.d. dose in patients with AML with a susceptible IDH1 mutation.

Population Pharmacokinetics of Trastuzumab Deruxtecan in Patients With HER2-Positive Breast Cancer and Other Solid Tumors.

Trastuzumab deruxtecan (DS-8201) is a human epidermal growth factor receptor 2 (HER2)-targeting antibody-drug conjugate with a novel enzyme-cleavable linker, a topoisomerase I inhibitor payload, and a drug-to-antibody ratio of ≈ 8. We have characterized the population pharmacokinetics (PK) of trastuzumab deruxtecan and released drug (topoisomerase I inhibitor) in patients with HER2-positive breast cancer or other solid tumor malignancies. This analysis includes pooled data from five clinical studies with 639 patients. Trastuzumab deruxtecan doses ranged from 0.8 to 8.0 mg/kg every 3 weeks. Serum concentrations of trastuzumab deruxtecan and released drug were analyzed using a sequential two-step approach, with the nonlinear mixed-effects modeling methods. Covariate assessment was based upon stepwise forward-addition and backward-elimination process, followed by both univariate and multivariate analysis quantifying their impact on steady-state exposure of trastuzumab deruxtecan and released drug. A two-compartment model with linear elimination best described PK profiles of intact trastuzumab deruxtecan, while a one-compartment model with time-varying release-rate constant and linear elimination described released-drug PK profiles. Statistically significant covariates (country, tumor size, sex, formulation, age, body weight, albumin, total bilirubin, and aspartate aminotransferase) resulted in < 20% change in steady-state area under the concentration-time curve of trastuzumab deruxtecan and released drug, except for increased body weight (95th percentile, 86 kg) and decreased albumin (5th percentile, 31 g/L). Analysis of patients stratified by country, race, renal function, and hepatic function found no clinically meaningful differences in steady-state exposure of intact trastuzumab deruxtecan or released drug. Overall, results suggest that no dose adjustment based on tested covariates or in specific patient populations is warranted.

Population pharmacokinetics, exposure-safety, and immunogenicity of atezolizumab in pediatric and young adult patients with cancer.

BACKGROUND: The iMATRIX-atezolizumab study was a phase I/II, multicenter, open-label study designed to assess the safety and pharmacokinetics of atezolizumab in pediatric and young adult patients. We describe the pharmacokinetics (PK), exposure-safety, and immunogenicity of atezolizumab in pediatric and young adults with metastatic solid tumors or hematologic malignancies enrolled in this study. METHODS: Patients aged < 18 years (n = 69) received a weight-adjusted dose of atezolizumab (15 mg/kg every 3 weeks [q3w]; maximum 1200 mg); those aged ≥ 18 years (n = 18) received a flat dose (1200 mg q3w). A prior two-compartment intravenous infusion input adult population-PK (popPK) model of atezolizumab was used as a basis to model pediatric data. RESULTS: A total of 431 atezolizumab serum concentrations from 87 relapse-refractory pediatric and young adult patients enrolled in the iMATRIX-atezolizumab study were used for the popPK analysis. The dataset comprised predominantly patients aged < 18 years, including two infants aged < 2 years, with a wide body weight and age range. The clearance and volume of distribution estimates of atezolizumab were 0.217 L/day and 3.01 L, respectively. Atezolizumab geometric mean trough exposures were ~ 20% lower in pediatric patients versus young adults; this was not clinically meaningful as both groups achieved the target concentration (6 µg/mL). Safety was similar between pediatric and young adult patients with no exposure-safety relationship observed. Limited responses (4/87) precluded an exposure-response assessment on outcomes. A comparable rate (13% vs 11%) of atezolizumab anti-drug antibodies was seen in pediatric and young adult patients. CONCLUSIONS: These findings demonstrate a similar exposure-safety profile of atezolizumab in pediatric and young adult patients, supportive of weight-based dosing in pediatric patients. TRIAL REGISTRATION: NCT02541604.

Exposure-Response-Based Product Profile-Driven Clinical Utility Index for Ipatasertib Dose Selection in Prostate Cancer.

The aims of this work were to characterize ipatasertib exposure-response (E-R) relationships in a phase II study and to quantitatively assess benefit-risk using a clinical utility index approach to support ipatasertib phase III dose selection in patients with metastatic castration-resistant prostate cancer. Logistic regression and Cox proportional-hazards models characterized E-R relationships for safety and efficacy endpoints, respectively. Exposure metrics with and without considering dose interruptions/reductions (modifications) were tested in the E-R models. Despite a steeper E-R relationship when accounting for dose modifications, similar dose-response projections were generated. The clinical utility index analysis assessed important attributes, weights, and clinically meaningful cutoff/tradeoff values based on predefined minimal, target, and optimistic product profiles. Ipatasertib 400 mg daily, showing the highest probability of achieving the minimal product profiles and better benefit-risk balance than other doses (200-500 mg daily), was selected for further development in metastatic castration-resistant prostate cancer.

