Ivan Nestorov

Phase 3 study of recombinant factor VIII Fc fusion protein in severe hemophilia A

This phase 3 pivotal study evaluated the safety, efficacy, and pharmacokinetics of a recombinant FVIII Fc fusion protein (rFVIIIFc) for prophylaxis, treatment of acute bleeding, and perioperative hemostatic control in 165 previously treated males aged ≥12 years with severe hemophilia A. The study had 3 treatment arms: arm 1, individualized prophylaxis (25-65 IU/kg every 3-5 days, n = 118); arm 2, weekly prophylaxis (65 IU/kg, n = 24); and arm 3, episodic treatment (10-50 IU/kg, n = 23). A subgroup compared recombinant FVIII (rFVIII) and rFVIIIFc pharmacokinetics. End points included annualized bleeding rate (ABR), inhibitor development, and adverse events. The terminal half-life of rFVIIIFc (19.0 hours) was extended 1.5-fold vs rFVIII (12.4 hours; P < .001). Median ABRs observed in arms 1, 2, and 3 were 1.6, 3.6, and 33.6, respectively. In arm 1, the median weekly dose was 77.9 IU/kg; approximately 30% of subjects achieved a 5-day dosing interval (last 3 months on study). Across arms, 87.3% of bleeding episodes resolved with 1 injection. Adverse events were consistent with those expected in this population; no subjects developed inhibitors. rFVIIIFc was well-tolerated, had a prolonged half-life compared with rFVIII, and resulted in low ABRs when dosed prophylactically 1 to 2 times per week.

A Novel PEGylated Interferon Beta-1a for Multiple Sclerosis: Safety, Pharmacology, and Biology

This study clinically evaluated a novel PEGylated form of interferon beta‐1a (PEG‐IFN beta‐1a), a potential first‐line treatment for relapsing multiple sclerosis, in healthy volunteers. Two randomized, blinded phase I studies were conducted: a single‐dose study (n = 60) comparing subcutaneous or intramuscular PEG‐IFN beta‐1a (63, 125, or 188 μg) with intramuscular unmodified IFN beta‐1a 30 μg and a multiple‐dose study (n = 69) comparing subcutaneous PEG‐IFN beta‐1a dosed once every 2 or 4 weeks with placebo. Assessments included pharmacokinetic and pharmacodynamic (serum neopterin and 2′,5′‐OAS) measures, exploratory immune assessments, safety, and tolerability. A dose‐proportional increase in PEG‐IFN beta‐1a exposure was observed, with a 4‐fold greater exposure at 63 μg (6 million international units [MIU]) of PEG‐IFN beta‐1a than with 30 μg (6 MIU) intramuscular unmodified IFN beta‐1a. Increases in neopterin and 2′,5′‐OAS levels and changes in T helper cell pathway gene expression and lymphocyte subsets were greater and more sustained with PEG‐IFN beta‐1a than with unmodified IFN beta‐1a. PEG‐IFN beta‐1a was well tolerated, with only transient reductions in absolute neutrophils and some lymphocytes. Flu‐like symptoms were a commonly reported adverse event. These data support the continued clinical development of PEG‐IFN beta‐1a as a potentially effective treatment for patients with relapsing multiple sclerosis.

Tolerability and Pharmacokinetics of Delayed-Release Dimethyl Fumarate Administered With and Without Aspirin in Healthy Volunteers

BACKGROUND Delayed-release dimethyl fumarate (DR-DMF) has cytoprotective and antiinflammatory properties and has recently been approved in the United States as an oral treatment for relapsing forms of multiple sclerosis. The most common adverse events associated with DR-DMF are flushing and gastrointestinal (GI) events, the incidences of which diminish over time. OBJECTIVE The purpose of this study was to evaluate the tolerability and pharmacokinetic (PK) profile of DR-DMF with or without concomitant acetylsalicylic acid (aspirin), a cyclooxygenase inhibitor. METHODS Healthy volunteers (N = 56) were randomized to receive different dosing regimens of DR-DMF or matching placebo with or without pretreatment with 325 mg aspirin for 4 days. Plasma levels of the active metabolite monomethyl fumarate were assessed on days 1 and 4. Flushing and GI events were assessed using patient-reported scales. Potential flushing mediators were explored. RESULTS DR-DMF showed a safety, tolerability, and PK profile consistent with previous clinical experience, with no evidence of accumulation. Pretreatment with aspirin had no effect on the primary PK parameters, AUC0-10h, or Cmax. Flushing severity, assessed by 2 subject-reported rating scales, was generally mild and was rated highest at the start of treatment. Pretreatment with aspirin reduced flushing incidence and intensity without affecting GI events or the PK profile of DR-DMF. In some DR-DMF-treated individuals, plasma concentrations of a prostaglandin D2 (PGD2) metabolite were increased. CONCLUSIONS In healthy volunteers, DR-DMF was well tolerated over 4 days of dosing, with a PK profile consistent with that previously reported and no evidence of accumulation. Aspirin pretreatment reduced the incidence and intensity of flushing without affecting GI events or the DR-DMF PK profile. Elevated levels of PGD2 in some DR-DMF-treated individuals suggest that flushing may be, at least in part, prostaglandin mediated. ClinicalTrials.gov identifier: ID: NCT01281111.

