Biotherapeutic bioanalysis: a multi-indication case study review.

A thorough understanding of the structure and biology of a biotherapeutic is crucial to defining a suitable strategy for pharmacokinetic characterization in proof-of-concept disease models, toxicology species as well as the healthy and disease indication patient populations. This manuscript summarizes parameters that impact bioanalytical strategy for over 50 biotherapeutics indicated for the treatment of oncology, rheumatoid arthritis, allergy, multiple sclerosis, hematology, metabolism and infectious disease. We have addressed numerous therapeutic modalities including chimeric, humanized and fully human monoclonal antibodies, replacement proteins, peptides and fusion proteins, including polyethylene glycol and Fc fusions, as well as antibody-drug conjugates. With the rapid evolution of biotherapeutics over the last 20 years and the contraction of the pharmaceutical and biotechnology labor force, efficient workflow management becomes a crucial bioanalytical component. Thus, we have also addressed new technologies that have demonstrated either increased throughput or enhanced characterization, including Meso Scale Discovery, Gyrolab and affinity MS.

Effects of multiple-dose pegylated interferon alfa-2b on the activity of drug-metabolizing enzymes in persons with chronic hepatitis C.

PURPOSE: To examine the effect of pegylated interferon (PEG-IFN) alfa-2b on the activity of major drug-metabolizing enzymes. METHODS: This nonrandomized, open-label, multiple-dose study examined the effects of PEG-IFN alfa-2b on the activity of CYP450 1A2, 2 C8/9, 2D6, and 3A4 enzymes and N-acetyltransferase in subjects with chronic hepatitis C. Eligible subjects received PEG-IFN alfa-2b 1.5 µg/kg subcutaneously once weekly for 4 weeks (days 3, 10, 17, and 24). Oral probe substrates (dextromethorphan hydrobromide 45 mg, caffeine 200 mg, tolbutamide 500 mg, and dapsone 100 mg) were administered after a 10-h fast on days 1 and 25. Midazolam 4 mg was administered orally on days 2 and 26. Enzyme activity for each CYP450 isozyme and for N-acetyltransferase was estimated based on the ratios of the observed concentrations of the substrates and metabolites in plasma or urine samples. RESULTS: Twenty-six subjects enrolled in the study. Mean age was 44.3 years, mean weight was 78.9 kg, and mean body mass index was 26.3 kg/m(2). Multiple doses of PEG-IFN alfa-2b inhibited CYP1A2 activity to a limited extent (point estimate = 84.2%, 90% confidence interval [CI] 79-90), increased CYP2C8/9 activity to a limited extent (point estimate = 127.6%, 90% CI 115-142), increased CYP2D6 activity (point estimate = 167%, 90% CI 125-223), and had no effect on the activity of CYP3A4 or N-acetyltransferase. CONCLUSION: Weekly administration of PEG-IFN alfa-2b to subjects with chronic hepatitis C increased CYP2C8/9 and CYP2D6 activity in some individuals.

Multiple-dose pharmacokinetics of peginterferon alfa-2b in patients with renal insufficiency.

AIM: To evaluate the safety, tolerability and multiple-dose pharmacokinetics of pegylated interferon (PEG-IFN) alfa-2b in patients with moderate or severe renal insufficiency and in those with normal renal function. METHODS: In an open-label study, subjects with normal renal function (creatinine clearance >80 ml min(-1) per 1.73 m2) and patients with moderate (30-50 ml min(-1) per 1.73 m2) or severe (10-29 ml(-1) min(-1) per 1.73 m2) renal impairment received weekly injections of PEG-IFN alfa-2b (1.0 microg kg(-1)) for 4 weeks. Safety assessments were made before each injection and blood samples were taken up to 168 h after the final dose. RESULTS: Renal insufficiency increased PEG-IFN alfa-2b exposure. Area under the curve for 0-tau (dosing interval of 168 h), AUC(tau), was increased 30% and 120% in patients with moderate or severe renal insufficiency, respectively. Mean maximum serum concentration was almost doubled in patients with severe insufficiency [1305.8 pg ml(-1); 95% confidence interval (CI) 825, 1786] compared with subjects with normal renal function (731.4 pg ml(-1); 95% CI 407, 1056), whereas the apparent volume of distribution was reduced (0.80 l kg(-1)vs. 1.28 l kg(-1), respectively). Elimination half-life was extended in patients with moderate and severe renal insufficiency (65.6 h and 64.9 h, respectively) compared with subjects with normal renal function (51.5 h). Significant differences were observed in the AUC and C(max) values of patients with severe renal dysfunction, compared with those who had normal renal function (P < 0.05; Kruskal-Wallis test). PEG-IFN alfa-2b was well tolerated and adverse events were similar in both treatment groups. CONCLUSIONS: Exposure to PEG-IFN alfa-2b is increased in patients with renal insufficiency, suggesting that doses of the drug should be reduced by 50% in patients with severe renal insufficiency and by 25% in those with moderate insufficiency.

The effect of multiple doses of peginterferon alfa-2b on the steady-state pharmacokinetics of methadone in patients with chronic hepatitis C undergoing methadone maintenance therapy.

This multicenter, open-label study evaluated the effects of multiple doses of peginterferon alfa-2b on the steadystate pharmacokinetics of methadone in 20 adults with hepatitis C virus infection who were enrolled in a methadone maintenance program. All subjects received peginterferon alfa-2b 1.5 mug/kg/wk for 4 weeks and maintained their normal methadone regimen. Serial blood samples were collected immediately before the first and after the fourth peginterferon alfa-2b dose (day 23). At day 23, exposure to the active methadone R-enantiomer increased by approximately 15% following administration of peginterferon alfa-2b, with 90% confidence intervals just outside the bioequivalence criteria (range, 80%-125%). Similar increases in exposure (C(max), AUC(0-24), and AUC(last)) were observed with S-methadone and total methadone. Peginterferon alfa-2b was well tolerated. Peginterferon alfa-2b is associated with minor increases in exposure to methadone in individuals with hepatitis C virus infection; however, these increases are unlikely to be clinically meaningful and are not associated with any safety concerns.

Dose selection and population pharmacokinetics of PEG-Intron in patients with chronic myelogenous leukaemia.

AIMS: To assess the dose selection using population pharmacokinetics of Pegylated Intron-alpha2b (PEG-Intron) in patients with chronic myelogenous leukaemia (CML). METHODS: PEG-Intron 3-6 microg kg(-1) was administered subcutaneously once a week and blood samples were collected up to 48 weeks of treatment. A total of 624 samples collected from 137 patients were included in the analysis. Nonlinear mixed-effects modelling was used to analyse the sparsely sampled concentration data from a clinical efficacy trial. Covariates in the analysis included weight, sex, age, race, serum creatinine and estimated creatinine clearance (CLcr). RESULTS: The apparent clearance of PEG-Intron decreased after repeated dosing. The clearance at treatment week 4 was 42.3 l day(-1) (patients with CLcr 120 ml min(-1)) with interpatient variability 30%. At treatment week 48, the clearance value was reduced to 69% of its week 4 value. CLcr, a composite variable calculated from body weight, sex, age and serum creatinine, had a small but statistically significant influence on the clearance of PEG-Intron. The clearance of PEG-Intron in patients with CML was 40% higher than that of hepatitis C virus-infected patients. CONCLUSION: The dose of PEG-Intron 6.0 microg kg(-1) week(-1) appeared appropriate in the treatment of patients with CML.