Development of a Subcutaneous Fixed-Dose Combination of Pertuzumab and Trastuzumab: Results From the Phase Ib Dose-Finding Study.

Adding pertuzumab to trastuzumab (both monoclonal antibodies targeting human epidermal growth factor receptor 2 [HER2]) has proven survival benefits when combined with chemotherapy for patients with HER2-positive breast cancer. The combination of pertuzumab and trastuzumab together in 1 vial for subcutaneous (SC) administration is being developed as a ready-to-use formulation to reduce the treatment burden on patients while improving healthcare efficiency. An open-label, 2-part, phase Ib dose-finding study (NCT02738970) was undertaken in healthy male volunteers (part 1) and female patients with HER2-postive early breast cancer who had completed standard (neo)adjuvant treatment (part 2). This study aimed to identify an SC pertuzumab dose given with recombinant human hyaluronidase that results in comparable exposure to that of the intravenous (IV) pertuzumab dose, based on pertuzumab serum trough concentration and area under the serum concentration-time curve. Pharmacokinetics (PK), safety, and tolerability of a single dose of SC pertuzumab given alone or in a fixed-dose combination (comixed or coformulated) with trastuzumab were also assessed. A maintenance dose of 600 mg for SC pertuzumab resulted in an equivalent exposure to that of IV pertuzumab, and no new safety signals were identified for SC pertuzumab or trastuzumab. A loading dose of 1200 mg for SC pertuzumab was selected based on approximate dose proportionality. The PK and safety results support further development of a fixed-dose coformulation combination of pertuzumab and trastuzumab for SC administration, which will be investigated in an upcoming phase III trial in patients with HER2-positive early breast cancer.

Meta-analysis of published efficacy and safety data for docetaxel in second-line treatment of patients with advanced non-small-cell lung cancer.

PURPOSE: To gain a better understanding of the impact of dose and other prognostic factors on safety and efficacy of docetaxel in second-line non-small-cell lung cancer patients. METHODS: A model-based meta-analysis (MBMA) of a published docetaxel monotherapy data in 6085 second-line non-small-cell lung cancer patients from 46 trials was conducted. RESULTS: The logit of grade 3/4 neutropenia incidence was a linear function of dose, with a 5% increase in the odds of neutropenia per mg/m(2) increase in dose [odds ratio (OR) 1.05, 95% confidence interval (CI) 1.04-1.06], and a Japanese study effect (OR 17.1, 95% CI 6.05-48.4). The logit of overall response rate (ORR) was a linear function of cumulative dose (0.4% increase in the odds of response per mg/m(2) increase; OR 1.004, 95% CI 1.001-1.008) and median population age (OR 1.08 per year, 95% CI 1.02-1.15). A Japanese study effect was identified for overall survival (OS) in addition to prognostic factors identified by a previous meta-analysis. CONCLUSIONS: This current MBMA identified docetaxel dose-response relationships for both neutropenia and ORR, an effect of age on ORR, and Japanese study effects on both neutropenia and OS.

Mechanistic pharmacokinetic/pharmacodynamic modeling of in vivo tumor uptake, catabolism, and tumor response of trastuzumab maytansinoid conjugates.

PURPOSE: Trastuzumab emtansine (T-DM1), an antibody-drug conjugate (ADC) comprised of trastuzumab linked to the antimitotic agent DM1, has shown promising results in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer. Investigations of the mechanisms of the action of ADCs, including T-DM1, have been primarily descriptive or semiquantitative. However, quantitative pharmacokinetic/pharmacodynamic (PK/PD) analysis may provide insights into their complex behavior. The analyses described herein applied PK/PD modeling to nonclinical studies of maytansinoid conjugates. METHODS: The maytansinoid conjugates T-DM1 and T-SPP-DM1, with thioether and disulfide linkers, respectively, were tested in mouse efficacy, PK, and tumor uptake studies. (3)[H]DM1-bearing ADCs were used to facilitate the quantitation of the ADCs in plasma, as well as ADC and ADC catabolites in tumors. Three mechanistic PK/PD models were used to characterize plasma ADC, tumor ADC, and tumor catabolite concentrations. Tumor catabolite concentrations were used to fit tumor response. Model parameters were estimated using R software and nonlinear least squares regression. RESULTS: Plasma ADC-associated DM1 concentrations of T-DM1 decreased more slowly than those of T-SPP-DM1, likely due to slower DM1 release. A comparison of the mechanistic models found that the best model allowed catabolism and catabolite exit rates to differ between ADCs, that T-DM1 exhibited both faster tumor catabolism and catabolite exit rate from tumors than T-SPP-DM1; findings inconsistent with expected behavior based on the physicochemical nature of the respective catabolites. Tumor catabolite concentrations adequately described tumor response with both ADCs showing similar potency. CONCLUSION: Mechanistic PK/PD studies described herein provided results that confirmed and challenged current hypotheses, and suggested new areas of investigation.