Bioequivalence of 240 mg Apalutamide Tablets and Preparation in Aqueous Food Vehicles for Alternative Administration

A 240-mg single tablet has been developed with the focus of reducing the pill burden of the apalutamide daily dose of 240 mg (4 × 60-mg tablets). An open-label, randomized, single-dose phase 1 study with a 2-sequence and 2-period crossover design in healthy men determined the bioequivalence of a 240-mg single tablet versus the currently available 4 × 60-mg tablets (Part 1, N = 74) and assessed effect of a high-fat meal (Part 2, N = 21) on apalutamide maximum plasma concentration (Cmax) and the area under the plasma concentration-time curve (AUC0-72 h). The 90% confidence interval of geometric mean ratios for Cmax and AUC0-72 h fell between 80% and 125% for both Part 1 and Part 2. No new safety concerns with the 240-mg single tablet were observed. To support the use of different food vehicles as well as nasogastric (NG) tubes for alternative administration, we conducted in vitro compatibility studies to evaluate the purity, dose, and stability of 240-mg tablets dispersed in applesauce/yogurt/orange juice/green tea as well as in NG tubes (polyurethane/silicone/polyvinyl chloride). The studies confirmed the alternative administrations do not affect the purity, dose-accuracy, or stability of apalutamide. The apalutamide 240-mg tablet is bioequivalent to 4 × 60-mg tablets and compatible with the tested food vehicles and NG tubes.

Demonstrating Bioequivalence for Two Dose Strengths of Niraparib and Abiraterone Acetate Dual-Action Tablets Versus Single Agents: Utility of Clinical Study Data Supplemented with Modeling and Simulation

BACKGROUND AND OBJECTIVE

The combination of niraparib and abiraterone acetate (AA) plus prednisone is under investigation for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) and metastatic castration-sensitive prostate cancer (mCSPC). Regular-strength (RS) and lower-strength (LS) dual-action tablets (DATs), comprising niraparib 100 mg/AA 500 mg and niraparib 50 mg/AA 500 mg, respectively, were developed to reduce pill burden and improve patient experience. A bioequivalence (BE)/bioavailability (BA) study was conducted under modified fasting conditions in patients with mCRPC to support approval of the DATs.

METHODS

This open-label randomized BA/BE study (NCT04577833) was conducted at 14 sites in the USA and Europe. The study had a sequential design, including a 21-day screening phase, a pharmacokinetic (PK) assessment phase comprising three periods [namely (1) single-dose with up to 1-week run-in, (2) daily dose on days 1-11, and (3) daily dose on days 12-22], an extension where both niraparib and AA as single-agent combination (SAC; reference) or AA alone was continued from day 23 until discontinuation, and a 30-day follow-up phase. Patients were randomly assigned in a parallel-group design (four-sequence randomization) to receive a single oral dose of niraparib 100 mg/AA 1000 mg as a LS-DAT or SAC in period 1, and patients continued as randomized into a two-way crossover design during periods 2 and 3 where they received niraparib 200 mg/AA 1000 mg once daily as a RS-DAT or SAC. The design was powered on the basis of crossover assessment of RS-DAT versus SAC. During repeated dosing (periods 2 and 3, and extension phase), all patients also received prednisone/prednisolone 5 mg twice daily. Plasma samples were collected for measurement of niraparib and abiraterone plasma concentrations. Statistical assessment of the RS-DAT and LS-DAT versus SAC was performed on log-transformed pharmacokinetic parameters data from periods 2 and 3 (crossover) and from period 1 (parallel), respectively. Additional paired analyses and model-based bioequivalence assessments were conducted to evaluate the similarity between the LS-DAT and SAC.

RESULTS

For the RS-DAT versus SAC, the 90% confidence intervals (CI) of geometric mean ratios (GMR) for maximum concentration at a steady state (Cmax,ss) and area under the plasma concentration-time curve from 0-24 h at a steady state (AUC 0-24h,ss) were respectively 99.18-106.12% and 97.91-104.31% for niraparib and 87.59-106.69 and 86.91-100.23% for abiraterone. For the LS-DAT vs SAC, the 90% CI of GMR for AUC0-72h of niraparib was 80.31-101.12% in primary analysis, the 90% CI of GMR for Cmax,ss and AUC 0-24h,ss of abiraterone was 85.41-118.34% and 86.51-121.64% respectively, and 96.4% of simulated LS-DAT versus SAC BE trials met the BE criteria for both niraparib and abiraterone.

CONCLUSIONS

The RS-DAT met BE criteria (range 80%-125%) versus SAC based on 90% CI of GMR for Cmax,ss and AUC 0-24h,ss. The LS-DAT was considered BE to SAC on the basis of the niraparib component meeting the BE criteria in the primary analysis for AUC 0-72h; abiraterone meeting the BE criteria in additional paired analyses based on Cmax,ss and AUC 0-24h,ss; and the percentage of simulated LS-DAT versus SAC BE trials meeting the BE criteria for both.

CLINICALTRIALS

GOV IDENTIFIER

NCT04577833.

