Proposing a framework to quantify the potential impact of pharmacokinetic drug-drug interactions caused by a new drug candidate by using real world data about the target patient population.

Drug development teams must evaluate the risk/benefit profile of new drug candidates that perpetrate drug-drug interactions (DDIs). Real-world data (RWD) can inform this decision. The purpose of this study was to develop a predicted impact score for DDIs perpetrated by three hypothetical drug candidates via CYP3A, CYP2D6, or CYP2C9 in type 2 diabetes mellitus (T2DM), obesity, or migraine. Optum Market Clarity was analyzed to estimate use of CYP3A, CYP2D6, or CYP2C9 substrates classified in the University of Washington Drug Interaction Database as moderate sensitive, sensitive, narrow therapeutic index, or QT prolongation. Scoring was based on prevalence of exposure to victim substrates and characteristics (age, polypharmacy, duration of exposure, and number of prescribers) of those exposed. The study population of 14,163,271 adults included 1,579,054 with T2DM, 3,117,753 with obesity, and 410,436 with migraine. For T2DM, 71.3% used CYP3A substrates, 44.3% used CYP2D6 substrates, and 44.3% used CYP2C9 substrates. For obesity, 57.1% used CYP3A substrates, 34.6% used CYP2D6 substrates, and 31.0% used CYP2C9 substrates. For migraine, 64.1% used CYP3A substrates, 44.0% used CYP2D6 substrates, and 28.9% used CYP2C9 substrates. In our analyses, the predicted DDI impact scores were highest for DDIs involving CYP3A, followed by CYP2D6, and CYP2C9 substrates, and highest for T2DM, followed by migraine, and obesity. Insights from RWD can be used to estimate a predicted DDI impact score for pharmacokinetic DDIs perpetrated by new drug candidates currently in development. This score can inform the risk/benefit profile of new drug candidates in a target patient population.

Multiple switching between the biosimilar adalimumab PF-06410293 and reference adalimumab in patients with active rheumatoid arthritis: a phase 3, open-label, randomised, parallel-group study.

BACKGROUND: An adalimumab biosimilar with an interchangeability designation could increase access to effective treatment for more patients. We aimed to assess the interchangeability of adalimumab biosimilar PF-06410293 (adalimumab-afzb) and reference adalimumab using a multi-switch study design. METHODS: We did an open-label, randomised, parallel-group study at 61 community (n=29), hospital (n=12), and academic (n=20) sites in ten countries (Bulgaria, Bosnia and Herzegovina, Czech Republic, Lithuania, Poland, Russia, Serbia, South Africa, Ukraine, and USA). Eligible patients were aged 18-70 years and met the 2010 American College of Rheumatology-European League Against Rheumatism classification criteria for rheumatoid arthritis for at least 4 months with moderately to severely active rheumatoid arthritis, based on their physician's evaluation. Eligible patients had been receiving methotrexate for at least 12 weeks and been on a stable dose for at least 4 weeks before the first dose of study medication. All patients received subcutaneous reference adalimumab (40 mg/0·4 mL [100 mg/mL] every 2 weeks) for 10 weeks before randomisation. At week 10, patients were randomly assigned (1:1) to either three switches between subcutaneous reference adalimumab (40 mg/0·4 mL [100 mg/mL] every 2 weeks) and adalimumab-afzb (40 mg/0·8 mL [50 mg/mL] every 2 weeks; switching group), or continuous dosing with subcutanous reference adalimumab (40 mg/0·4 mL [100 mg/mL] every 2 weeks; non-switching group) with stratification by bodyweight groups. Patients, investigators, and site personnel were not masked to treatment allocation. Primary endpoints were maximum observed serum concentration (Cmax) and area under plasma concentration-time curve (AUCτ) during weeks 30-32 in the pharmacokinetic population. Interchangeability was based on geometric mean ratios and corresponding 90% CIs within prespecified equivalence margins of 80-125% for both primary endpoints. Safety was analysed in all patients who received at least one dose of adalimumab-afzb or reference adalimumab. This trial is registered with ClinicalTrials.gov, NCT04230213. FINDINGS: Of the 569 patients assessed for eligibility between Jan 13, 2020, and June 22, 2021, 445 were enrolled, and 427 completed the first 10 weeks and were randomly assigned (213 to the switching group and 214 to the non-switching group). Participants had a median age of 56 years (IQR 46-63), 354 (83%) of 427 patients were women and 73 (17%) were men, and 422 (99%) were White. In the pharmacokinetic population (n=380), no clinically meaningful differences were observed in mean steady-state pharmacokinetic parameters between the switching and non-switching groups (geometric mean AUC 2237 µg × h/mL in the switching group and 2125 µg × h/mL in the non-switching group; Cmax 8·21 µg/mL in the switching group and 8·00 µg/mL in the non-switching group). Geometric mean ratios and 90% CIs for AUCτ (105·31, 89·16-124·39) and Cmax (102·56, 89·78-117·17) were within prespecified equivalence margins. No meaningful differences were observed in the proportion of patients who had serious adverse events (three [1%] of 213 patients in the switching group vs eight [4%] of 214 patients in the non-switching group), grade 3 or higher adverse events of special interest, discontinuations due to adverse events (eight [4%] vs nine [4%]), or immunogenic reactions in antidrug antibody-positive patients. No deaths were reported during the study. INTERPRETATION: The risk of multiple switches between reference adalimumab and adalimumab-afzb with respect to diminished efficacy (using pharmacokinetics as a surrogate) or safety is not greater than the risk of using reference adalimumab alone. FUNDING: Pfizer. VIDEO ABSTRACT.

