ABSTRACT
OBJECTIVES: We aimed to identify transcriptional gene signatures predictive of clinical response, for pharmacodynamic evaluation, and to provide mechanistic insight into JNJ-55920839, a human IgG1κ neutralizing mAb targeting IFN-α/IFN-ω, in participants with systemic lupus erythematosus (SLE). METHODS: Blood samples were obtained from SLE participants at baseline and up to Day 130, who received six 10 mg/kg IV doses of JNJ-55920839/placebo every 2 weeks. Participants with mild-to-moderate SLE who achieved clinical responses using SLE Disease Activity Index 2000 Responder Index 4-point change were considered responders. Transcriptional signatures from longitudinally collected blood were generated by RNA-Seq; signatures were generated by microarray from baseline blood samples exposed in vitro to JNJ-55920839 versus untreated. RESULTS: Two gene signatures (IFN-I Signaling and Immunoglobulin Immune Response) exhibited pharmacodynamic changes among JNJ-55920839 responders. The Immunoglobulin signature, but not the IFN-I signature, was elevated at baseline in JNJ-55920839 responders. A gene cluster associated with neutrophil-mediated immunity was reduced at baseline in JNJ-55920839 responders, substantiated by lower neutrophil counts in responders. An IFN-I signature was suppressed by JNJ-55920839 in vitro treatment versus untreated blood to a greater extent in responders before in vivo dosing. CONCLUSIONS: These signatures may enable enrichment for treatment responders when using IFN-I-suppressing treatments in SLE.
Subject(s)
Antibodies, Monoclonal, Humanized/pharmacology , Interferon-alpha/antagonists & inhibitors , Lupus Erythematosus, Systemic/drug therapy , Administration, Intravenous , Adult , Aged , Antibodies, Monoclonal, Humanized/administration & dosage , Antibodies, Monoclonal, Humanized/therapeutic use , Biomarkers/blood , Case-Control Studies , Female , Humans , Immunoglobulins/genetics , Immunoglobulins/immunology , Interferon Type I/drug effects , Interferon Type I/genetics , Interferon-alpha/genetics , Interferon-alpha/immunology , Lupus Erythematosus, Systemic/blood , Lupus Erythematosus, Systemic/genetics , Male , Middle Aged , Placebos/administration & dosage , Severity of Illness Index , Transcription, Genetic/genetics , Transcriptome/drug effects , Transcriptome/genetics , Ustekinumab/administration & dosage , Ustekinumab/pharmacology , Ustekinumab/therapeutic useABSTRACT
BACKGROUND: The interferon (IFN) pathway has been correlated with clinical and serological markers of disease activity in patients with systemic lupus erythematosus (SLE). OBJECTIVE: The pharmacokinetics and pharmacodynamics of JNJ-55920839, a fully human immunoglobulin G1κ antibody targeting IFNα/ω, were investigated. METHODS: In a double-blind, first-in-human study, Part A enrolled 48 healthy adults who received a single dose of placebo/JNJ-55920839 between 0.3 and 15 mg/kg intravenous (IV) or at 1 mg/kg subcutaneous (SC). Part B enrolled 26 adults with SLE who received placebo or JNJ-55920839 10 mg/kg IV 6 times biweekly. Pharmacokinetic parameters were calculated by noncompartmental analysis (NCA) and estimated by nonlinear mixed-effects modeling. RESULTS: JNJ-55920839 pharmacokinetics following a single IV infusion exhibited a biphasic disposition in healthy subjects. Maximum plasma concentration (Cmax) and area under the concentration-time curve values increased dose-proportionally. Mean clearance (CL) after a single IV infusion ranged between 2.28 and 3.09 mL/kg/day. Absolute bioavailability after a single SC injection was ≥ 80.0%. Mean terminal elimination half-life (t1/2) was similar after IV (20.7 to 24.6 days) and SC administration (22.6 days). Steady state of JNJ-55920839 was achieved 6 weeks after multiple 10 mg/kg IV doses in subjects with SLE. Mean steady-state CL and t1/2 were 4.73 mL/kg/day and 14.8 days, respectively. A linear 2-compartment population pharmacokinetic model with 1st-order absorption and elimination adequately characterized the pharmacokinetics; parameters were consistent with NCA estimates. Higher CL was estimated in subjects with SLE compared with healthy subjects, after correcting for body weight. A trend of increased total IFNα/ω levels was observed after treatment with JNJ-55920839. CONCLUSION: Pharmacokinetic and pharmacodynamic analyses of the data from this study demonstrated that there was biphasic disposition in both healthy subjects and subjects with SLE, CL was faster in subjects with SLE, and increases in total IFNα/ω levels were observed in both healthy subjects and subjects with SLE after treatment with JNJ-55920839, thus further development is supported. The study is registered at ClinicalTrials.gov NCT02609789.
