A mechanistic pharmacokinetic model with drug and antidrug antibody interplay, and its application for assessing the impact of immunogenicity response on bioequivalence testing.

AIMS: Single-dose pharmacokinetic (PK) studies in healthy subjects have been the design of choice for bioequivalence determination for decades. This preference has been recently extended to PK similarity studies of proposed biosimilars. However, PK similarity studies can be complicated by the effect of immunogenicity response on drug disposition. The impact is exacerbated when there is an imbalance in host-specific immunological characteristics of subjects between the test and reference groups. Such complications remain poorly understood. The purpose of this communication is to show that the impact of immunogenicity response on PK similarity determination can be critical, using adalimumab as an example. METHODS: Data for adalimumab concentrations and immunogenicity response over 10 weeks were obtained from 133 healthy subjects receiving a 40 mg dose of Humira® in a PK similarity study. Also, a population PK model with a mechanistic construct for delineating the interplay between adalimumab disposition and antidrug antibodies response was utilized to estimate via simulation the probability that a PK similarity study would fail in typical study settings. RESULTS: The simulations showed that the immunogenicity response can have a profound impact on the outcome of PK similarity determination. As such, the probability of failing to achieve the similarity conclusion increased to 51.9%, from 13.8% in the absence of immunogenicity response. CONCLUSION: This study provides a model-based framework for better understanding of how a PK similarity study can be optimally designed and for interpretation of the outcome of PK similarity determination when the drug disposition is affected in the presence of immunogenicity response.

A comparative clinical study of PF-06410293, a candidate adalimumab biosimilar, and adalimumab reference product (Humira®) in the treatment of active rheumatoid arthritis.

BACKGROUND: This double-blind, randomized, 78-week study evaluated the efficacy, safety, immunogenicity, pharmacokinetics, and pharmacodynamics of PF-06410293, a candidate adalimumab biosimilar, versus adalimumab reference product (Humira®) sourced from the EU (adalimumab-EU) in biologic-naïve patients with active rheumatoid arthritis (RA) despite methotrexate (MTX) (10-25 mg/week). We report results for the first 26 weeks of treatment. METHODS: Patients with active RA (N = 597) were randomly assigned (1:1) to PF-06410293 or adalimumab-EU, while continuing with MTX treatment. The primary endpoint was American College of Rheumatology 20% improvement (ACR20) at week 12. Therapeutic equivalence was concluded if the two-sided 95% confidence interval (CI) for the ACR20 difference between the two arms was entirely contained within the symmetric equivalence margin (±14%). Additionally, a two-sided 90% CI was calculated by using an asymmetric equivalence margin (-12%, 15%). Secondary efficacy endpoints to week 26 included ACR20/50/70, change from baseline Disease Activity Score based on high-sensitivity C-reactive protein [DAS28-4(CRP)], European League Against Rheumatism (EULAR) response, DAS28-4(CRP) of less than 2.6, and ACR/EULAR remission. QuantiFERON-TB testing was performed at screening and week 26. RESULTS: Patients (78.7% of whom were female and whose mean age was 52.5 years) had a mean baseline RA duration of 6.8 years. The mean baseline DAS28-4(CRP) values were 5.9 (PF-06410293) and 6.1 (adalimumab-EU). The observed week-12 ACR20 values were 68.7% (PF-06410293) and 72.7% (adalimumab-EU) in the intention-to-treat population. With non-responder imputation, the treatment difference in week-12 ACR20 was -2.98% and corresponding CIs-95% CI (-10.38%, 4.44%) and 90% CI (-9.25%, 3.28%)-were entirely contained within the equivalence margins (symmetric and asymmetric, respectively). The secondary efficacy endpoints were similar between arms. Over 26 weeks, injection-site reactions occurred in 1.7% versus 2.0%, hypersensitivity events in 4.4% versus 8.4%, pneumonia in 0.7% versus 2.0%, and opportunistic infections in 2.4% versus 1.7% in the PF-06410293 and adalimumab-EU arms, respectively. One death due to myocardial infarction occurred (adalimumab-EU arm). Rates of anti-drug antibody incidence were 44.4% (PF-06410293) and 50.5% (adalimumab-EU). CONCLUSIONS: The study results demonstrate that efficacy, safety, and immunogenicity of PF-06410293 and adalimumab-EU were similar during the first 26 weeks of treatment in patients with active RA on background MTX. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02480153 . First posted on June 24, 2015; EU Clinical Trials Register EudraCT number: 2014-000352-29 . Start date: October 27, 2014.