Usability Study of PF-06410293, an Adalimumab Biosimilar, by Prefilled Pen: Open-Label, Single-Arm, Sub-Study of a Phase 3 Trial in Patients with Rheumatoid Arthritis.

INTRODUCTION: The aim of this sub-study was to evaluate injection success of patients with rheumatoid arthritis (RA) and their caregivers administering the adalimumab (ADL) biosimilar, PF-06410293 (ADL-PF: adalimumab-afzb; Abrilada®/Amsparity®/Xilbrilada®) by prefilled pen (PFP) during the open-label treatment period in year two (weeks 52-78) of a phase 3 multinational, double-blind, clinical study (NCT02480153) comparing ADL-PF and reference ADL (Humira®) sourced from the EU. METHODS: This sub-study included adult patients with active RA not adequately controlled by methotrexate. Patients received subcutaneous ADL-PF 40 mg by prefilled syringe (PFS) at weeks 52 and 54, then six biweekly doses (weeks 56-66) of ADL-PF 40 mg each via a single-use PFP device. Training was given on first injection at week 56; all injections were given by patients/caregivers. The primary endpoint was delivery system success rate (DSSR): the percentage of participants (i.e., actual PFP user) achieving delivery success for each of the six attempted PFP injections. Injection success was recorded by the observer (Observer Assessment Tool) and participant (Participant Assessment Tool). RESULTS: In total, 50 patients with no experience self-injecting with an autoinjector/injection pen were included (74.0% female; mean age at screening, 54.9 years; mean RA duration, 8.0 years). Of these, 49 (98.0%) completed the sub-study and 46 (92.0%) received all six PFP injections. Overall DSSR (n = 294 injections) across visits was 100% (95% CI 92.0-100.0%). Complete injection was confirmed following inspection of 292 used and returned PFPs. A total of 47/49 (95.9%) participants who completed the sub-study elected to continue study treatment using PFP injections, rather than switching back to the PFS. CONCLUSIONS: All actual PFP users could safely and effectively administer ADL-PF by PFP at each visit, and nearly all participants who completed the sub-study elected to continue study treatment using PFP injections. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02480153; EudraCT number: 2014-000352-29.

Long-term efficacy, safety, and immunogenicity of the adalimumab biosimilar, PF-06410293, in patients with rheumatoid arthritis after switching from reference adalimumab (Humira®) or continuing biosimilar therapy: week 52-92 data from a randomized, double-blind, phase 3 trial.