Subject(s)
Antibodies, Monoclonal, Humanized , Interferon-alpha/antagonists & inhibitors , Lupus Erythematosus, Systemic/drug therapy , Administration, Intravenous , Adult , Antibodies, Monoclonal, Humanized/pharmacokinetics , Antibodies, Monoclonal, Humanized/pharmacology , Antibodies, Monoclonal, Humanized/therapeutic use , Area Under Curve , Biological Availability , Double-Blind Method , Female , Healthy Volunteers , Humans , Infusions, Intravenous , Injections, Subcutaneous , Male , Middle Aged , PlacebosABSTRACT
BACKGROUND: Activation of the type I interferon (IFN) pathway is associated with systemic lupus erythematosus (SLE). We assessed the safety and tolerability of JNJ-55920839, a human monoclonal antibody that selectively neutralises most human IFNα subtypes and IFNω, in healthy participants and those with SLE. METHODS: This was a two-part, first-in-human, phase 1, randomised, double-blind, placebo-controlled, multicentre study of single-ascending intravenous doses of 0·3-15 mg/kg or a single subcutaneous dose of 1 mg/kg JNJ-55920839 administered to healthy participants (part A) and multiple intravenous doses of 10 mg/kg JNJ-55920839 administered to participants with SLE (part B). Healthy men and women (women had to be postmenopausal or surgically sterile) aged 18-55 years; bodyweight of 50-90 kg; and body-mass index (BMI) of 18-30 kg/m2 were eligible for inclusion in part A. Men and women with SLE were recruited to part B, fertile female participants were required to have a negative pregnancy test result before and during the study and be using two highly effective methods of birth control. The inclusion criteria for participants with SLE in part B matched part A, except for bodyweight (40-100 kg). In both parts, participants were randomly assigned (3:1) to receive JNJ-55920839 or placebo; a computer-generated randomisation schedule was used in part A, and randomisation was stratified by racial and ethnic subpopulation and elevated levels of serological disease activity in part B. The primary outcome was evaluation of safety and tolerability of the study regimen assessed using clinical and laboratory tests compared with placebo. This study is registered with ClinicalTrials.gov, NCT02609789. FINDINGS: Between Dec 11, 2015, and Sept 20, 2018, 48 healthy participants from a single site and 28 participants with mild-to-moderate SLE from 19 participating centres in seven countries were enrolled in the study. 12 healthy volunteers in part A and eight participants with SLE in part B received placebo. The most common treatment-emergent adverse events in both part A and B were in the system organ class of infections and infestations with a higher percentage of participants administered JNJ-55920839 with infections (ten [28%] of 36 in part A and nine [50%] of 18 in part B) than those exposed to placebo (two [17%] of 12 in part A and one [13%] of eight in part B). Particpants in part B were permitted to continue on defined ongoing standard of care medications. In two participants with SLE, locally disseminated herpes zoster of the skin was reported. No other clinically significant safety or tolerability issues were identified beyond the infections observed in participants treated with JNJ-55920839. INTERPRETATION: JNJ-55920839 was well tolerated and safe. Additional studies are warranted to determine optimal dosing of patients and further explore safety. FUNDING: Janssen.