PEGylated Interferon Beta-1a: Meeting an Unmet Medical Need in the Treatment of Relapsing Multiple Sclerosis

Multiple sclerosis is a chronic autoimmune disease of the central nervous system for which a number of disease-modifying therapies are available, including interferon beta (Avonex®, Rebif®, and Betaseron/Betaferon®), glatiramer acetate (Copaxone®), and an anti-VLA4 monoclonal antibody (Tysabri®). Despite the availability and efficacy of these protein and peptide drugs, there remains a significant number of patients who are untreated, including those with relatively mild disease who choose not to initiate therapy, those wary of injections or potential adverse events associated with therapy, and those who have stopped therapy due to perceived lack of efficacy. Since these drugs have side effects that may affect a patients decision to initiate and to remain on treatment, there is a need to provide a therapy that is safe and efficacious but that requires a reduced dosing frequency and hence a concomitant reduction in the frequency of side effects. Here we describe the development of a PEGylated form of interferon beta-1a that is currently being tested in a multicenter, randomized, double-blind, parallel-group, placebo-controlled study in relapsing multiple sclerosis patients, with the aim of determining the safety and efficacy of 125 microg administered via the subcutaneous route every 2 or 4 weeks.

Recombinant factor VIII Fc fusion protein: extended-interval dosing maintains low bleeding rates and correlates with von Willebrand factor levels

Routine prophylaxis with replacement factor VIII (FVIII) – the standard of care for severe hemophilia A – often requires frequent intravenous infusions (three or four times weekly). An FVIII molecule with an extended half‐life could reduce infusion frequency. The A‐LONG study established the safety, efficacy and prolonged pharmacokinetics of recombinant FVIII Fc fusion protein (rFVIIIFc) in previously treated adolescents and adults with severe hemophilia A.

In Vivo Pharmacology and Toxicology Evaluation of Polyethylene Glycol-Conjugated Interferon β-1a

Human interferon (IFN) β has well established beneficial effects in treating relapsing forms of multiple sclerosis, but current first-line treatment requires frequent (from daily to weekly) parenteral administration. A 20-kDa polyethylene glycol (PEG)-conjugated IFN β-1a (PEG-IFN β-1a) is being developed to decrease the frequency of administration and improve patient convenience and compliance. We present pharmacokinetic (PK) and pharmacodynamic (PD) parameters, immunogenicity, and safety of PEG-IFN β-1a in Rhesus monkeys in support of a phase 1 clinical trial. Two single-dose PK/PD studies and one 5-week repeat-dose toxicity study compliant with good laboratory practice were conducted. The PK of IFN β-1a and PEG-IFN β-1a were modeled with a two-compartment model, and the link between drug concentration and neopterin response (PD marker) was described with an indirect stimulatory model. PEG-IFN β-1a showed greater exposure, longer half-life, lower clearance, and reduced volume of distribution than unmodified IFN β-1a. Consistent with the pharmacology of type I IFNs, PEG-IFN β-1a resulted in the elevation of neopterin concentration, a transient body temperature increase, and a reversible lymphocyte count decrease. As expected, neutralizing antibodies to PEG-IFN β-1a formed in almost all monkeys after 5 weeks of treatment, which resulted in significantly reduced drug exposure and abrogation of neopterin induction. There were no drug-related adverse effects at doses up to 100 μg/kg (11 MIU/kg) given subcutaneously or intramuscularly once weekly for 5 weeks. The no-observed-adverse-effect level was determined to be 100 μg/kg (11 MIU/kg), the highest dose tested.

Population pharmacokinetics of recombinant factor VIII Fc fusion protein

Population pharmacokinetics (PK) of FVIII activity‐time profiles following recombinant factor VIII Fc fusion protein (rFVIIIFc) and recombinant factor VIII (rFVIII) dosing were evaluated in previously treated patients with severe hemophilia A (from two clinical trials). Potential covariates that may be determinants of variability in FVIII activity were identified. A 2‐compartment model adequately described the PK of both compounds. von Willebrand Factor (VWF) concentration was the major covariate for rFVIIIFc clearance, reflecting its protective role in FVIII activity clearance. The effect of body weight and hematocrit on the central volume of distribution of rFVIIIFc was minor. The results of these analyses confirmed that rFVIIIFc clearance (1.65 dL/h) is much lower than that of rFVIII (2.53 dL/h), while the steady state volumes of distribution were similar. The strong positive correlations between the PK parameters of rFVIIIFc and rFVIII suggest that individuals who have high time‐related PK characteristics with rFVIII are likely to have comparable characteristics with rFVIIIFc. Steady‐state activity‐time profiles for selected rFVIIIFc dosing regimens were simulated accounting for uncertainty in model parameters. These population PK analyses and simulations provide a comprehensive characterization of the PK of rFVIIIFc and rFVIII and may be useful for designing dosing regimens.