BACKGROUND/OBJECTIVE: REFLECTIONS B538-02 is a randomized, double-blind comparative study of the adalimumab (ADL) biosimilar PF-06410293, (ADL-PF), and reference ADL sourced from the European Union (ADL-EU) in patients with active RA. Therapeutic equivalence was demonstrated based on ACR20 responses at week 12 (primary endpoint). We report long-term safety, immunogenicity, and efficacy of ADL-PF in patients who continued ADL-PF treatment throughout 78 weeks or who switched from ADL-EU to ADL-PF at week 26 or week 52. METHODS: Eligible patients (2010 ACR/EULAR RA diagnosis criteria for ≥ 4 months; inadequate response to MTX, ≤ 2 doses non-ADL biologic), stratified by geographic regions were initially randomized (1:1) in treatment period 1 (TP1) to ADL-PF or ADL-EU (40 mg subcutaneously, biweekly), both with MTX (10-25 mg/week). At week 26 (start of TP2), patients receiving ADL-EU were re-randomized to remain on ADL-EU or transition to ADL-PF for 26 weeks. At week 52 (start of TP3), all patients received open-label treatment with ADL-PF for 26 weeks and were followed after last treatment dose to week 92. To evaluate maintenance of response after switching or remaining on ADL-PF, ACR20, DAS28-4(CRP), and other measures of clinical response/remission were assessed through week 78 as secondary endpoints. Three groups were evaluated: biosimilar, week 26 switch, and week 52 switch. RESULTS: Overall, 507 patients participated in TP3. ACR20 response rates at week 52 were 88.4%, 88.2%, and 87.6% for the biosimilar, week 26, and week 52 switch groups, respectively. ACR20 response rates and DAS28-4(CRP) scores were sustained and comparable across groups in TP3. Incidence of treatment-emergent adverse events (AEs) during TP3 and follow-up was 42.6% (biosimilar), 37.0% (week 26 switch), and 50.8% (week 52 switch); 3 (0.6%) patients (all week 52 switch) reported treatment-related serious AEs. ADL-PF was generally well tolerated, with a comparable safety profile across groups. Overall, incidences of patients with anti-drug antibodies in TP3 and follow-up were comparable among groups (46.1%, 46.5%, and 54.2%, respectively). CONCLUSIONS: There were no clinically meaningful differences in safety, immunogenicity, and efficacy for patients who were maintained on ADL-PF for 78 weeks and those who had switched from ADL-EU at week 26 or week 52. TRIAL REGISTRATION: ClinicalTrials.gov , NCT02480153. First posted on June 24, 2015; EU Clinical Trials Register; EudraCT number: 2014-000352-29. Start date, October 27, 2014.

Randomised study of PF-06410293, an adalimumab (ADL) biosimilar, compared with reference ADL for the treatment of active rheumatoid arthritis: results from weeks 26-52, including a treatment switch from reference ADL to PF-06410293.