Determination and Confirmation of Recommended Ph2 Dose of Amivantamab in Epidermal Growth Factor Receptor Exon 20 Insertion Non-Small Cell Lung Cancer

Amivantamab has demonstrated durable responses with a tolerable safety profile in non-small cell lung cancer with EGFR exon 20 insertions (Ex20ins) who progressed after prior platinum chemotherapy. Data supporting the amivantamab recommended phase II dose (RP2D) in this patient population are presented. Pharmacokinetic (PK) analysis and population PK (PopPK) modeling were conducted using serum concentration data obtained following amivantamab intravenous administration (140-1,750 mg). Pharmacodynamics (PDs) were evaluated using depletion of soluble EGFR and MET. Exposure-response (E-R) analyses were performed using the primary efficacy end point of objective response rate in patients with EGFR Ex20ins. The E-R relationship for safety was explored for adverse events of clinical interest. Amivantamab exhibited linear PKs at 350-1,750 mg dose levels following administration, with no maximum tolerated dose identified. A two-compartment PopPK model with linear clearance adequately described the observed PKs. Body weight was a covariate of clearance and volume of distribution in the central compartment. PopPK modeling showed that a weight-based, 2-tier (< 80 and ≥ 80 kg) dosing strategy reduces PK variability and provides comparable exposure across 2 weight groups, with 87% of patients achieving exposures above the target threshold. The final confirmed RP2D of amivantamab was 1,050 mg for < 80 kg (1,400 mg for ≥ 80 kg) weekly in cycle 1 (28 days) and every 2 weeks thereafter. No significant exposure-efficacy or safety correlation was observed. In conclusion, the amivantamab RP2D is supported by PK, PD, safety, and efficacy analyses. E-R analyses confirmed that the current regimen provides durable efficacy with tolerable safety.

Cardiac Safety Assessment of Lazertinib: Findings From Patients With EGFR Mutation-Positive Advanced NSCLC and Preclinical Studies

Introduction

Lazertinib is a potent, irreversible, brain-penetrant, mutant-selective, and wild-type–sparing third-generation EGFR tyrosine kinase inhibitor (TKI), creating a wide therapeutic index. Cardiovascular adverse events (AEs), including QT prolongation, decreased left ventricular ejection fraction (LVEF), and heart failure, have emerged as potential AEs with certain EGFR TKI therapies.

Methods

Cardiac safety of lazertinib was evaluated in TKI-tolerant adults with EGFR mutation-positive locally advanced or metastatic NSCLC receiving lazertinib (20–320 mg/d). QT intervals corrected with Fridericia’s formula (QTcF) prolongation, time-matched concentration-QTcF relationship, change of LVEF, and cardiac failure-associated AEs were evaluated. The clinical findings were supplemented by the following three preclinical studies: an in vitro hERG inhibition assay, an ex vivo isolated perfused rabbit heart study, and an in vivo telemetry-instrumented beagle dog study.

Results

Preclinical evaluation revealed little to no physiological effect on the basis of electrocardiogram, electrophysiological, proarrhythmic, and hemodynamic parameters. Clinical evaluation of 181 patients revealed no clinically relevant QTcF prolongation by centralized electrocardiogram in any patient and at any dose level. The predicted magnitude of QTcF value increase at maximum steady-state plasma concentration for the therapeutic dose of lazertinib (240 mg/d) was 2.2 msec (upper bound of the two-sided 90% confidence interval: 3.6 msec). No patient had clinically relevant LVEF decrease (i.e., minimum postbaseline LVEF value of <50% and a maximum decrease in LVEF value from baseline of ≥10 percentage points). Cardiac failure-associated AE occurred in one patient (grade 2 decreased LVEF) and resolved without any dose modifications.

Conclusions

Our first-in-human study, together with preclinical data, indicates that lazertinib is not associated with increased cardiac risk.

Amivantamab in EGFR Exon 20 Insertion-Mutated Non-Small-Cell Lung Cancer Progressing on Platinum Chemotherapy: Initial Results From the CHRYSALIS Phase I Study

PURPOSE

Non–small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) exon 20 insertion (Exon20ins) mutations exhibits inherent resistance to approved tyrosine kinase inhibitors. Amivantamab, an EGFR-MET bispecific antibody with immune cell–directing activity, binds to each receptor's extracellular domain, bypassing resistance at the tyrosine kinase inhibitor binding site.

METHODS

CHRYSALIS is a phase I, open-label, dose-escalation, and dose-expansion study, which included a population with EGFR Exon20ins NSCLC. The primary end points were dose-limiting toxicity and overall response rate. We report findings from the postplatinum EGFR Exon20ins NSCLC population treated at the recommended phase II dose of 1,050 mg amivantamab (1,400 mg, ≥ 80 kg) given once weekly for the first 4 weeks and then once every 2 weeks starting at week 5.

RESULTS

In the efficacy population (n = 81), the median age was 62 years (range, 42-84 years); 40 patients (49%) were Asian, and the median number of previous lines of therapy was two (range, 1-7). The overall response rate was 40% (95% CI, 29 to 51), including three complete responses, with a median duration of response of 11.1 months (95% CI, 6.9 to not reached). The median progression-free survival was 8.3 months (95% CI, 6.5 to 10.9). In the safety population (n = 114), the most common adverse events were rash in 98 patients (86%), infusion-related reactions in 75 (66%), and paronychia in 51 (45%). The most common grade 3-4 adverse events were hypokalemia in six patients (5%) and rash, pulmonary embolism, diarrhea, and neutropenia in four (4%) each. Treatment-related dose reductions and discontinuations were reported in 13% and 4% of patients, respectively.