ABSTRACT
PURPOSE: The purpose of this study is to evaluate the pharmacokinetics, immunogenicity, safety, and tolerability of guselkumab, a human monoclonal antibody with high affinity and specificity for binding to interleukin-23. METHODS: In this first-in-human, phase 1, randomized study, a single intravenous (IV; 0.03-10 mg/kg) or subcutaneous (SC; 10-300 mg) dose of guselkumab was administered to 47 healthy subjects, and a single SC dose (placebo, 10, 30, 100, 300 mg) was administered to 24 patients with moderate-to-severe psoriasis. RESULTS: Mean maximum observed serum concentration and area under the zero-to-infinity serum concentration-time curve of guselkumab increased in an approximately dose-proportional manner over the dose range of 0.03-10 mg/kg following a single IV administration or 10-300 mg following a single SC administration. Mean clearance and volume of distribution ranged from 3.62-6.03 mL/day/kg and 99.38-123.22 mL/kg, respectively. Mean half-life ranged from 12 to 19 days in healthy subjects and patients with psoriasis. Among guselkumab-treated subjects/patients, 1/30 (3.3 %) healthy subjects in the IV group, 0/6 healthy subjects in the SC group, and 1/20 (5.0 %) patients with psoriasis tested positive for antibodies to guselkumab. No clinically significant adverse events were identified in this study. CONCLUSION: Guselkumab pharmacokinetic profiles were generally comparable between healthy subjects and patients with psoriasis. Guselkumab, administered as an IV infusion or SC injection, was well tolerated in healthy subjects and patients with psoriasis.
Subject(s)
Antibodies, Monoclonal/pharmacokinetics , Dermatologic Agents/pharmacokinetics , Adolescent , Adult , Aged , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal/blood , Antibodies, Monoclonal, Humanized , Area Under Curve , Dermatologic Agents/administration & dosage , Dermatologic Agents/adverse effects , Dermatologic Agents/blood , Double-Blind Method , Female , Half-Life , Healthy Volunteers , Humans , Infusions, Intravenous , Injections, Subcutaneous , Interleukin-23/antagonists & inhibitors , Interleukin-23/immunology , Male , Middle Aged , Psoriasis/blood , Psoriasis/drug therapy , Psoriasis/metabolism , Young AdultABSTRACT
This therapeutic protein-drug interaction study evaluated the disease-mediated effect of sirukumab (anti-interleukin 6 [anti-IL-6] monoclonal antibody) on the pharmacokinetics of the cytochrome P450 (CYP) probe substrates midazolam (CYP3A), omeprazole (CYP2C19), warfarin (CYP2C9), and caffeine (CYP1A2) in patients with active rheumatoid arthritis (RA). Twelve patients with C-reactive protein (CRP) ≥ 8.0 mg/L at screening received oral administration of a CYP probe cocktail consisting of 0.03 mg/kg midazolam, 10 mg warfarin + 10 mg vitamin K (equivalent to 5 mg S-warfarin), 20 mg omeprazole, and 100 mg caffeine 1 week before and 1, 3, and 6 weeks after a single subcutaneous dose of 300 mg sirukumab. The results showed that the pharmacokinetics of midazolam, omeprazole, and S-warfarin were nonequivalent before and after the administration of a single dose of 300 mg sirukumab. Area under the plasma concentration-time curve (AUC0- ∞ ) for midazolam, omeprazole, and S-warfarin was reduced by 30%-35%, 37%-45%, and 18%-19%, respectively, after sirukumab administration. Caffeine AUC0-∞ was increased by 20%-34% after sirukumab administration. The effect of sirukumab on CYP substrates was sustained for at least 6 weeks. No new adverse drug reactions related to the administration of sirukumab were observed in this study. These results suggest that sirukumab may reverse IL-6-mediated suppression of CYP3A, CYP2C9, and CYP2C19 activities in patients with active RA.