OBJECTIVE: To investigate the efficacy, safety, immunogenicity and pharmacokinetics of biosimilar adalimumab (ADL) PF-06410293 (ADL-PF; adalimumab-afzb) versus EU-sourced reference ADL (ADL-EU) in patients with active rheumatoid arthritis (RA) on longer-term treatment and after being switched from ADL-EU to ADL-PF. METHODS: In this multinational, double-blind study, patients with active RA were initially randomised to ADL-PF or ADL-EU for 26 weeks (treatment period (TP) 1). At the start of TP2 (weeks 26-52), patients in the ADL-EU arm were blindly re-randomised 1:1 to remain on ADL-EU (ADL-EU/ADL-EU; n=135) or switched to ADL-PF (ADL-EU/ADL-PF; n=134); patients receiving ADL-PF continued blinded treatment (ADL-PF/ADL-PF; n=283). RESULTS: The American College of Rheumatology 20% improvement (ACR20) response rates were comparable between treatment groups at all visits during TP2. At week 52, ACR20 response rates were 82.7% (ADL-PF/ADL-PF), 79.3% (ADL-EU/ADL-EU) and 84.3% (ADL-EU/ADL-PF). Other measures of deep response (ACR50/70, ACR/EULAR-defined remission, EULAR good response, and Disease Activity Score in 28 Joints Based on High-Sensitivity C-Reactive Protein <2.6) and Health Assessment Questionnaire-Disability Index were maintained over TP2 and comparable between groups. Treatment-emergent adverse events were reported in 43.5% (ADL-PF/ADL-PF), 44.4% (ADL-EU/ADL-EU) and 38.3% (ADL-EU/ADL-PF) of patients; there were no clinically meaningful differences in the safety profiles between groups. The percentage of patients who were antidrug antibody positive was comparable overall among ADL-PF/ADL-PF (47.3%), ADL-EU/ADL-EU (54.1%) and ADL-EU/ADL-PF (45.9%). CONCLUSIONS: The similar efficacy, safety, immunogenicity and pharmacokinetics of ADL-PF and ADL-EU, maintained up to week 52, were unaffected by blinded treatment switch from ADL-EU to ADL-PF at week 26. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier: NCT02480153; EudraCT number: 2014-000352-29.

Randomized, Open-Label, Single-Dose, Parallel-Group Pharmacokinetic Study of PF-06410293 (adalimumab-afzb), an Adalimumab Biosimilar, by Subcutaneous Dosing Using a Prefilled Syringe or a Prefilled Pen in Healthy Subjects.

This open-label, single-dose, randomized, parallel-group, 2-arm phase 1 bioequivalence (BE) study assessed the pharmacokinetics (PK), safety, and tolerability of PF-06410293 (ADL-PF), an adalimumab (ADL) biosimilar, following administration by prefilled pen (PFP) or prefilled syringe (PFS). A total of 164 healthy adult subjects were randomized (1:1) to receive ADL-PF (40 mg subcutaneously) in the lower abdomen or upper anterior thigh by PFS or PFP; 163 subjects were included in the primary PK analysis. The concentration-time profiles of the ADL-PF PFS and PFP treatment arms were similar. The 90% confidence intervals for the test/reference ratios of the primary end points (area under the serum concentration-time profile from time 0 to 2 weeks after dosing and maximum observed serum concentration) fell within the 80.00%-125.00% prespecified margin for BE. Comparable numbers of subjects experienced adverse events (AEs) between treatment groups, and injection-site pain was similar at all times and for the 2 injection-site locations. This study demonstrated the BE of ADL-PF following subcutaneous administration using either a PFS or PFP device. ADL-PF by PFS or PFP injection was well tolerated, with the distribution of AEs, including injection-site reactions, being similar between treatment arms.

Interchangeability of Biosimilars: What Level of Clinical Evidence is Needed to Support the Interchangeability Designation in the United States?

A biosimilar is a biologic drug that is "highly similar to a reference (originator) product, with no clinically meaningful differences between the two products in safety, purity, and potency". Regulatory approval of a biosimilar is based on analytical, structural, and functional comparisons with the reference product, comparative nonclinical (in vivo) studies, clinical pharmacokinetics and/or pharmacodynamics, and immunogenicity. In addition, comparative clinical efficacy and safety assessments are usually conducted and, taken together, comprise the "totality of the evidence" supporting biosimilarity. For a biosimilar to meet the additional designation of interchangeability in the United States (US), the applicant must demonstrate that the biological drug can be expected to produce the "same clinical result as the reference product in any given patient" and "if the biological drug is administered more than once to an individual, the risk in terms of safety or diminished efficacy of alternating or switching between the use of the biological drug and the reference product is no greater than the risk of using the reference product without such alternation or switch". The challenges faced in conducting clinical studies to support a designation of interchangeability, as defined in the final interchangeability guidance from the US Food and Drug Administration, are considered. Potential alternative approaches to generating adequate and sufficient clinical data to support a designation of interchangeability are also presented.