COMPARE: Pharmacokinetic profiles of subcutaneous peginterferon beta‐1a and subcutaneous interferon beta‐1a over 2 weeks in healthy subjects

Aim Subcutaneous (s.c.) peginterferon beta‐1a injected once every 2 weeks and s.c. interferon beta‐1a injected three times per week (Rebif®) have demonstrated efficacy in relapsing–remitting multiple sclerosis, but direct comparisons of pharmacological activity and tolerability between the two products are lacking. COMPARE was an open label, crossover, pharmacokinetic (PK) study evaluating drug exposure and the safety and tolerability of s.c. peginterferon beta‐1a and s.c. interferon beta‐1a, over 2 weeks in healthy subjects. Methods Thirty healthy subjects received one dose of peginterferon beta‐1a (125 μg s.c.) or six doses of interferon beta‐1a (44 μg s.c.) over 2 weeks, followed by the alternate treatment after a 2 week washout period. Drug concentrations were measured using an enzyme‐linked immunosorbent assay (ELISA) and PK parameters including cumulative area under the concentration–time curve (AUC0‐336h) over 2 weeks and maximum observed serum concentrations (C max) were estimated using a non‐compartmental analysis. Results The PK analysis population comprised 26 subjects for each treatment. Drug exposure (AUC0‐336h) was 60% higher with s.c. peginterferon than with s.c. interferon beta‐1a (117.4 ng ml−1h, 95% confidence interval 95.6, 144.3 vs. 73.1 ng ml−1 h, 95% confidence interval 61.2, 87.3, respectively; P < 0.0001). Injection‐site reactions (ISRs) were the most common adverse events (AEs) observed with both treatments. Numerically lower frequencies and incidence rates of ISRs, headache, myalgia and chills were observed with s.c. peginterferon beta‐1a. Conclusions One dose of s.c. peginterferon delivered significantly greater drug exposure than s.c. interferon beta‐1a three times a week over 2 weeks, and a lower frequency of AEs.

Pharmacokinetics, pharmacodynamics, and safety of peginterferon beta‐1a in subjects with normal or impaired renal function

Peginterferon beta‐1a was efficacious in a Phase 3 relapsing multiple sclerosis trial, and its safety profile was consistent with other beta interferons. This study evaluated the impact of renal impairment on the pharmacokinetics and pharmacodynamics (neopterin elevation; a biomarker of pharmacological activity induced by interferon beta‐1a) of peginterferon beta‐1a following a single subcutaneous dose at 63 μg (n = 5) or 125 μg (n = 30). The results showed a fractional increase in area‐under‐the‐concentration‐time curve (AUC [30–53%]) and peak serum concentration (Cmax [26–42%]) in subjects with mild, moderate, and severe renal impairment, versus healthy subjects; AUC and Cmax were similar for healthy subjects and end‐stage‐renal‐disease patients receiving hemodialysis. Pharmacokinetic simulation showed that the steady state concentration overlapped in the majority of healthy subjects and subjects with severe renal impairment. Neopterin baseline, peak concentration, and AUC increased as renal function decreased. Peginterferon beta‐1a was well tolerated in all groups. These results do not warrant peginterferon beta‐1a dose adjustment in subjects with renal impairment.

Quantitation and pharmacokinetic modeling of therapeutic antibody quality attributes in human studies

ABSTRACT A thorough understanding of drug metabolism and disposition can aid in the assessment of efficacy and safety. However, analytical methods used in pharmacokinetics (PK) studies of protein therapeutics are usually based on ELISA, and therefore can provide a limited perspective on the quality of the drug in concentration measurements. Individual post-translational modifications (PTMs) of protein therapeutics are rarely considered for PK analysis, partly because it is technically difficult to recover and quantify individual protein variants from biological fluids. Meanwhile, PTMs may be directly linked to variations in drug efficacy and safety, and therefore understanding of clearance and metabolism of biopharmaceutical protein variants during clinical studies is an important consideration. To address such challenges, we developed an affinity-purification procedure followed by peptide mapping with mass spectrometric detection, which can profile multiple quality attributes of therapeutic antibodies recovered from patient sera. The obtained data enable quantitative modeling, which allows for simulation of the PK of different individual PTMs or attribute levels in vivo and thus facilitate the assessment of quality attributes impact in vivo. Such information can contribute to the product quality attribute risk assessment during manufacturing process development and inform appropriate process control strategy.