Subject(s)
Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/pharmacology , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/metabolism , Cytochrome P-450 Enzyme System/metabolism , Interleukin-6/immunology , Adolescent , Adult , Aged , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal, Humanized , Arthritis, Rheumatoid/blood , Caffeine/blood , Caffeine/pharmacokinetics , Drug Interactions , Female , Humans , Male , Midazolam/blood , Midazolam/pharmacokinetics , Middle Aged , Omeprazole/blood , Omeprazole/pharmacokinetics , Warfarin/blood , Warfarin/pharmacokinetics , Young AdultABSTRACT
PURPOSE: This Phase 1 pharmacokinetic (PK) comparability study in healthy subjects was performed to compare the PK properties and tolerability of single-dose golimumab 100 mg delivered subcutaneously by an autoinjector device or by a standard needle and syringe that had been used for the subcutaneous (SC) delivery of golimumab in pivotal Phase 3 studies. METHODS: Healthy male subjects were randomly assigned to receive a single injection of SC golimumab 100 mg using either the autoinjector or a standard needle and syringe. The PK parameters of golimumab were calculated using noncompartmental analysis. An ANOVA model was applied to compare the 2 injection methods with regard to golimumab C(max) and the AUC from 0 and 49 days after administration (AUC(0-49d)). FINDINGS: In the prespecified evaluable PK population (n = 141), the mean (SD) values for C(max) were 6.6 (3.3) and 6.0 (3.0) µg/mL, and AUC(0-49d) values were 97.4 (43.2) and 88.9 (36.8) µg·d/mL in the autoinjector and needle/syringe groups, respectively. The 90% CI of the geometric mean ratios of the AUC(0-49d) values between the 2 delivery methods was 95.17% to 120.55%; the 90% CI of the geometric mean ratio of C(max) was 96.14% to 127.42%. In a post hoc intent-to-treat analysis using data from all 156 subjects, the 90% CIs of both C(max) and AUC(0-49d) fell within the prespecified range for bioequivalence (80% to 125%). The prevalences of adverse events were similar between the 2 groups. IMPLICATIONS: The totality of the study findings suggests that the PK properties and tolerability of SC administration of golimumab by the 2 delivery methods were comparable. The study results successfully bridged the container-closure change from a liquid-in-vial product to either a prefilled syringe or an autoinjector with the same liquid formulation.
Subject(s)
Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal/pharmacokinetics , Adult , Analysis of Variance , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/blood , Area Under Curve , Biological Availability , Capsules , Cross-Over Studies , Equipment Failure , Healthy Volunteers , Humans , Injections, Subcutaneous/instrumentation , Male , Middle Aged , Therapeutic Equivalency , Young AdultABSTRACT
BACKGROUND: IL-23 expression is increased in psoriatic lesions and might regulate TH17 T-cell counts in patients with psoriasis. OBJECTIVES: We sought to test a novel IL-23-specific therapeutic agent for the treatment of psoriasis. METHODS: In this randomized, double-blind, placebo-controlled study the safety, tolerability, and clinical response of guselkumab, an anti-IL-23-specific mAb, were evaluated in patients with moderate-to-severe plaque psoriasis. A total of 24 patients were randomized to receive a single dose of placebo or 10, 30, 100, or 300 mg of guselkumab. Clinical response was assessed by using the Psoriasis Area and Severity Index (PASI). Additionally, histologic analysis and gene expression in skin biopsy specimens from guselkumab-treated patients were compared with those from placebo-treated patients. RESULTS: At week 12, 50% (10 mg), 60% (30 and 100 mg), and 100% (300 mg) of guselkumab-treated patients, respectively, achieved a 75% improvement in PASI scores from baseline compared with 0% of placebo-treated patients. Improvements in PASI scores were generally maintained through week 24 in all guselkumab-treated patients. The proportion of patients experiencing an adverse event was comparable between the combined guselkumab (13/20 [65.0%]) and placebo (2/4 [50.0%]) groups through week 24. Analysis of lesional and nonlesional skin biopsy specimens demonstrated decreases in epidermal thickness and T-cell and dendritic cell expression in guselkumab-treated patients compared with values seen in placebo-treated patients. At week 12, significant reductions in psoriasis gene expression and serum IL-17A levels were observed in guselkumab-treated patients. CONCLUSION: IL-23 inhibition with a single dose of guselkumab results in clinical responses in patients with moderate-to-severe psoriasis, suggesting that neutralization of IL-23 alone is a promising therapy for psoriasis.