A randomized controlled trial comparing PF-06438179/GP1111 (an infliximab biosimilar) and infliximab reference product for treatment of moderate to severe active rheumatoid arthritis despite methotrexate therapy.

BACKGROUND: This double-blind, active-controlled, randomized, multinational study evaluated the efficacy, safety, pharmacokinetics (PK), and immunogenicity of PF-06438179/GP1111 (IxifiTM/Zessly®), an infliximab biosimilar, vs infliximab (Remicade®) reference product sourced from the European Union (infliximab-EU) in biologic-naïve patients with moderate to severe active rheumatoid arthritis (RA) despite methotrexate therapy. This paper reports results from the initial 30-week treatment period. METHODS: Patients (N = 650) were stratified by geographic region and randomized 1:1 to PF-06438179/GP1111 or infliximab-EU (3 mg/kg intravenous at weeks 0, 2, and 6, then every 8 weeks). Dose escalation to 5 mg/kg was allowed starting at week 14 for patients with inadequate RA response. The primary endpoint was American College of Rheumatology criteria for ≥ 20% clinical improvement (ACR20) response at week 14. Therapeutic equivalence was declared if the two-sided 95% CI for the treatment difference was within the symmetric equivalence margin of ± 13.5%. Statistical analysis was also performed with a two-sided 90% CI using an asymmetric equivalence margin (- 12.0%, 15.0%). RESULTS: Patients (80.3% female; 79.4% seropositive) had a mean RA duration of 6.9 years, and mean baseline Disease Activity Score in 28 joints, four components based on C-reactive protein was 6.0 in both arms. Week 14 ACR20 in the intention-to-treat population was 62.7% for PF-06438179/GP1111 and 64.1% for infliximab-EU. Week 14 ACR20 using nonresponder imputation was 61.1% for PF-06438179/GP1111 and 63.5% for infliximab-EU, and the 95% (- 9.92%, 5.11%) and 90% (- 8.75%, 4.02%) CIs for the treatment difference (- 2.39%) were entirely contained within the prespecified symmetric and asymmetric equivalence margins, respectively. No differences were observed between arms for secondary efficacy endpoints. Overall postdose antidrug antibody (ADA) rates through week 30 were 48.6% and 51.2% for PF-06438179/GP1111 and infliximab-EU, respectively. Efficacy and immunogenicity were similar between treatments for patients with dose escalation (at or after week 14), as well as between treatments for patients without dose escalation. Safety profiles of PF-06438179/GP1111 and infliximab-EU were similar, with no clinically meaningful differences observed between arms, including after ADA development. Serum drug concentrations were similar between arms at each time point during the initial 30-week treatment period. CONCLUSION: PF-06438179/GP1111 and infliximab-EU demonstrated similar efficacy, safety, immunogenicity, and PK with or without dose escalation in patients with moderate to severe active RA on background methotrexate. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02222493 . Registered on 21 August 2014. EudraCT, 2013-004148-49 . Registered on 14 July 2014.

Biosimilars Have Arrived: Rituximab.

A biosimilar is a biologic product that is highly similar to a licensed biologic ("originator") such that there are no clinically meaningful differences in safety, purity, or potency between the biosimilar and the originator. As patent protection and data exclusivity for the biologic rituximab expire, several potential biosimilars to rituximab are in development, which could soon lead to the availability of numerous rituximab biosimilars. Biosimilars are evaluated using thorough and rigorous analyses of the potential biosimilar versus the originator biological to confirm similar structure, function, and clinical efficacy as well as safety. Approval of a biosimilar is based upon the totality of the evidence demonstrating similarity to the originator. An understanding of the process of the interchangeable designation of a biosimilar is important in the context of patient outcomes. We conducted an analysis of the properties and benefits of rituximab in the treatment of inflammatory diseases, the development and approval of biosimilars, and the potential benefits of rituximab biosimilars. PubMed and ClinicalTrials.gov databases were searched for "biosimilar" and "rituximab" and regulatory and pharmaceutical company web pages were screened regarding biosimilars in development and specific guidelines developed for the approval of biosimilars. The results indicate that, at present, six rituximab biosimilar candidates are undergoing comparative clinical development, and two were recently approved in the European Union. Our analysis indicates rituximab biosimilars are expected to have a continuing role in treating inflammatory conditions such as rheumatoid arthritis.