Long-term Efficacy, Safety, and Immunogenicity of the Infliximab (IFX) Biosimilar, PF-06438179/GP1111, in Patients with Rheumatoid Arthritis After Switching from Reference IFX or Continuing Biosimilar Therapy: Week 54-78 Data From a Randomized, Double-Blind, Phase III Trial.

OBJECTIVE: Our objective was to evaluate the long-term efficacy, safety, and immunogenicity of the infliximab biosimilar, PF-06438179/GP1111 (PF-SZ-IFX), in patients with rheumatoid arthritis (RA) who continued biosimilar treatment throughout 78 weeks or who switched from reference infliximab (Remicade®) sourced from the EU (IFX-EU) at week 30 or week 54 in the REFLECTIONS B537-02 study. METHODS: In this phase III, double-blind, active-controlled study, patients with moderate-to-severe active RA were initially randomized to PF-SZ-IFX or IFX-EU, each with methotrexate (treatment period [TP] 1; N = 650). At week 30, patients receiving PF-SZ-IFX continued PF-SZ-IFX; patients receiving IFX-EU were re-randomized to continue IFX-EU or switch to PF-SZ-IFX (TP2; n = 566). From weeks 54 to 78, all patients received open-label treatment with PF-SZ-IFX (TP3; n = 505). Efficacy, safety, and immunogenicity data were analyzed during TP3. RESULTS: Efficacy was sustained and comparable across groups at week 78, with American College of Rheumatology criteria for ≥ 20% clinical improvement response rates of 75.9% (biosimilar group), 77.8% (week 30 switch group), and 68.3% (week 54 switch group). The incidence of treatment-emergent adverse events was 28.9%, 29.4%, and 30.2%, respectively. The proportion of patients who were antidrug antibody (ADA) positive and neutralizing antibody positive (as a percentage of ADA-positive patients) was stable and comparable between groups. CONCLUSIONS: Results to week 78 continue to support the efficacy, safety, and immunogenicity of PF-SZ-IFX in patients with moderate-to-severe active RA. There were no clinically meaningful differences between groups, independent of a single treatment transition from IFX-EU to PF-SZ-IFX at week 30 or week 54. TRIAL REGISTRATION NUMBER: NCT02222493.

Population pharmacokinetic modeling of PF-06439535 (a bevacizumab biosimilar) and reference bevacizumab (Avastin®) in patients with advanced non-squamous non-small cell lung cancer.

PURPOSE: The objectives of this analysis were to characterize the population pharmacokinetics (PK) of PF-06439535 (a bevacizumab biosimilar) and reference bevacizumab (Avastin®) sourced from the European Union (bevacizumab-EU) in patients with advanced non-squamous non-small cell lung cancer (NSCLC), and to quantify the difference in PK parameters between the two drug products via covariate analysis. METHODS: Pooled PF-06439535 and bevacizumab-EU serum concentration data from a comparative clinical efficacy and safety study (NCT02364999) in patients with NSCLC (N = 719) were analyzed using a non-linear mixed-effects modeling approach. Patients received PF-06439535 plus chemotherapy or bevacizumab-EU plus chemotherapy every 21 days for 4-6 cycles, followed by monotherapy with PF-06439535 or bevacizumab-EU. PF-06439535 or bevacizumab-EU was administered intravenously at a dose of 15 mg/kg. Effects of patient and disease covariates, as well as the drug product (PF-06439535 versus bevacizumab-EU), on PK were investigated. RESULTS: Overall, 8632 serum bevacizumab concentrations from 351 patients in the PF-06439535 group and 354 patients in the bevacizumab-EU group were included in the analysis. A two-compartment model adequately described the combined data. Clearance (CL) and central volume of distribution (V1) estimates were 0.0113 L/h and 2.99 L for a typical 71-kg female patient with NSCLC administered bevacizumab-EU. CL and V1 increased with body weight and were higher in males than females even after accounting for differences in body weight. The 95% confidence intervals for the effect of drug product on CL and V1 encompassed unity. CONCLUSIONS: The population PK of PF-06439535 and bevacizumab-EU were well characterized by a two-compartment model. Covariate analysis did not reveal any appreciable differences between PK parameters for PF-06439535 and bevacizumab-EU in patients with NSCLC. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02364999.