Subject(s)
Antibodies, Monoclonal/therapeutic use , Interleukin-23/antagonists & inhibitors , Psoriasis/drug therapy , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal, Humanized , Antibodies, Neutralizing/administration & dosage , Antibodies, Neutralizing/adverse effects , Antibodies, Neutralizing/therapeutic use , Biomarkers , Biopsy , Cluster Analysis , Cytokines/blood , Cytokines/metabolism , Gene Expression Profiling , Humans , Inflammation Mediators/blood , Inflammation Mediators/metabolism , Interleukin-17/blood , Psoriasis/genetics , Psoriasis/immunology , Psoriasis/metabolism , Psoriasis/pathology , Skin/immunology , Skin/pathology , Th17 Cells/immunology , Th17 Cells/metabolism , Treatment OutcomeABSTRACT
Siltuximab, a monoclonal antibody (mAb) against interleukin (IL-6), is under development by Janssen Research & Development, LLC. During early clinical development, siltuximab was produced in a murine Sp2/0 myeloma cell line. The production cell line was switched to stably transfected Chinese hamster ovary (CHO) cell line for subsequent clinical development. A two-part, parallel-group, phase 1 study was designed to evaluate the safety and pharmacokinetics (PK) of a single IV administration of Sp2/0- and CHO-derived siltuximab in healthy subjects. The results from this study demonstrated PK comparability of siltuximab produced from Sp2/0 and CHO cell lines. The 90% confidence interval of the ratios of geometric means of Cmax and AUC0-84day following 1.4 mg/kg doses was (99.4%, 111.3%) and (98.1%, 109.6%), respectively, both within the pre-specified comparability range of 80-125%. Siltuximab derived from either the Sp2/0 or CHO cell lines was in general well tolerated and was not found to be immunogenic in this study.
Subject(s)
Antibodies, Monoclonal/pharmacokinetics , Antineoplastic Agents/pharmacokinetics , Adult , Animals , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal/biosynthesis , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/adverse effects , Area Under Curve , CHO Cells , Cell Line, Tumor , Cricetulus , Cross-Over Studies , Double-Blind Method , Female , Half-Life , Humans , Infusions, Intravenous , Male , Metabolic Clearance Rate , Mice , Middle Aged , Models, Biological , Therapeutic Equivalency , Young AdultABSTRACT
The erythropoietin mimetic antibody fusion protein CNTO 528 was developed as a novel antibody fusion protein by constructing an active hematopoietic peptide onto an IgG1-based scaffold. This resulted in a molecule with a long circulating half-life and a prolonged effect of stimulating reticulocyte production and hemoglobin (Hgb) synthesis. To assess the safety, pharmacokinetics, and pharmacodynamics of CNTO 528, the authors gave 44 adult healthy male subjects single or fractionated doses of intravenous CNTO 528 or placebo. CNTO 528 was generally well tolerated. The maximum observed concentration (Cmax) and the area under the concentration versus time curve (AUC) increased in an approximately dose-dependent manner between the 0.09-mg/kg and 0.9-mg/kg doses. The maximum effect on the reticulocyte response occurred approximately 8 to 9 days after administration. A median increase in Hgb (> or =1 g/dL above baseline) was achieved 9 to 10 days after administration, with a maximum effect between 19 and 26 days. Two subjects in the 0.9-mg/kg dose group had elevated Hgb concentrations requiring phlebotomy. In this first-in-human study, CNTO 528 was well tolerated and effective in elevating and maintaining Hgb by at least 1 g/dL following a single intravenous administration, which suggests that an erythropoietin mimetic molecule, such as CNTO 528, may be an effective therapy for patients with anemia.