CONCLUSION

Amivantamab, via its novel mechanism of action, yielded robust and durable responses with tolerable safety in patients with EGFR Exon20ins mutations after progression on platinum-based chemotherapy.

Subcutaneous delivery of amivantamab in patients with advanced solid malignancies: PALOMA, an open-label, multicenter, dose escalation phase 1b study

TPS3150

Background: Amivantamab, an epidermal growth factor receptor (EGFR)-MET bispecific antibody with immune cell-directing activity, targets activating/resistance EGFR mutations and MET mutations/amplifications. Amivantamab has demonstrated antitumor activity in patients (pts) with EGFR-mutant NSCLC and also in pts with EGFR tyrosine kinase inhibitor-resistant disease. The recommended phase 2 dose (RP2D) is 1050 mg (1400 mg, ≥80 kg) administered as intravenous (IV) infusions weekly (QW) for the first 28-day cycle and every other week (Q2W) thereafter. A subcutaneous (SC) formulation of amivantamab has the potential to reduce pt and physician burden by reducing administration time. The safety and pharmacokinetics (PK) of amivantamab administered SC ± recombinant human hyaluronidase (rHuPH20) will be evaluated. Methods: PALOMA is an ongoing phase 1b dose escalation study of amivantamab SC in pts with advanced solid tumors that may derive benefit from EGFR or MET-directed therapy (NCT04606381). Pts must have progressed on standard of care therapy for metastatic disease, be ineligible for, or have refused current standard therapies. The primary endpoints are trough concentration at the end of QW dosing and safety of SC administration. The objective of part 1 is to evaluate the feasibility, safety, and PK of SC administration of a low concentration (50 mg/mL) formulation of amivantamab alone (Ami-LC) or admixed with rHuPH20 (Ami-LC-MD). Approximately 8 pts will be enrolled to receive either 1050/1400 mg amivantamab SC using Ami-LC-MD (Cohort 1a) or Ami-LC (Cohort 1b) QW in cycle 1 and Q2W thereafter. The objective of part 2 is to evaluate the safety and PK of SC administration of a high concentration (160 mg/mL) formulation of amivantamab alone (Ami-HC) or with rHuPH20 (Ami-HC-CF) and to determine a dose, schedule, and formulation for SC administration that achieves similar exposure as observed at the RP2D of amivantamab IV, with acceptable safety. Pts enrolled in part 2 will initially receive 1050/1400 mg amivantamab SC using Ami-HC-CF in Cohort 2a or Ami-HC in Cohort 2b. ≤10 pts may be enrolled in either cohort. Additional cohorts of ≤10 pts may be enrolled to support dose, schedule, and formulation selection as guided by safety and PK observations in earlier cohorts. To mitigate infusion related reactions (IRR), medication with steroid, paracetamol, and antihistamine will be given pre-infusion and as clinically indicated post-infusion. Safety assessments include monitoring adverse events, laboratory abnormalities, vital signs, IRR, and injection site reactions. Blood samples will be collected to assess PK, pharmacodynamics, and immunogenicity. A Study Evaluation Team composed of investigators and sponsor representatives will review safety and PK data to make decisions about dose escalation and cohort expansion throughout the conduct of the study. Clinical trial information: NCT04606381.

Optimization of clinical dosing schedule to manage neutropenia: learnings from semi-mechanistic modeling simulation approach

Neutropenia is a common side-effect of oncology drugs. We aimed to study the impact of exposure and dosing schedule on neutropenia to guide selection of dosing schedules that minimize neutropenia potential while maintaining the desired minimum concentration (C_min) required for target engagement. Dose, frequency and PK parameters were chosen for five hypothetical drugs of various half-lives to (1) achieve same exposure with continuous dosing and evaluate impact of 4 intermittent dosing schedules; and (2) achieve same nadir for continuous and intermittent dosing and evaluate impact on % time above C_min, a surrogate assumed to indicate target engagement. Absolute neutrophil count (ANC) profiles were simulated using Friberg model, a widely used semi-mechanistic myelosuppression model, assuming drug concentration directly reduce the proliferation rate of stem cells and progenitor cells in proliferation compartment. The correlations between different PK measures and neutropenia metrics were explored. In (1), when the same daily dose was used, intermittent schedules offered better management of ANC nadir. The reduced average drug exposure with intermittent dosing led to lower% time above C_min. In (2), when the dose was adjusted to achieve the same nadir, drugs with moderate half-life (8-48 h) showed similar % time above C_min regardless of schedule, while continuous dosing was better for a short half-life (4 h). Area under the concentration curve (AUC) was highly correlated with neutropenia. In summary, continuous dosing, with the dose selected correctly, is most effective to maintain % time above C_min while providing similar tolerability as intermittent dosing with a higher dose. But dose interruptions could be required to manage individual toxicities. Intermittent schedules, on the other hand, allow recovery of ANC, enabling more orderly schedules.

Abstract 3905: Translational efficacy and safety modeling and simulation to support the clinical development of JNJ-64619178, a PRMT5 inhibitor

Protein arginine methyltransferase 5 (PRMT5) is an epigenetic enzyme with oncogenic properties. JNJ-64619178 (JNJ178) is a potent, selective, structurally unique PRMT5 inhibitor with good preclinical efficacy in inhibiting the growth of hematologic and solid tumor cell lines. Toxicology studies showed that JNJ178 decreased reticulocytes and neutrophils in rats and dogs. The objectives of translational modeling and simulation were to understand the exposure-response relationship of both safety and efficacy and provide guidance to the first-in-human clinical development of JNJ178.