Randomised, double-blind, phase III study comparing the infliximab biosimilar, PF-06438179/GP1111, with reference infliximab: efficacy, safety and immunogenicity from week 30 to week 54.

Objective: To investigate the efficacy, safety and immunogenicity of PF-06438179/GP1111 (PF-SZ-IFX) compared with European reference infliximab (Remicade®; ref-IFX) in patients with moderate-to-severe, active rheumatoid arthritis after continued long-term use of PF-SZ-IFX, and in patients who were switched from ref-IFX to PF-SZ-IFX. Methods: REFLECTIONS B537-02 was a double-blind, active-controlled, multinational study in which patients (N=650) were initially randomised to PF-SZ-IFX or ref-IFX for 30 weeks (treatment period [TP] 1). During weeks 30-54 (TP2), the PF-SZ-IFX group (n=280) continued treatment with PF-SZ-IFX (PF-SZ-IFX/PF-SZ-IFX) and patients in the ref-IFX group (n=286) were rerandomised (1:1) to continue ref-IFX (ref-IFX/ref-IFX) (n=143) or switch to PF-SZ-IFX (ref-IFX/PF-SZ-IFX) (n=143) for a further 24 weeks. Efficacy, safety, immunogenicity and pharmacokinetics were evaluated. Results: During TP2, patients in all three treatment groups continued to maintain comparable treatment response. At week 54, the American College of Rheumatology (ACR20) response rates were 71.1% (PF-SZ-IFX/PF-SZ-IFX), 64.3% (ref-IFX/ref-IFX) and 70.6% (ref-IFX/PF-SZ-IFX). Observations for other endpoints, including ACR50/70, Disease Activity Score in 28 Joints Based on High-Sensitivity C Reactive Protein(DAS28-CRP) remission, and mean change in DAS28-CRP and Health Assessment Questionnaire-Disability Index, were also comparable. Treatment-emergent adverse events were reported in 36.8% (PF-SZ-IFX/PF-SZ-IFX), 33.6% (ref-IFX/ref-IFX) and 37.8% (ref-IFX/PF-SZ-IFX) of patients; there were no clinically meaningful differences in the safety profiles between groups. The percentage of patients who were antidrug antibody-positive was generally stable through the treatment period and comparable overall between the PF-SZ-IFX/PF-SZ-IFX (52.1%; neutralising: 80.8%), ref-IFX/ref-IFX (60.1%; neutralising: 84.9%) and ref-IFX/PF-SZ-IFX (58.0%; neutralising 78.3%) groups. Conclusions: The similar efficacy, safety and immunogenicity of PF-SZ-IFX compared with ref-IFX were maintained for up to 54 weeks and were not affected by blinded treatment switch from ref-IFX to PF-SZ-IFX at week 30. Trial registration number: NCT02222493.

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.

Extension Study of PF-05280586, a Potential Rituximab Biosimilar, Versus Rituximab in Subjects With Active Rheumatoid Arthritis.

OBJECTIVE: This extension study provided continued treatment to subjects with active rheumatoid arthritis who had participated for ≥16 weeks in a pharmacokinetic similarity study of PF-05280586 (potential rituximab biosimilar). Objectives were to evaluate overall pharmacokinetics, pharmacodynamics, immunogenicity, safety, and tolerability of PF-05280586 after transition from rituximab reference products to PF-05280586, and follow-up of biomarker and efficacy assessments. METHODS: Subjects were offered ≤3 additional courses of treatment of PF-05280586, with or without a single transition from rituximab in Europe (rituximab-EU; MabThera) or the US (rituximab-US; Rituxan) to PF-05280586. Each course comprised 2 intravenous infusions (1,000 mg on days 1 and 15, separated by 24 weeks [± 8 weeks]). RESULTS: Of 220 subjects in the parent study, 185 were randomized and included in this study. There were no notable differences in drug concentrations between groups or across courses, with little variation in depletion of CD19+ B cells between groups, and no apparent relationship between infusion-related reactions and antidrug antibodies with or without single transition from rituximab reference products to PF-05280586. Long-term safety and tolerability of PF-05280586 was acceptable in all groups for up to 96 weeks, with a low incidence of treatment-emergent adverse events independent of single drug transition. The percentage of subjects with a low disease activity score and disease activity score remission was similar across groups for all time points, and responses were sustained until end of study. CONCLUSION: This study demonstrated acceptable safety, tolerability, and immunogenicity, with or without single transition from rituximab reference products to PF-05280586, without increased immunogenicity on single transition.

