GDC-0449, an orally active small molecule that targets the hedgehog pathway, appears to have antitumor activity in locally advanced or metastatic basal-cell carcinoma. (ClinicalTrials.gov number, NCT00607724.)

PurposeAn item response theory (IRT) pharmacometric framework is presented to characterize Functional Assessment of Cancer Therapy-Breast (FACT-B) data in locally-advanced or metastatic breast cancer patients treated with ado-trastuzumab emtansine (T-DM1) or capecitabine-plus-lapatinib.MethodsIn the IRT model, four latent well-being variables, based on FACT-B general subscales, were used to describe the physical, social/family, emotional and functional well-being. Each breast cancer subscale item was reassigned to one of the other subscales. Longitudinal changes in FACT-B responses and covariate effects were investigated.ResultsThe IRT model could describe both item-level and subscale-level FACT-B data. Non-Asian patients showed better baseline social/family and functional well-being than Asian patients. Moreover, patients with Eastern Cooperative Oncology Group performance status of 0 had better baseline physical and functional well-being. Well-being was described as initially increasing or decreasing before reaching a steady-state, which varied substantially between patients and subscales. T-DM1 exposure was not related to any of the latent variables. Physical well-being worsening was identified in capecitabine-plus-lapatinib-treated patients, whereas T-DM1-treated patients typically stayed stable.ConclusionThe developed framework provides a thorough description of FACT-B longitudinal data. It acknowledges the multi-dimensional nature of the questionnaire and allows covariate and exposure effects to be evaluated on responses.Electronic supplementary materialThe online version of this article (10.1007/s11095-018-2403-8) contains supplementary material, which is available to authorized users.

3047 Background: Apo2L/TRAIL (Apo2L ligand/tumor necrosis factor-related apoptosis-inducing ligand) is the first recombinant human protein that selectively induces apoptosis or programmed cell death in cancer cells while sparing normal cells. The molecule used in this joint clinical development between Genentech, Inc. and Amgen, Inc., is an optimized recombinant human Apo2L/TRAIL protein produced in E. coli. It displays broad activity in preclinical models of a variety of solid and hematologic cancers. This is the first report of the pharmacokinetics of Apo2L/TRAIL in humans. Methods: Thirty-nine patients enrolled in a phase 1a study had PK assessments at dose levels ranging from 0.5–15 mg/kg in two cohorts, those with and those without liver metastases. Recombinant human Apo2L/TRAIL was administered as a 1-hr IV infusion for 5 consecutive days over a 21-day cycle. Serum concentrations were determined using a sensitive ELISA assay. PK calculations were performed using Non-compartmental analyses. Results: Currently Apo2L/TRAIL PK data are available for 27 patients, 15 in cohort 1 (no liver metastases) and 12 in cohort 2 (liver metastases). Mean (± SD) PK data for patients in cohort 1 and cohort 2 did not differ. PK data for cohort 1 are outlined in the table below. Apo2L/TRAIL clearance appeared proportional to dose and consistent with that predicted from nonclinical models. Cmax achieved at doses ≥ 4 mg/kg are equivalent to or greater than those displaying activity in preclinical models. There was no evidence of drug accumulation between day 1 and day 5 of treatment. Conclusions: Apo2L/TRAIL at doses which can be safely administered in humans produces serum concentrations consistent with those demonstrating efficacy in tumor xenograft models. Hepatic metastases with or without mild liver dysfunction do not appear to influence the PK of Apo2L/TRAIL. [Table: see text] [Table: see text]

In vitro, erlotinib (0-30 µmol/l) and C-labelled midazolam (MDZ) (5 µmol/l) were incubated with human liver microsomes; separately, microsomes were preincubated with erlotinib (10 µmol/l) before the addition of MDZ. Results showed a time-dependent inhibition of MDZ metabolism by erlotinib, with a Ki of 7.5 µmol/l and an inactivation rate constant of 0.009/min. Patients with cancer (n=24) received a single oral dose of 7.5 mg MDZ and a single intravenous dose of 3 µCi [C-N-methyl] erythromycin on days 1, 8, 14 and 21. Patients also received 150 mg oral erlotinib daily from day 8 to day 14. Plasma concentrations of erlotinib and OSI-420 were determined on days 8 and 14; MDZ and 1'-hydroxymidazolam were determined on days 1, 8, 14 and 21. Coadministration of erlotinib resulted in a 4 and a 16% increase in CO2 on days 8 and 14, respectively, after the administration of erythromycin. The mean AUC0-last of MDZ decreased 17 and 34% after erlotinib treatment on day 8 and day 14, respectively. The half-life of MDZ and the AUC ratio of 1'-hydroxymidazolam to MDZ were not significantly changed. Although erlotinib may be a weak mechanism-based irreversible inhibitor of CYP3A4 in vitro, in vivo, erlotinib did not inhibit CYP3A-mediated metabolism, as determined by the erythromycin breath test and the MDZ pharmacokinetics. The mechanism for reduced exposure of MDZ is unclear, but may be because of an increase in intestinal metabolism or decreased absorption. These findings suggest that coadministration of erlotinib may not result in clinically relevant increases in exposure of CYP3A substrates.

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