Comparative Bioavailability of Two Formulations of Biopharmaceutical Classification System (BCS) Class IV Drugs: A Case Study of Lopinavir/Ritonavir.

BACKGROUND: Lopinavir/ritonavir (LPV/r-A, Kaletra®), a fixed dose, co-formulated antiviral therapy for the treatment of HIV infection has been used worldwide for over two decades. Both active substances have low solubility in water and low membrane permeability. LPV/r-A tablets contain key excipients critical to ensuring acceptable bioavailability of lopinavir and ritonavir in humans. An established dog pharmacokinetic model demonstrated several generic LPV/r tablet formulations have significant oral bioavailability variability compared to LPV/r-A. METHODS: Analytical characterizations of LPV/r-B tablets were performed and a clinical study was conducted to assess the relative bioavailability of Kalidavir® (LPV/r-B) 400/100 mg tablets relative to Kaletra® (LPV/r-A) 400/100 mg tablets under fasting conditions. RESULTS: The presence of active substances were confirmed in LPV/r-B tablets in an apparent amorphous state at essentially the labeled amounts, and dissolution profiles were generally similar to LPV/r-A tablets. Excipients in the tablet formulation were found to be variable and deviate from the labeled composition. Lopinavir and ritonavir exposures (AUC) following LPV/r-B administration were approximately 90% and 20% lower compared to that of LPV/r-A. CONCLUSIONS: LPV/r-B was not shown to be bioequivalent to LPV/r-A.

Safety, pharmacokinetics, and antitumor response of depatuxizumab mafodotin as monotherapy or in combination with temozolomide in patients with glioblastoma.

Background: We recently reported an acceptable safety and pharmacokinetic profile of depatuxizumab mafodotin (depatux-m), formerly called ABT-414, plus radiation and temozolomide in newly diagnosed glioblastoma (arm A). The purpose of this study was to evaluate the safety and pharmacokinetics of depatux-m, either in combination with temozolomide in newly diagnosed or recurrent glioblastoma (arm B) or as monotherapy in recurrent glioblastoma (arm C). Methods: In this multicenter phase I dose escalation study, patients received depatux-m (0.5-1.5 mg/kg in arm B, 1.25 mg/kg in arm C) every 2 weeks by intravenous infusion. Maximum tolerated dose (MTD), recommended phase II dose (RP2D), and preliminary efficacy were also determined. Results: Thirty-eight patients were enrolled as of March 1, 2016. The most frequent toxicities were ocular, occurring in 35/38 (92%) patients. Keratitis was the most common grade 3 adverse event observed in 6/38 (16%) patients; thrombocytopenia was the most common grade 4 event seen in 5/38 (13%) patients. The MTD was set at 1.5 mg/kg in arm B and was not reached in arm C. RP2D was declared as 1.25 mg/kg for both arms. Depatux-m demonstrated a linear pharmacokinetic profile. In recurrent glioblastoma patients, the progression-free survival (PFS) rate at 6 months was 30.8% and the median overall survival was 10.7 months. Best Response Assessment in Neuro-Oncology responses were 1 complete and 2 partial responses. Conclusion: Depatux-m alone or in combination with temozolomide demonstrated an acceptable safety and pharmacokinetic profile in glioblastoma. Further studies are currently under way to evaluate its efficacy in newly diagnosed (NCT02573324) and recurrent glioblastoma (NCT02343406).

Pharmacokinetics of the BCL-2 Inhibitor Venetoclax in Healthy Chinese Subjects.

Venetoclax has been approved in the United States, Europe, Canada, and Australia for appropriate patients with difficult-to-treat chronic lymphocytic leukemia (CLL). The objective of this phase 1 study was to evaluate the pharmacokinetics of venetoclax in Chinese subjects to inform the dose selection of venetoclax in a phase 2 study of patients with relapsed/refractory (R/R) CLL in China. Twelve healthy first-generation Han Chinese subjects received a single 100-mg dose of venetoclax following a low-fat breakfast. Pharmacokinetic parameters were estimated using noncompartmental methods. After a single dose of venetoclax in healthy Chinese subjects, the median time to peak concentration was 6 hours (range, 4 to 6 hours), and the mean ± SD Cmax , AUCinf , and terminal half-life were 1.0 ± 0.32 µg/mL, 12.6 ± 5.4 µg·h/mL, and 18.4 ± 2.97 hours, respectively. On average, venetoclax Cmax and AUCinf values were 94% and 66% higher, respectively, in Chinese subjects compared with those observed historically for non-Asian subjects receiving the same dose. Based on these pharmacokinetic results and the established exposure-response relationship of venetoclax in non-Asian CLL subjects, a 400-mg once-daily dosage regimen was selected for evaluating the venetoclax pharmacokinetics, efficacy, and safety in the venetoclax phase 2 open-label study in Chinese subjects with R/R CLL.

Evaluation of the effect of the EGFR antibody-drug conjugate ABT-414 on QT interval prolongation in patients with advanced solid tumors likely to over-express EGFR.

PURPOSE: ABT-414 is an antibody-drug conjugate (ADC) being developed for the treatment of tumors harboring amplification of the epidermal growth factor receptor (EGFR). This study evaluated the potential of ABT-414 to prolong the QT interval as part of the initial phase 1 study (NCT01741727). METHODS: Data from patients who received ABT-414 monotherapy at a dose of 1-4 mg/kg once every 3 weeks or 1 or 1.5 mg/kg weekly for 2 out of every 3 weeks (alternate schedule) by intravenous infusion were included in the analysis of triplicate 12-lead ECGs obtained before dosing and through 168 h after dosing. Data from time-matched pharmacokinetic samples and QT interval assessments were evaluated using linear mixed-effects modeling to determine the effects of ABT-414, total ABT-806, and cysteine-maleimidocaproyl monomethyl auristatin F (Cys-mcMMAF) on the QT interval corrected using Fridericia's formula (QTcF). RESULTS: Fifty-one patients were included in the analyses. ABT-414 had no clinically meaningful effect on QTcF. Using pooled data from doses ≥2 mg/kg, the estimated mean ∆QTcF reached a maximum of 4.30 ms after dosing, with a one-sided 95% upper confidence bound of 8.32 ms. The exposure-response analysis showed no statistically significant relationship between ΔQTcF and the concentration of any analyte (P > 0.05). No patient had a QTcF value >480 ms or a ∆QTcF value >30 ms. CONCLUSIONS: ABT-414 had no clinically meaningful effect on the QTcF interval at doses being evaluated for treatment of patients with solid tumors.