Experimental data for the PK/PD (Pharmacokinetics/Pharmacodynamics) modeling included: plasma concentration after single dose of JNJ178 in non-tumor bearing mice, plasma concentration and PD markers of dimethylation of arginine (%SDMA in plasma and %SMD1/3-Me2 in tumor, respectively) after multiple doses (1 to 10 mg/kg) QD (once daily) of JNJ178 in H1048 (human small cell lung carcinoma) xenografts, and tumor volume in four xenograft mouse models (A427, human lung carcinoma; H441, human lung adenocarcinoma; H520, human squamous cell lung carcinoma; and H1048). Plasma PK were first described by a standard two-compartment model and used as a driver of PD and tumor volume (efficacy). Plasma and tumor PD were modeled using an indirect response model. A hybrid tumor growth coupled with transit compartment mediated tumor killing model was used to fit the tumor volume data. To predict the safety profile of JNJ178, lifespan based indirect response model for erythropoiesis and Friberg myelosuppression model were used to simulate hemoglobin and neutrophil kinetics in human.

The PK/PD model described the data well and validated the hypothesis that PD is driven by trough concentration. Based on the exposure-response relationship from the four xenograft models, the trough concentration needed to achieve tumor stasis for mouse was determined. In addition, the level of inhibition in tumor and plasma PD marker that was associated with tumor stasis was identified. Together with human PK parameters scaled using allometry, the dose range needed to achieve target therapeutic exposure for a typical human subject was predicted. Simulation results from erythropoiesis and Friberg myelosuppression models informed the optimal doing schedules for certain dose levels that would allow hematological toxicity to be manageable with &lt;40% reduction in hemoglobin and &gt;1.0 x 109/L neutrophil counts at all times. Overall, a translational modeling and simulation approach that considers safety and efficacy has been instrumental in the design of the first-in-human clinical development of PRMT5 inhibitor JNJ178 regarding selection of dose and schedule.

Citation Format: Yue Guo, Nahor Haddish-Berhane, Hillary J. Millar, Tinne Verhulst, Tony Greway, Junguo Zhou, Loeckie DeZwart, Dana Gaffney, Joseph Portale, Dirk Brehmer, An Boeckx, Erika Van Heerde, Daniele Ouellet. Translational efficacy and safety modeling and simulation to support the clinical development of JNJ-64619178, a PRMT5 inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3905.

Correction to: A Translational Quantitative Systems Pharmacology Model for CD3 Bispecific Molecules: Application to Quantify T Cell-Mediated Tumor Cell Killing by P-Cadherin LP DART®

Typesetting error occurred and Figure 1a and Figure 1b were altered during the uploading process. The original article has been corrected.

A Translational Quantitative Systems Pharmacology Model for CD3 Bispecific Molecules: Application to Quantify T Cell-Mediated Tumor Cell Killing by P-Cadherin LP DART®

CD3 bispecific antibody constructs recruit cytolytic T cells to kill tumor cells, offering a potent approach to treat cancer. T cell activation is driven by the formation of a trimolecular complex (trimer) between drugs, T cells, and tumor cells, mimicking an immune synapse. A translational quantitative systems pharmacology (QSP) model is proposed for CD3 bispecific molecules capable of predicting trimer concentration and linking it to tumor cell killing. The model was used to quantify the pharmacokinetic (PK)/pharmacodynamic (PD) relationship of a CD3 bispecific targeting P-cadherin (PF-06671008). It describes the disposition of PF-06671008 in the central compartment and tumor in mouse xenograft models, including binding to target and T cells in the tumor to form the trimer. The model incorporates T cell distribution to the tumor, proliferation, and contraction. PK/PD parameters were estimated for PF-06671008 and a tumor stasis concentration (TSC) was calculated as an estimate of minimum efficacious trimer concentration. TSC values ranged from 0.0092 to 0.064 pM across mouse tumor models. The model was translated to the clinic and used to predict the disposition of PF-06671008 in patients, including the impact of binding to soluble P-cadherin. The predicted terminal half-life of PF-06671008 in the clinic was approximately 1 day, and P-cadherin expression and number of T cells in the tumor were shown to be sensitive parameters impacting clinical efficacy. A translational QSP model is presented for CD3 bispecific molecules, which integrates in silico, in vitro and in vivo data in a mechanistic framework, to quantify and predict efficacy across species.

JNJ-61186372 (JNJ-372), an EGFR-cMet bispecific antibody, in EGFR-driven advanced non-small cell lung cancer (NSCLC)