Subject(s)
Antibodies, Monoclonal/administration & dosage , Hemoglobins/drug effects , Reticulocytes/drug effects , Adolescent , Adult , Anemia/drug therapy , Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/pharmacokinetics , Area Under Curve , Dose-Response Relationship, Drug , Follow-Up Studies , Hemoglobins/metabolism , Humans , Injections, Intravenous , Male , Middle Aged , Phlebotomy , Reticulocytes/metabolism , Single-Blind Method , Time Factors , Young AdultABSTRACT
Golimumab is a fully human antitumor necrosis factor alpha (TNF-alpha) monoclonal antibody that is being developed for intravenous and subcutaneous administration. To assess the pharmacokinetics and safety of the intravenous formulation of golimumab, 36 adult subjects with rheumatoid arthritis were randomly assigned to receive a single infusion of placebo or golimumab (0.1, 0.3, 1, 3, 6, or 10 mg/kg). Serum concentrations of golimumab were determined using a validated enzyme-linked immunosorbent assay method. In addition to the noncompartmental analysis and compartmental modeling, a population pharmacokinetics analysis using NONMEM was also conducted. Both the maximum serum concentration and the area under the serum concentrationtime curve appeared to increase in a dose-proportional manner. The median half-life ranged from 7 to 20 days. A 2-compartment population pharmacokinetic model adequately described the pharmacokinetics of golimumab. The following pharmacokinetic parameters (typical value [% coefficient of variation]) were estimated from the population pharmacokinetic model: clearance (CL: 0.40 [10.1%] L/d), volume of distribution in the central compartment (V(c): 3.07 [6.4%] L), intercompartmental clearance (Q: 0.42 [15.5%] L/d), and volume of distribution in the peripheral compartment (V(p): 3.68 [11.8%] L). Interindividual variability of the pharmacokinetic parameters was quantified for CL (44.3%), V(c) (25.5%), Q (44.6%), and V(p) (44.6%). Residual variability was estimated to be 15.0%. Body weight was found to be an important covariate on V(c). Golimumab was generally well tolerated. The pharmacokinetics of golimumab appeared to be linear over the dose range evaluated in this study.
Subject(s)
Antibodies, Monoclonal/pharmacokinetics , Arthritis, Rheumatoid/drug therapy , Tumor Necrosis Factor-alpha/immunology , Adult , Aged , Aged, 80 and over , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/adverse effects , Antirheumatic Agents/administration & dosage , Antirheumatic Agents/blood , Antirheumatic Agents/pharmacokinetics , Area Under Curve , Arthritis, Rheumatoid/immunology , Dose-Response Relationship, Drug , Drug Administration Schedule , Enzyme-Linked Immunosorbent Assay , Half-Life , Humans , Infusions, Intravenous , Metabolic Clearance Rate , Middle Aged , Time Factors , Treatment OutcomeABSTRACT
BACKGROUND: The ability of abciximab to prevent fibrinogen binding to activated platelets indicates it may also promote dissolution of platelet-rich thrombi. The present study examined the capacity of abciximab to reverse platelet aggregation in vitro. METHODS AND RESULTS: Experiments were performed on blood from healthy non-medicated donors. Platelet aggregate formation and disaggregation were monitored turbidimetrically. Platelet-bound fibrinogen was measured by flow cytometry. For disaggregation studies, platelets were first stimulated with either ADP or the 11-mer thrombin receptor activating peptide (TRAP), then varying amounts of abciximab were added at periodic intervals after agonist addition. Platelet disaggregation was detected by comparing the extent of light transmittance at 4 min after addition of either abciximab or saline to PRP. ATP