Multiple-dose ponezumab for mild-to-moderate Alzheimer's disease: Safety and efficacy.

INTRODUCTION: Multiple intravenous doses of ponezumab, an anti-amyloid antibody, were evaluated in subjects with mild-to-moderate Alzheimer's disease (AD). METHODS: In part A, 77 subjects were randomized to ponezumab 0.1, 0.5, or 1 mg/kg (75 treated) and 26 to placebo (24 treated). In part B, 63 subjects were randomized and treated with ponezumab 3 or 8.5 mg/kg and 32 with placebo. Subjects received 10 infusions over 18 months and were followed for 6 months thereafter. RESULTS: Ponezumab was generally safe and well tolerated. Most common adverse events were fall (16.7% ponezumab, 21.4% placebo), headache (13.8%, 21.4%), and cerebral microhemorrhage (13.8%, 19.6%). Plasma ponezumab increased dose-dependently with limited accumulation. Cerebrospinal fluid penetration was low. Plasma Aß1-x and Aß1-40 showed robust increases, but cerebrospinal fluid biomarkers showed no dose response. Ponezumab had no effects on cognitive/functional outcomes or brain volume. CONCLUSIONS: Multiple-dose ponezumab was generally safe, but not efficacious, in mild-to-moderate AD.

Ponezumab in mild-to-moderate Alzheimer's disease: Randomized phase II PET-PIB study.

INTRODUCTION: The safety, pharmacokinetics, and effect on peripheral and central amyloid ß (Aß) of multiple doses of ponezumab, an anti-Aß monoclonal antibody, were characterized in subjects with mild-to-moderate Alzheimer's disease treated for 1 year. METHODS: Subjects were aged ≥50 years with Mini-Mental State Examination scores 16 to 26. Cohort Q was randomized to ponezumab 10 mg/kg (n = 12) or placebo (n = 6) quarterly. Cohort M was randomized to a loading dose of ponezumab 10 mg/kg or placebo, followed by monthly ponezumab 7.5 mg/kg (n = 12) or placebo (n = 6), respectively. RESULTS: Ponezumab was generally well tolerated. Plasma concentrations increased dose dependently, but cerebrospinal fluid (CSF) penetration was low. Plasma Aß increased dose dependently with ponezumab, but CSF biomarkers, brain amyloid burden, cognition, and function were not affected. CONCLUSIONS: Both ponezumab dosing schedules were generally safe and well tolerated but did not alter CSF biomarkers, brain amyloid burden, or clinical outcomes.

Safety and pharmacokinetics of PF-04360365 following a single-dose intravenous infusion in Japanese subjects with mild-to-moderate Alzheimer's disease: a multicenter, randomized, double-blind, placebo-controlled, dose-escalation study.