9009

Background: JNJ-372 binds EGFR and cMet to block ligand binding, promote receptor degradation, and trigger antibody-dependent cellular cytotoxicity in models of EGFR-mutated (EGFRm) NSCLC. Here we describe the ongoing phase 1 safety, pharmacokinetics (PK), and activity of JNJ-372 in patients (pts) with NSCLC, including 3rd generation tyrosine kinase inhibitor (3GTKI)-relapsed EGFRm NSCLC and EGFR Exon20ins disease. Methods: Pts received JNJ-372 (140–1400 mg) IV weekly for the first 28-day cycle and biweekly thereafter. 1050–1400 mg doses are being explored in dose expansion. Blood samples were collected for PK analyses. Efficacy by investigator per RECIST v1.1 in pts with EGFRm NSCLC treated at ≥700 mg is presented. Tumors were characterized by next-generation sequencing of circulating tumor (ct)DNA and/or tumor tissue. Results: As of 17 Jan 2019, 116 enrolled pts with NSCLC were treated. Median age was 63 years, 38% were male, 77% were Asian, and 97% had EGFR mutations. Mean duration of treatment was 3.8 months, longest exposure was 20 cycles. The PK data set included pts from Korea (77%) and the US (23%). At the 1050 mg dose, 72% of pts achieved average concentrations above the EC90 based on preclinical models. Adverse events (AEs; ≥20%) were rash (59%), infusion related reaction (58%), paronychia (28%), and constipation (22%). Additional EGFR/cMet-related AEs include stomatitis (17%), pruritis (15%), peripheral edema (11%), and diarrhea (7%). Grade ≥3 AEs were reported in 34% (8% treatment-related) with dyspnea (6%) and pneumonia (3%) most frequently observed. Among response-evaluable pts, 25/88 (28%) achieved best timepoint response of partial response (PR). 10/47 pts with prior 3GTKI therapy had best timepoint response of PR (6 confirmed), including 4 with C797S, 1 with cMet amplification, and 5 without identifiable EGFR/cMet-dependent resistance. 6/20 pts with Exon20ins had best timepoint response of PR (3 confirmed). Conclusions: JNJ-372 has a manageable safety profile consistent with EGFR and cMet inhibition. Preliminary responses were achieved in 3GTKI-relapsed disease, including C797S and cMet amplification, and Exon20ins disease; enrollment in dose expansion is ongoing. Clinical trial information: NCT02609776.

A CD3-bispecific molecule targeting P-cadherin demonstrates T cell-mediated regression of established solid tumors in mice

Strong evidence exists supporting the important role T cells play in the immune response against tumors. Still, the ability to initiate tumor-specific immune responses remains a challenge. Recent clinical trials suggest that bispecific antibody-mediated retargeted T cells are a promising therapeutic approach to eliminate hematopoietic tumors. However, this approach has not been validated in solid tumors. PF-06671008 is a dual-affinity retargeting (DART®)-bispecific protein engineered with enhanced pharmacokinetic properties to extend in vivo half-life, and designed to engage and activate endogenous polyclonal T cell populations via the CD3 complex in the presence of solid tumors expressing P-cadherin. This bispecific molecule elicited potent P-cadherin expression-dependent cytotoxic T cell activity across a range of tumor indications in vitro, and in vivo in tumor-bearing mice. Regression of established tumors in vivo was observed in both cell line and patient-derived xenograft models engrafted with circulating human T lymphocytes. Measurement of in vivo pharmacodynamic markers demonstrates PF-06671008-mediated T cell activation, infiltration and killing as the mechanism of tumor inhibition.

Preclinical to Clinical Translation of Antibody-Drug Conjugates Using PK/PD Modeling: a Retrospective Analysis of Inotuzumab Ozogamicin

A mechanism-based pharmacokinetic/pharmacodynamic (PK/PD) model was used for preclinical to clinical translation of inotuzumab ozogamicin, a CD22-targeting antibody-drug conjugate (ADC) for B cell malignancies including non-Hodgkin's lymphoma (NHL) and acute lymphocytic leukemia (ALL). Preclinical data was integrated in a PK/PD model which included (1) a plasma PK model characterizing disposition and clearance of inotuzumab ozogamicin and its released payload N-Ac-γ-calicheamicin DMH, (2) a tumor disposition model describing ADC diffusion into the tumor extracellular environment, (3) a cellular model describing inotuzumab ozogamicin binding to CD22, internalization, intracellular N-Ac-γ-calicheamicin DMH release, binding to DNA, or efflux from the tumor cell, and (4) tumor growth and inhibition in mouse xenograft models. The preclinical model was translated to the clinic by incorporating human PK for inotuzumab ozogamicin and clinically relevant tumor volumes, tumor growth rates, and values for CD22 expression in the relevant patient populations. The resulting stochastic models predicted progression-free survival (PFS) rates for inotuzumab ozogamicin in patients comparable to the observed clinical results. The model suggested that a fractionated dosing regimen is superior to a conventional dosing regimen for ALL but not for NHL. Simulations indicated that tumor growth is a highly sensitive parameter and predictive of successful outcome. Inotuzumab ozogamicin PK and N-Ac-γ-calicheamicin DMH efflux are also sensitive parameters and would be considered more useful predictors of outcome than CD22 receptor expression. In summary, a multiscale, mechanism-based model has been developed for inotuzumab ozogamicin, which can integrate preclinical biomeasures and PK/PD data to predict clinical response.

Abstract 5111: Bio-distribution and tumor targeting of a P-cadherin x CD3 bi-specific redirected T-cell molecule using fluorescence molecular tomography imaging

Introduction: Previously we have shown the utility of Fluorescent Molecular Tomography (FMT) imaging in evaluating bio-distribution of biologics. P-cadherin LP-DART is a bi-specific Dual Affinity Re-Targeting (DART®) molecule targeting CD3 expressed on T-cells and P-cadherin expressed on tumors. In this study we evaluated the bio-distribution and tumor targeting of P-cadherin LP-DART using FMT imaging in a colorectal xenograft model.