Biosimilar biologic drugs: a new frontier in medical care.

Physicians in training are expected to be aware of the newest developments in patient care. Biologic therapies have changed treatment of many diseases by specifically targeting key disease mediators, but patient access to these therapies can be limited. As patents for the first biologic therapies are expiring, the development and approval of products known as biosimilars is rapidly gaining momentum. A biosimilar is a biologic product that is highly similar to a reference product (a licensed biologic product), notwithstanding minor differences in clinically inactive components. Biosimilars undergo a thorough evaluation compared with the licensed biologic and need to demonstrate comparable clinical pharmacokinetics, efficacy, and safety including immunogenicity. Understanding the processes for new drug approvals, the rigorous evaluation of biosimilars, and considerations about their selection and use can help recently trained physicians to make informed treatment decisions and improve patient outcomes.

Patient attitudes and understanding about biosimilars: an international cross-sectional survey.

OBJECTIVE: To understand the levels of awareness, usage, and knowledge of biosimilars among patients, caregivers, and the general population in the US and the European Union; perceptions of biosimilars compared to originator biologics; perceived benefits and drawbacks of clinical trials; and whether advocacy groups impact patients' willingness to try a biosimilar. METHODS: An international survey was conducted which contained up to 56 closed-ended (requiring yes/no or ranking answers) and open-ended questions, depending on the population assigned. The survey was divided into distinct sections, including medication-class awareness, usage, and knowledge about biologic and biosimilar therapies; perceptions of clinical trials; and involvement in advocacy groups. Interviews were conducted in adults categorized as: 1) diagnosed: patients with inflammatory bowel disease including Crohn's disease and ulcerative colitis, rheumatoid arthritis, psoriasis, breast cancer, lung cancer, colorectal cancer, or non-Hodgkin's lymphoma; 2) diagnosed advocacy: individuals with these diseases who participated in patient support groups; 3) caregiver: has a loved one with these conditions and is involved in medical decisions; 4) general population: aged 18-64 years, without these conditions. Statistical analyses among groups within a region (US or EU) used column proportions test with a 95% confidence interval. RESULTS: In all, 3,198 individuals responded. Awareness about biologic therapies was significantly higher in diagnosed, diagnosed advocacy, and caregiver groups (45%-78%) versus general population (27%; P<0.05). Across all groups, awareness of biosimilars was low; only 6% of the general population reported at least a general impression of biosimilars. Awareness was significantly higher in the diagnosed advocacy group (20%-30%; P<0.05). Gaps in knowledge about biosimilars included safety, efficacy, and access to these agents. Respondents had generally positive perceptions of clinical trials, although barriers to participation were identified. CONCLUSION: An immediate need exists for patient education about biosimilars and clinical trials to ensure educated and informed decisions are made about biosimilar use.

Phase 1 study of anti-CTGF monoclonal antibody in patients with diabetes and microalbuminuria.