release was simultaneously monitored by chemi-luminescence. When added 1 min after low concentrations of ADP, abciximab rapidly (< 1 min) dispersed platelet aggregates in a dose-dependent manner, with complete disaggregation observed with 6.25 microg/mL of the beta3 antagonist. In contrast, equivalent concentrations of abciximab did not induce appreciable disaggregation to platelets stimulated with TRAP (10 microM). Platelet counts of samples that had undergone complete disaggregation, as assessed by aggregometry, were equivalent to baseline, indicating dispersal of aggregates to single cells. Concentrations of abciximab that produced complete disaggregation induced partial displacement of platelet-bound fibrinogen (52 +/- 8% inhibition of fibrinogen binding at 12.5 microg/ml abciximab). The disaggregation effectiveness of abciximab decreased as the time between ADP and subsequent abciximab addition widened, and as the amount of both dense granule release and agonist stimulation increased. However, pre-treatment of platelets with acetylsalicylic acid (ASA) did not potentiate platelet disaggregation induced by abciximab. CONCLUSIONS: These data indicate that abciximab facilitates the dispersal of newly formed platelet aggregates in vitro, by partially displacing fibrinogen from activated GPIIb/IIIa receptors. In vivo, abciximab may destabilize coronary thrombi by preventing aggregate formation and dispersing mural thrombi.
Subject(s)
Antibodies, Monoclonal/pharmacology , Immunoglobulin Fab Fragments/pharmacology , Platelet Aggregation Inhibitors/pharmacology , Platelet Aggregation/drug effects , Abciximab , Adenosine Diphosphate/pharmacology , Aspirin/pharmacology , Blood Platelets/drug effects , Blood Platelets/physiology , Dose-Response Relationship, Drug , Drug Synergism , Fibrinogen/metabolism , Humans , Kinetics , Platelet Glycoprotein GPIIb-IIIa Complex/metabolism , Protein Binding/drug effectsABSTRACT
BACKGROUND: The PlA2 polymorphism of the glycoprotein IIb/IIIa (fibrinogen) receptor has been associated with increased restenosis and stent thrombosis. We postulated that this allele could alter the antiplatelet effect of abciximab in patients undergoing percutaneous coronary intervention. METHODS: Optical platelet aggregation assays, Ultegra (Accumetrics, San Diego) rapid platelet function assays, and radiometric abciximab binding assays were performed in 66 Pl(A1/A1) and 21 PlA1/A2 patients undergoing percutaneous coronary interventions. The affinity of abciximab for the PlA1 and PlA2 receptors was determined with use of transfected cells. RESULTS: Compared with PlA1/A1 homozygotes, PlA1/A2 platelets were less completely inhibited after abciximab bolus (P =.002) and at 24 hours (P =.02) as assessed by the rapid platelet function assays. Optical aggregation assays confirmed that Pl(A1/A2) platelets were less completely inhibited after abciximab bolus (P =.05). The radiometric abciximab binding assay demonstrated that the PlA1/A2 platelets had fewer baseline fibrinogen receptors than did the PlA1/A1 platelets (P =.04) and more free fibrinogen receptors at 24 hours (P =.008). Cells transfected to express homozygous PlA1 or PlA2 demonstrated a nonsignificant trend (P =.12) for reduced abciximab affinity for PlA2. CONCLUSIONS: PlA1/A2 platelets are less completely inhibited with abciximab, contributing to the observed interindividual variability in platelet function inhibition. Because the extent of platelet inhibition is an independent predictor for the risk of major adverse coronary events after percutaneous coronary intervention, the relative resistance of PlA2-positive platelets may contribute to a less favorable outcome in these patients.