Methods: NSG or athymic nude mice with subcutaneous HCT-116 xenografts were used. Studies that included engraftment of T-cells received either PBMNCs or T-cells isolated from healthy human volunteers. Bio-distribution studies were initiated when the tumors reached 300-500 mm3. P-cadherin LP-DART or a negative control-DART (non-targeted domain x CD3 binding domain) was conjugated with a near-infrared fluorophore VivoTag680XL (VT680), and the labeling efficiency was determined by spectrophotometer. T-cells used in trafficking studies were labeled with CellVue815. Cell surface P-cadherin expression and P-cadherin LP-DART binding was determined by flow cytometry. T-cell activity was measured with cytotoxic T-lymphocyte (CTL) assays. FMT imaging was performed longitudinally post injection of labeled bi-specifics. Data was analyzed using TrueQuant software. Plasma and tissues were collected for PK analysis by ELISA or histology.

Results: VT680 conjugation to P-cadherin LP-DART did not significantly affect the binding to P-cadherin, whereas CD3 binding was decreased. In vivo FMT imaging revealed high levels of P-cadherin LP-DART accumulation in the tumors. The in vivo kinetics revealed that the peak accumulation in tumors was 96hrs post-injection. At 240hrs post-injection, there was still measurable P-cadherin LP-DART detected in tumors. Ex vivo imaging showed 20-25 fold increase in accumulation of P-cadherin LP-DART compared to negative control DART. Comparison of P-cadherin LP-DART accumulation between PBMNC engrafted and non-engrafted model showed no significant difference in quantity or kinetics. There was no significant difference in the kinetics of elimination in the whole-body, heart or liver between P-cadherin LP-DART or negative control. Ex vivo comparison of accumulation in various organs showed no difference between P-cadherin LP-DART or negative control. Cell trafficking studies with CellVue labeled T-cells showed the co-localization of T-cells and P-cadherin LP-DART in tumors.

Conclusion: FMT imaging showed that P-cadherin LP-DART specifically targeted HCT-116 tumors. Cell trafficking studies showed that engrafted T-cells accumulated in tumors. This study shows the utility of FMT in bio-distribution studies of biologics and in vivo cell trafficking.

Citation Format: Anand Giddabasappa, Vijay Gupta, Timothy S. Fisher, John David, Norberg Rand, Allison Rohner, Justin Cohen, Tracey Clark, Nahor Haddish-Berhane, Adam Root, Chad May. Bio-distribution and tumor targeting of a P-cadherin x CD3 bi-specific redirected T-cell molecule using fluorescence molecular tomography imaging. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5111. doi:10.1158/1538-7445.AM2015-5111

Antibody-drug conjugates: an emerging modality for the treatment of cancer

Antibody-drug conjugates (ADCs) offer promise as a therapeutic modality that can potentially reduce the toxicities and poor therapeutic indices caused by the lack of specificity of conventional anticancer therapies. ADCs combine the potency of cytotoxic agents with the target selectivity of antibodies by chemically linking a cytotoxic payload to an antibody, potentially creating a synthetic molecule that will deliver targeted antitumor therapy that is both safe and efficacious. The ADC repertoire contains a range of payload molecules, antibodies, and linkers. Two ADC molecules, Kadcyla® and Adcetris®, have been approved by the FDA, and many more are currently in clinical development.

A priori prediction of tumor payload concentrations: preclinical case study with an auristatin-based anti-5T4 antibody-drug conjugate

The objectives of this investigation were as follows: (a) to validate a mechanism-based pharmacokinetic (PK) model of ADC for its ability to a priori predict tumor concentrations of ADC and released payload, using anti-5T4 ADC A1mcMMAF, and (b) to analyze the PK model to find out main pathways and parameters model outputs are most sensitive to. Experiential data containing biomeasures, and plasma and tumor concentrations of ADC and payload, following A1mcMMAF administration in two different xenografts, were used to build and validate the model. The model performed reasonably well in terms of a priori predicting tumor exposure of total antibody, ADC, and released payload, and the exposure of released payload in plasma. Model predictions were within two fold of the observed exposures. Pathway analysis and local sensitivity analysis were conducted to investigate main pathways and set of parameters the model outputs are most sensitive to. It was discovered that payload dissociation from ADC and tumor size were important determinants of plasma and tumor payload exposure. It was also found that the sensitivity of the model output to certain parameters is dose-dependent, suggesting caution before generalizing the results from the sensitivity analysis. Model analysis also revealed the importance of understanding and quantifying the processes responsible for ADC and payload disposition within tumor cell, as tumor concentrations were sensitive to these parameters. Proposed ADC PK model provides a useful tool for a priori predicting tumor payload concentrations of novel ADCs preclinically, and possibly translating them to the clinic.

