Blueprint for antibody biologics developability.

Large-molecule antibody biologics have revolutionized medicine owing to their superior target specificity, pharmacokinetic and pharmacodynamic properties, safety and toxicity profiles, and amenability to versatile engineering. In this review, we focus on preclinical antibody developability, including its definition, scope, and key activities from hit to lead optimization and selection. This includes generation, computational and in silico approaches, molecular engineering, production, analytical and biophysical characterization, stability and forced degradation studies, and process and formulation assessments. More recently, it is apparent these activities not only affect lead selection and manufacturability, but ultimately correlate with clinical progression and success. Emerging developability workflows and strategies are explored as part of a blueprint for developability success that includes an overview of the four major molecular properties that affect all developability outcomes: 1) conformational, 2) chemical, 3) colloidal, and 4) other interactions. We also examine risk assessment and mitigation strategies that increase the likelihood of success for moving the right candidate into the clinic.

Safety, efficacy and pharmacokinetics of peginterferon alpha2a (40 kd) in children with chronic hepatitis C.

Chronic hepatitis C virus (HCV) infection in children is a problem affecting thousands of children worldwide. Although standard interferon (INF) has better efficacy in pediatric patients than in adults, results in children with genotype 1 are poor; response rates to combination treatment with standard INF and ribavirin are better but the treatment requires thrice-weekly injections. The improved antiviral efficacy of weekly pegylated interferons relative to standard interferons in adults with chronic HCV infection suggests that pegylated interferons may also improve antiviral efficacy in children. We therefore investigated the pharmacokinetics, efficacy and safety of peginterferon alpha2a (pegINF-alpha2a) (40 kd) in 14 children ages 2 to 8 years with chronic hepatitis C (13 genotype 1, 1 non-1 genotype). Drug dose was calculated from each patient's body surface area (BSA) according to the formula BSA (m2)/(1.73 m2) x 180 microg, and patients were administered once-weekly subcutaneous injections for 48 weeks. Viral load and pharmacokinetic parameters were determined from blood drawn throughout the study and during follow-up. At week 24, the mean trough concentration was about 20% below values obtained from adults treated with pegINF-alpha2a, and the area under the curve from 0 to 168 hours was about 20% above adult values, suggesting that drug doses calculated from BSA achieved therapeutically adequate concentrations. Six of 14 patients (43%), all infected with genotype 1, achieved a sustained virological response. Adverse events were those commonly associated with INF-based treatment, and none was deemed serious. In conclusion, our findings provide a basis for larger studies evaluating the efficacy and safety of pegINF-alpha2a as monotherapy as well as in combination with ribavirin in pediatric patients with chronic hepatitis C.

Peginterferon alfa-2a does not alter the pharmacokinetics of methadone in patients with chronic hepatitis C undergoing methadone maintenance therapy.

OBJECTIVE: Our objective was to quantify the pharmacokinetics of methadone and the pharmacokinetics and pharmacodynamics of peginterferon alfa-2a (40 kd) in patients with chronic hepatitis C undergoing methadone maintenance therapy. METHODS: Adults with chronic hepatitis C who had been receiving a consistent methadone maintenance regimen for at least 3 months were eligible for this open-label, multicenter, nonrandomized drug interaction study. All patients received 180 microg subcutaneous peginterferon alfa-2a once weekly for 4 weeks and continued their methadone regimen. Serial blood samples were collected at baseline and immediately before and for up to 168 hours after study drug administration for the purposes of quantifying methadone and peginterferon alfa-2a serum concentrations, measuring serum 2',5'-oligoadenylate synthetase activity, and determining hepatitis C virus ribonucleic acid levels. RESULTS: Twenty-four patients were enrolled. Methadone exposure, as measured by maximum serum concentration (C(max)) and area under the concentration-time curve (AUC) normalized to a 100-mg/d dose, after 4 doses of peginterferon alfa-2a increased by 10% to 15% when compared with baseline. The week 4/baseline ratio of the mean C(max) was 1.11 (90% confidence interval [CI], 1.02-1.22), and for AUC from time 0 to 24 hours, the week 4/baseline ratio was 1.15 (90% CI, 1.08-1.23). The mean accumulation ratios (week 4/first dose) for C(max) and AUC from time 0 to 168 hours of peginterferon alfa-2a were 2.1 and 2.3, respectively. CONCLUSIONS: Peginterferon alfa-2a does not appreciably alter the pharmacokinetics of methadone.

Amelioration of nephropathy in mice expressing HIV-1 genes by the cyclin-dependent kinase inhibitor flavopiridol.

Cumulative evidence suggests that human immunodeficiency virus-associated nephropathy (HIVAN), the third leading cause of end-stage renal disease in African-Americans, may respond to therapeutic strategies that interrupt HIV-1 expression in infected renal epithelium. We recently demonstrated that suppression of HIV-1 transcription in infected glomerular visceral epithelial cells by flavopiridol, a small-molecule inhibitor of the cyclin-dependent kinases required for HIV-1 promoter activity, reversed HIV-induced proliferation and dedifferentiation in vitro. To address whether flavopiridol could ameliorate HIV-induced renal disease, we utilized a well-established HIV-1 NL4-3 transgenic mouse model of HIVAN. HIV-1 proviral transgene expression in whole kidney was markedly suppressed by a 20 day treatment with flavopiridol. Following treatment, histopathological, serological and urinary indices of nephrosis were normalized in flavopiridol-treated but not in vehicle-treated transgenics. Microarray analysis showed that 82% of the dysregulated genes in HIVAN kidney were normalized to control levels by flavopiridol, whereas continued dysregulation of most of the remaining 18% was attributable to an effect from flavopiridol alone. These results demonstrate for the first time that targeting the cyclin-dependent kinases that support HIV-1 expression can ameliorate HIV-induced disease in an animal model.

Modeling nicotine arterial-venous differences to predict arterial concentrations and input based on venous measurements: application to smokeless tobacco and nicotine gum.

Significant arterio-venous differences in nicotine concentrations have been observed during and after cigarette smoking, nicotine nasal spray, and intravenous nicotine administration. In this paper we describe a novel mathematical method for estimating arterial blood levels from venous blood level data. The model allows to quantify: (i) the influence of the microcirculation in the hands and forearm on the distribution of nicotine, and (ii) the influence of disregarding the venous to arterial circulation in the estimate of systemic inputs. We also (iii) propose a general method to predict arterial concentrations and inputs given venous data. The basic model we adopt is based on the relationship Cv = T * Ca, where Cv and Ca are the concentration in the venous and arterial site, respectively, T is the arterio-venous transfer function and * indicates convolution. We use empirical data to estimate T. We then compare estimates of systemic inputs to the venous site obtained taking into account the transfer function or, as usually done, disregarding it. The relationship we use to compare estimated inputs are: Cv = T * ka * A (where Ka is the arterial disposition function and A the systemic input), and Cv = Kv * A (where Kv is the venous disposition function), respectively. Finally, the estimated transfer function allows to estimate (average) Ca or A given arbitrary venous data. (i) Our analysis suggests that a bi-exponential T is needed to describe observed arterial-venous differences. The estimated transfer function indicates that no elimination of nicotine is involved in the forearm. (ii) Disregarding T, as usually done, erroneously obtains too complex venous input functions (because these input functions incorporate T). (iii) Disregarding T erroneously estimates significantly higher total inputs. (iv) Using the proposed model and previously published venous nicotine level data we predict substantial arterial-venous differences in blood nicotine levels for smokeless tobacco and nicotine gum. The use of disposition functions obtained from venous data may lead to erroneous estimation of the rates of entry into the circulation and systemic bioavailability for many drugs.