OBJECTIVE: PF-04360365 is a humanized IgG(2)Δa anti-amyloid ß (Aß) antibody designed to improve outcome in Alzheimer's disease (AD). Single doses of 0.1 - 10 mg/kg were safe and well tolerated in Western (mostly Caucasian) subjects with mild-to-moderate AD. This Phase 1, multicenter, randomized, double-blind, dose-escalation study was the first to evaluate the safety, pharmacokinetics, pharmacodynamics, and immunogenicity of PF-04360365 in Japanese subjects. MATERIALS AND METHODS: 30 subjects with mild-to-moderate AD were enrolled. In each cohort, 3 subjects received PF-04360365 (0.1, 0.5, 1, 5, or 10 mg/kg) and 1 subject received placebo as a single 2-hour intravenous infusion. Subjects were monitored as inpatients for 24 hours and then as outpatients for 1 year. RESULTS: All subjects completed the study. There were no serious or National Cancer Institute Common Terminology Criteria for Adverse Events grade ≥ 3 adverse events, hypersensitivity reactions, or antidrug antibodies. No clinical or MRI evidence of brain microhemorrhage, cerebral edema, or encephalitis was observed. PF-04360365 plasma concentrations increased with dose, and pharmacokinetics were consistent with a small steady-state volume of distribution, slow clearance, and long elimination half-life. Cerebrospinal fluid (CSF):plasma ratios were < 0.5%. Plasma Aß species showed dose-dependent increases in C(max) and AUC(∞), but CSF biomarkers did not differ clearly between treatment arms. CONCLUSIONS: PF-04360365 was safe and well tolerated in Japanese subjects. Pharmacokinetics and plasma pharmacodynamic responses in Japanese subjects were comparable to those in Western subjects. *No longer affiliated with Pfizer.

How current understanding of clearance mechanisms and pharmacodynamics of therapeutic proteins can be applied for evaluation of their drug-drug interaction potential.

Increasing use of therapeutic proteins (TPs) in polypharmacy settings calls for more in-depth understanding of the biological interactions that can lead to increased toxicity or loss of pharmacological effect. Factors such as patient population, medications that are likely to be coadministered in that population, clearance mechanisms of a TP, and concomitant drugs have to be taken into account to determine the potential for drug-drug interactions (DDIs). The most well documented TP DDI mechanism involves cytokine-mediated changes in drug-metabolizing enzymes. Because of the limitations of the current preclinical models for addressing this type of DDI, clinical evaluation is currently the most reliable approach. Other DDI mechanisms need to be addressed on a case-by-case basis. These include altered clearance of TPs resulting from the changes in the target protein levels by the concomitant medication, displacement of TPs from binding proteins, modulation of Fcγ receptor expression, and others. The purpose of this review is to introduce the approach used by Pfizer scientists for evaluation of the DDI potential of novel TP products during drug discovery and development.

Population pharmacokinetic analysis of carboxyhaemoglobin concentrations in adult cigarette smokers.

AIMS: To develop a population-based model to describe and predict the pharmacokinetics of carboxyhaemoglobin (COHb) in adult smokers. METHODS: Data from smokers of different conventional cigarettes (CC) in three open-label, randomized studies were analysed using NONMEM (version V, Level 1.1). COHb concentrations were determined at baseline for two cigarettes [Federal Trade Commission (FTC) tar 11 mg; CC1, or FTC tar 6 mg; CC2]. On day 1, subjects were randomized to continue smoking their original cigarettes, switch to a different cigarette (FTC tar 1 mg; CC3), or stop smoking. COHb concentrations were measured at baseline and on days 3 and 8 after randomization. Each cigarette was treated as a unit dose assuming a linear relationship between the number of cigarettes smoked and measured COHb percent saturation. Model building used standard methods. Model performance was evaluated using nonparametric bootstrapping and predictive checks. RESULTS: The data were described by a two-compartment model with zero-order input and first-order elimination with endogenous COHb. Model parameters included elimination rate constant (k(10)), central volume of distribution (Vc/F), rate constants between central and peripheral compartments (k(12) and k(21)), baseline COHb concentrations (c0), and relative fraction of carbon monoxide absorbed (F1). The median (range) COHb half-lives were 1.6 h (0.680-2.76) and 30.9 h (7.13-367) (alpha and beta phases, respectively). F1 increased with increasing cigarette tar content and age, whereas k(12) increased with ideal body weight. CONCLUSION: A robust model was developed to predict COHb concentrations in adult smokers and to determine optimum COHb sampling times in future studies.