Abstract 4752: Preclinical development and translational research on a novel antibody-drug conjugate that targets 5T4, an oncofetal antigen expressed on tumor-initiating cells

Antibody-drug conjugates (ADCs) represent a promising therapeutic modality for the clinical management of cancer. We sought to develop a novel ADC that targets 5T4 (TPBG), an oncofetal antigen expressed on tumor-initiating cells (TICs), which comprise the most aggressive cell population in the tumor. We optimized an anti-5T4 ADC (A1mcMMAF) by sulfydryl-based conjugation of the humanized A1 antibody to the tubulin inhibitor monomethylauristatin F (MMAF) via a maleimidocaproyl linker. A1mcMMAF exhibited potent in vivo anti-tumor activity in a variety of tumor models and induced long-term regressions for up to 100 days after the last dose. Strikingly, animals showed pathological complete response in each model. In a non-small cell lung cancer patient-derived xenograft in which 5T4 is preferentially expressed on the less differentiated tumor cells, A1mcMMAF treatment resulted in sustained tumor regressions and reduced TIC frequency. These results highlight the potential of ADCs that target the most aggressive cell populations within tumors. An optimized pharmacokinetic/pharmacodynamic (PK/PD) model of tumor growth and drug kill was used to characterize the ADC concentration response relationship in mouse. A holistic secondary parameter, tumor static concentration (TSC), was derived from model parameters to quantify efficacy and support early clinical trial design. Tumor static concentrations [80% confidence] of A1mcMMAF ranged from 1.1[0.9 -1.4] μg/ml to 11.6 [9.6 - 14.1] μg/ml across tumor models. For comparison, in the clinic T-DM1 has an average concentration of 14 μg/ml at an efficacious dose of 3.6 mg/kg Q3wk (HER+ breast cancer) (Krop et al. 2010) and Brentuximab-vedotin has an average concentration of 3.65 μg/ml at an efficacious dose of 1.8 mg/kg Q 3wk (HL/ ALCL) (Younes et al. 2010). Taken together, the preclinical data established a promising therapeutic index that supports clinical testing of A1mcMMAF. Expression analysis profiling using clinical and preclinical data indicated that lung and breast tumors demonstrated differentially high expression of 5T4 in comparison to normal tissues. An IHC assay developed in house confirmed the hypothesis that a broad range of 5T4 expression was measurable in NSCLC patient tumor samples. Additionally, we developed an assay that measures 5T4 expression on circulating tumor cells (CTCs) and used this assay to measure and characterize a broad range of 5T4 expression in CTCs obtained from the blood of NSCLC patients. We intend to deploy these co-developed immunoassays to guide A1mcMMAF clinical development.

Citation Format: Puja Sapra, Marc Damelin, Kimberly Marquette, Kenneth G. Geles, Jonathon Golas, Maureen Dougher, Bitha Narayanan, Andreas Giannakou, Kiran Khandke, Russell Dushin, Elana Ernstoff, Judy Lucas, Mauricio Leal, George Hu, Alison Betts, Nahor Haddish-Berhane, Eric Powell, Steven Pirie-Shepherd, Christopher O'Donnell, Lioudmila Tchistiakova, Hans-Peter Gerber, Dena Marrinucci, Eric Tucker. Preclinical development and translational research on a novel antibody-drug conjugate that targets 5T4, an oncofetal antigen expressed on tumor-initiating cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4752. doi:10.1158/1538-7445.AM2013-4752

Pharmacodynamic model of sodium-glucose transporter 2 (SGLT2) inhibition: implications for quantitative translational pharmacology

Sodium-glucose co-transporter-2 (SGLT2) inhibitors are an emerging class of agents for use in the treatment of type 2 diabetes mellitus (T2DM). Inhibition of SGLT2 leads to improved glycemic control through increased urinary glucose excretion (UGE). In this study, a biologically based pharmacokinetic/pharmacodynamic (PK/PD) model of SGLT2 inhibitor-mediated UGE was developed. The derived model was used to characterize the acute PK/PD relationship of the SGLT2 inhibitor, dapagliflozin, in rats. The quantitative translational pharmacology of dapagliflozin was examined through both prospective simulation and direct modeling of mean literature data obtained for dapagliflozin in healthy subjects. Prospective simulations provided time courses of UGE that were of consistent shape to clinical observations, but were modestly biased toward under prediction. Direct modeling provided an improved characterization of the data and precise parameter estimates which were reasonably consistent with those predicted from preclinical data. Overall, these results indicate that the acute clinical pharmacology of SGLT2 inhibitors in healthy subjects can be reasonably well predicted from preclinical data through rational accounting of species differences in pharmacokinetics, physiology, and SGLT2 pharmacology. Because these data can be generated at the earliest stages of drug discovery, the proposed model is useful in the design and development of novel SGLT2 inhibitors. In addition, this model is expected to serve as a useful foundation for future efforts to understand and predict the effects of SGLT2 inhibition under chronic administration and in other patient populations.

SIMDOT-AbMe: microphysiologically based simulation tool for quantitative prediction of systemic and local bioavailability of targeted oral delivery formulations

The purpose of this study was to develop a physiologically based simulation tool that is able to predict local as well as systemic bioavailability of 5-aminosalicylic acid (5-ASA)-targeted delivery formulations using the existing understanding of the transport and metabolism mechanisms of 5-ASA. The model accounts for active and passive transcellular transport (absorptive and efflux), passive paracellular transport, intestinal biotransformation, and systemic metabolism and clearance. The intestinal physiology was represented by transverse segments for ileum and proximal colon and longitudinal compartments for the microphysiology of the intestinal tissue. The tool, equipped with an optimization routine that enables tuning model parameters, was developed in Matlab and uses a user-friendly graphical interface for data input and output. Physiologic and kinetic model parameters were estimated either from literature monolayer transport studies using nonlinear curve fitting or obtained directly from the literature. 5-ASA clinical pharmacokinetic profiles of a once-daily (one 4-g/day dose) and twice-daily (two 2-g/day doses) dosing regimen were used to partially calibrate and validate the model, respectively. Simulation results showed that drug C(max) in the gut mucosal layers reached a higher level and was achieved sooner than in the systemic blood level. The computed relative local bioavailability with respect to the systemic bioavailability was 0.063. With use of the model, the relative local bioavailability of different formulations can be established for fast performance verification of new preparations based on measured systemic bioavailability. These types of models play a critical role in designing such preparations and rapidly assessing their effectiveness and will foster efficient experimental designs, saving time and resources.

