The HER2-directed antibody-drug conjugate DHES0815A in advanced and/or metastatic breast cancer: preclinical characterization and phase 1 trial results.

Approved antibody-drug conjugates (ADCs) for HER2-positive breast cancer include trastuzumab emtansine and trastuzumab deruxtecan. To develop a differentiated HER2 ADC, we chose an antibody that does not compete with trastuzumab or pertuzumab for binding, conjugated to a reduced potency PBD (pyrrolobenzodiazepine) dimer payload. PBDs are potent cytotoxic agents that alkylate and cross-link DNA. In our study, the PBD dimer is modified to alkylate, but not cross-link DNA. This HER2 ADC, DHES0815A, demonstrates in vivo efficacy in models of HER2-positive and HER2-low cancers and is well-tolerated in cynomolgus monkey safety studies. Mechanisms of action include induction of DNA damage and apoptosis, activity in non-dividing cells, and bystander activity. A dose-escalation study (ClinicalTrials.gov: NCT03451162) in patients with HER2-positive metastatic breast cancer, with the primary objective of evaluating the safety and tolerability of DHES0815A and secondary objectives of characterizing the pharmacokinetics, objective response rate, duration of response, and formation of anti-DHES0815A antibodies, is reported herein. Despite early signs of anti-tumor activity, patients at higher doses develop persistent, non-resolvable dermal, ocular, and pulmonary toxicities, which led to early termination of the phase 1 trial.

Pharmacokinetic and exploratory exposure-response analysis of pertuzumab in patients with operable HER2-positive early breast cancer in the APHINITY study.

PURPOSE: To characterize the pharmacokinetics (PK) of, and perform an exploratory exposure-response (E-R) analysis for, pertuzumab in patients with HER2-positive early breast cancer (EBC) within the APHINITY study (NCT01358877, BIG 4-11/BO25126/TOC4939G). METHODS: A previously developed pertuzumab two-compartment linear population pharmacokinetic (popPK) model was subjected to external validation to examine appropriateness for describing pertuzumab concentrations from the APHINITY study. Pharmacokinetic drug-drug interactions (DDIs) between pertuzumab, trastuzumab, and chemotherapy were assessed by comparing observed serum or plasma Cmax, Cmin, and AUClast geometric mean ratios with 90% CIs. Predictions of pertuzumab Cmax,ss, Cmin,ss, and AUCss were derived from individual parameter estimates and used in an exploratory E-R analysis. RESULTS: Using data from 72 patients, based on goodness-of-fit, the popPK model was deemed appropriate for predictions of individual exposures for subsequent comparisons to historical data, assessment of DDIs, and E-R analyses. No evidence of DDIs for pertuzumab on trastuzumab, trastuzumab on pertuzumab, or pertuzumab on chemotherapy PK was observed. Analyses of differences in exposure between patients with and without invasive disease-free survival events did not indicate improved efficacy with increased exposure. Overall Grade ≥ 3 diarrhea prevalence was higher with pertuzumab versus placebo, but was not greater with increasing pertuzumab exposure. No apparent E-R relationship was suggested with respect to other grade ≥ 3 AEs. CONCLUSION: Overall, the limited available data from this exploratory study suggest that no dose adjustments are needed for pertuzumab when administered in combination with trastuzumab and an EBC chemotherapy regimen.

Incidence of Gastrointestinal Perforations in Patients with Rheumatoid Arthritis Treated with Tocilizumab from Clinical Trial, Postmarketing, and Real-World Data Sources.

INTRODUCTION: The aim of this study was to use multiple data sources to update information on gastrointestinal perforations (GIPs) during tocilizumab (TCZ) treatment in patients with rheumatoid arthritis (RA). METHODS: Reporting rates of GIP events were estimated from three distinct patient data sets: a TCZ-IV RA clinical trial all-exposure population, a global TCZ postmarketing safety database population, and a US healthcare claims database population of patients with RA, including patients who received TCZ, anti-tumor necrosis factor (aTNF) agents, or abatacept. RESULTS: The clinical trial, global postmarketing, and healthcare claims populations provided 17,906, 382,621, and 3268 patient-years (PYs) of TCZ exposure, respectively. GIP incidence rates [95% confidence interval (CI)] were 1.9 (1.3-2.7), 1.2 (1.1-1.3), and 1.8 (0.7-4.0; specific definition) to 2.8 (1.3-5.2; sensitive definition) per 1000 PYs for the clinical trial, postmarketing, and healthcare claims populations, respectively. The GIP incidence rate (95% CI) for the comparator aTNF healthcare claims population ranged from 0.6 (0.3-1.2) to 0.9 (0.5-1.5) per 1000 PYs, for an absolute rate difference between TCZ and aTNFs of 1.2 (-0.3 to 2.5) to 1.9 (0.0-3.7) per 1000 PYs, corresponding to a number needed to harm between 533 and 828. CONCLUSION: The TCZ GIP event rates from multiple data sources were consistent with previously reported rates, did not increase over time, and were significantly associated with the number of prior biologics. Comparison of GIP incidence rates among patients with prior biologic exposure suggests that, for every 1000 patients treated with TCZ per year, an additional 1-2 GIP events might occur compared with patients treated with aTNFs. FUNDING: Roche.