BACKGROUND AND OBJECTIVES: This report summarizes the first phase 1 trial treating patients with microalbuminuric diabetic kidney disease (DKD) using FG-3019, a human monoclonal antibody to connective tissue growth factor (CTGF). CTGF is critically involved in processes of progressive fibrosis, including DKD. This phase 1, open-label, dose-escalation trial evaluated safety, pharmacokinetics, and possible therapeutic effects of FG-3019 on albuminuria, proteinuria, and tubular proteins. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: Microalbuminuric subjects (n = 24) with type 2 (79%) or type 1 (21%) diabetes received 3 or 10 mg/kg FG-3019 dosed intravenously every 14 days for four doses. Albuminuria and safety follow-up were to days 62 and 365, respectively. RESULTS: No infusion was interrupted for symptoms, although 5 of 24 subjects had mild infusion-day adverse events thought to be possibly drug-related. No subject developed anti-FG-3019 antibodies. FG-3019 clearance was lower at 10 mg/kg than at 3 mg/kg, suggesting a saturable elimination pathway. Although this study was not designed for efficacy testing, it was notable that urinary albumin/creatinine ratio (ACR) decreased significantly from mean pretreatment ACR of 48 mg/g to mean post-treatment (day 56) ACR of 20 mg/g (P = 0.027) without evidence for a dose-response relationship. CONCLUSIONS: Treatment of microalbuminuric DKD subjects using FG-3019 was well tolerated and associated with a decrease in albuminuria. The data demonstrate a saturable pathway for drug elimination, minimal infusion adverse events, and no significant drug-attributable adverse effects over the year of follow-up. Changes in albuminuria were promising but require validation in a prospective, randomized, blinded study.

Prediction of clinical responses in a simulated phase III trial of Crohn's patients administered the antisense phosphorothioate oligonucleotide ISIS 2302: comparison of proposed dosing regimens.

ISIS 2302, an antisense phosphorothioate oligonucleotide (ODN) targeting human intercellular adhesion molecule-1 (ICAM-1) mRNA, is currently being evaluated for treatment of patients with Crohn's disease. From data collected in phase II clinical studies with ISIS 2302, validated population pharmacokinetic and exposure-response models were developed and used to simulate the plasma exposure and clinical response results for a proposed phase III trial design involving 100 patients treated with active drug and 50 patients treated with placebo. Simulated results of 1000 replications of the trial were calculated for various proposed dosing regimens. Overall, the simulated results indicated that a fixed dose regimen (250-400 mg, depending on patient sex and total body weight) given three times weekly provides both desirable ISIS 2302 plasma exposure and a high rate of clinical response in this patient population. However, the simulated results also suggest that inclusion of a larger number of patients than projected may be necessary to provide a desirable probability of study success (i.e., >80%), regarding demonstration of statistically significant differences between the active treatment and placebo groups for the primary clinical response measure (CCR rate).

Phase I trial of ISIS 104838, a 2'-methoxyethyl modified antisense oligonucleotide targeting tumor necrosis factor-alpha.

ISIS 104838 is a 20-mer phosphorothioate antisense oligonucleotide (ASO) that binds tumor necrosis factor-alpha (TNF-alpha) mRNA. It carries a 2'-methoxyethyl modification on the five 3' and 5' nucleotide sugars, with 10 central unmodified deoxynucleotides. ISIS 104838 was identified from a 264 ASO screen in phorbol myristate acetate-activated keratinocytes, and the dose response was assessed in lipopolysaccharide (LPS)-activated monocytes. Healthy males received multiple intravenous (i.v.) ISIS 104838 infusions in a placebo-controlled dose escalation trial (0.1-6 mg/kg). Additional volunteers received single or multiple subcutaneous (s.c.) injections. ISIS 104838 suppressed TNF-alpha protein by 85% in stimulated keratinocytes. The IC50 for TNF-alpha mRNA inhibition in stimulated monocytes was <1 microM. For i.v., C(max) occurred at the end of infusion. The effective plasma half-life was 15 to 45 min at 0.1 to 0.5 mg/kg and 1 to 1.8 h for higher doses. The apparent terminal plasma elimination half-life approximated 25 days. Obese subjects had higher plasma levels following equivalent mg/kg doses. For s.c. injections, C(max) occurred at 2 to 4 h and was lower than with equivalent i.v. dosing. Plasma bioavailability compared with i.v. was 82% following a 200 mg/ml s.c. injection. Transient activated partial thromboplastin time prolongation occurred after i.v. infusions and minimally after s.c. injections. Two subjects experienced rash, one a reversible platelet decrease, and mild injection site tenderness was noted. TNF-alpha production by peripheral blood leukocytes, induced ex vivo by LPS, was decreased by ISIS 104838 (p < 0.01). ISIS 104838, a second-generation antisense oligonucleotide, was generally well tolerated intravenously and subcutaneously. The pharmacokinetics support an infrequent dosing interval. Inhibition of TNF-alpha production ex vivo was demonstrated.