The role of multiscale computational approaches for rational design of conventional and nanoparticle oral drug delivery systems

Multiscale computational modeling of drug delivery systems (DDS) is poised to provide predictive capabilities for the rational design of targeted drug delivery systems, including multi-functional nanoparticles. Realistic, mechanistic models can provide a framework for understanding the fundamental physico-chemical interactions between drug, delivery system, and patient. Multiscale computational modeling, however, is in its infancy even for conventional drug delivery. The wide range of emerging nanotechnology systems for targeted delivery further increases the need for reliable in silico predictions. This review will present existing computational approaches at different scales in the design of traditional oral drug delivery systems. Subsequently, a multiscale framework for integrating continuum, stochastic, and computational chemistry models will be proposed and a case study will be presented for conventional DDS. The extension of this framework to emerging nanotechnology delivery systems will be discussed along with future directions. While oral delivery is the focus of the review, the outlined computational approaches can be applied to other drug delivery systems as well.

Biological Variability and Targeted Delivery of Therapeutics for Inflammatory Bowel Diseases: An In Silico Approach

Existing treatments of IBD adopt targeted oral drug delivery route for delivering bioactive agents more efficiently and with fewer side effects. However, the complex and dynamic luminal environment of the GIT and major intra/inter patient variability greatly affects treatment, resulting in variable clinical response in patients. Mathematical simulation model can be employed to consider the complex luminal environment to asses the performance of drug delivery systems for clinical efficacy. The objective of this paper was to evaluate existing targeted oral drug delivery system for the treatment of IBD subject to inter/intra patient luminal variability using in silico experiments employing previously developed mathematical model. Simulation results indicated that the average small intestinal drug release was 44+/-19% and 48+/-21% for healthy and UC subjects, respectively. The systemic absorption of drug approached 10-25% in healthy controls and 16-32% in UC subjects. Calculated drug release from the simulations for different scenario of pH and TT had a good agreement with the clinical in vivo data (13-36% and 17-35% for healthy and UC subjects, respectively). This agreement was also true for 5-ASA and its metabolite (N-acetyl-5-ASA) recovery in the colon. The computational model has a high degree of agreement with data obtained from literature. Physicians can use characteristic performance curves of different delivery systems produced in silico to select a delivery system that would work best for their patients based upon the patient's pH and transit time profiles. It also could be used by the pharmaceutical industry to improve their medicine efficacy by altering the design.

Modeling film-coat non-uniformity in polymer coated pellets: A stochastic approach

The objective of the present study is to include coating thickness non-uniformity in the development of a drug release model using coated ion-exchange pellets through the use of stochastic approaches. Drug release from ion-exchange resins was described using a Nernst-Plank model. Complexes of a model drug (dextromethorphan) and Dowex 50WX4-200 were prepared using a modified batch method and coated with Kollicoat SR 30D polymer. The deterministic model, validated using experimental drug release profiles for different coating thicknesses at 0%, 10%, 15%, 20% (w/w), was in agreement with the experimental data with a maximum root mean square error (RMSE) of 2.4%. An arbitrary Lagrangian-Eulerian approach was pursued to develop models of spherical pellets with non-uniform coating thicknesses. The Monte Carlo method was used to simulate the effect of the level of coating deformity on the cumulative drug release profile. Considering the co-existence of equal percentages of deformed and undeformed pellets in a batch, the cumulative release profile can vary by approximately +/-6% as a result of coating non-uniformity. The release profile obtained for a model of an arbitrary pellet with an actual non-uniform coating profile was in good agreement with the average release profile for the models of the theoretical randomly deformed pellets. The developed mathematical model is a useful tool to evaluate and predict release profiles of polymer coated ion-exchange resin complexes.

A multi-scale stochastic drug release model for polymer-coated targeted drug delivery systems

A multi-scale mathematical model for drug release of oral targeted drug delivery systems was developed and applied to a commercially available delayed release tablet (Asacol) that delivers 5-aminosalicyclic acid (5-ASA) to the colon. Underlying physical and biochemical principles governing the involved processes (diffusion and dissolution) were employed to develop the mathematical description. Finite element formulation was used to numerically solve the model equations. Molecular dynamics (MD) simulations were used to predict macro-scale transport properties of the drug and the biologic fluid. The effect of pH variability in the gastrointestinal tract environment on the dissolution of the polymeric enteric coating was investigated using the Monte Carlo method. The direct coupling method employed (MD) predicted a sufficiently accurate diffusion coefficient (5.7x10(-6) cm2 s-1) of the drug molecules in reasonable (3 h) computation times. The model was validated using experimental data from in vitro dissolution experiments and provided accurate prediction of the drug release from the delivery system (root mean square error of 5%). The amount of drug entering the systemic circulation, computed from the predicted drug release in varying pH environments in the small bowel, was 15-24%. This range was in good agreement with clinical in vivo data (13-36%) obtained from literature. This research shows that in silico experiments using mechanistic models and stochastic approaches can be used for drug design and optimization and as a decision making tool for physicians.