A Fab of trastuzumab to treat HER2 overexpressing breast cancer brain metastases.

Despite major therapeutic advances for two decades, including the most recently approved anti-HER2 drugs, brain metastatic localizations remain the major cause of death for women with metastatic HER2 breast cancer. The main reason is the limited drug passage of the blood-brain barrier after intravenous injection and the significant efflux of drugs, including monoclocal antibodies, after administration into the cerebrospinal fluid. We hypothesized that this efflux was linked to the presence of a FcRn receptor in the blood-brain barrier. To overcome this efflux, we engineered two Fab fragments of trastuzumab, an anti-HER2 monoclonal antibody, and did a thorough preclinical development for therapeutic translational purpose. We demonstrated the safety and equal efficacy of the Fabs with trastuzumab in vitro, and in vivo using a patient-derived xenograft model of HER2 overexpressing breast cancer. For the pharmacokinetic studies of intra-cerebrospinal fluid administration, we implemented original rat models with catheter implanted into the cisterna magna. After intraventricular administration in rats, we demonstrated that the brain-to-blood efflux of Fab was up to 10 times lower than for trastuzumab, associated with a two-fold higher brain penetration compared to trastuzumab. This Fab, capable of significantly reducing brain-to-blood efflux and enhancing brain penetration after intra-cerebrospinal fluid injection, could thus be a new and original effective drug in the treatment of HER2 breast cancer brain metastases, which will be demonstrated by a phase I clinical trial dedicated to women in resort situations.

Eculizumab dose tapering should take into account the nonlinearity of its pharmacokinetics.

AIMS: Eculizumab is a monoclonal antibody targeting complement protein C5 used in renal diseases. As recommended dosing regimen leads to unnecessarily high concentrations in some patients, tailored dosing therapeutic drug monitoring was proposed to reduce treatment cost. The objectives of the present work were (i) to investigate the target-mediated elimination of eculizumab and (ii) whether a pharmacokinetic model integrating a nonlinear elimination allows a better prediction of eculizumab concentrations than a linear model. METHODS: We analysed 377 eculizumab serum concentrations from 44 patients treated for atypical haemolytic uraemic syndrome and C3 glomerulopathy with a population pharmacokinetic approach. Critical concentrations (below which a non-log-linear decline of concentration over time is evidenced) were computed to estimate the relevance of the target-mediated elimination. Simulations of dosing regimens were then performed to predict probabilities of target attainment (i.e. trough >100 mg/L). RESULTS: Pharmacokinetics of eculizumab was nonlinear and followed a mixture of first-order (CL = 1.318 mL/day/kg) and Michaelis-Menten elimination (Vmax = 26.07 mg/day, Km = 24.06 mg/L). Volume of distribution (72.39 mL/kg) and clearance were weight-dependent. Critical concentrations (Vmax/CL) ranged from 144.7 to 759.7 mg/L and were inversely related to body weight (P = .013). Nonlinearity was thus noticeable at therapeutic concentrations. Simulations predicted that 1200 mg of eculizumab every 21 days would allow 85% and 76% of patients to maintain a therapeutic exposure, for 50 or 90 kg body weight, respectively. CONCLUSIONS: Our study investigates the nonlinear elimination of eculizumab and discusses the importance of accounting for eculizumab target-mediated elimination in therapeutic drug monitoring.

Confounding mitigation for the exposure-response relationship of bevacizumab in colorectal cancer patients.

AIMS: The exposure-response relationship of bevacizumab may be confounded by various factors, including baseline characteristics, time-dependent target engagement and recursive relationships between exposure and response, requiring effective mitigation. This study aimed to investigate the exposure-response relationships of bevacizumab in metastatic colorectal cancer (mCRC) patients while mitigating potential biases. METHODS: Bevacizumab pharmacokinetics was described using target-mediated drug disposition modelling. Relationships between target kinetics, progression-free (PFS) and overall (OS) survivals were assessed using joint pharmacokinetic and parametric hazard function models. Both prognostic-driven and response-driven potential biases were mitigated. These models evaluated the impact of increased antigen target levels, clearance and intensified dosing regimen on survival. RESULTS: Estimated target-mediated pharmacokinetic parameters in 130 assessed patients were baseline target levels (R0 = 8.4 nM), steady-state dissociation constant (KSS = 10 nM) and antibody-target complexes elimination constant (kint = 0.52 day-1). The distribution of R0 was significantly associated with increased baseline concentrations of carcinoembryonic antigen, circulating vascular endothelial growth factor and the presence of extrahepatic metastases. Unbound target levels (R) significantly influenced both progression and death hazard functions. Increasing baseline target levels and/or clearance values led to decreased bevacizumab unbound concentrations, increased R levels and shortened PFS and OS, while increasing bevacizumab dose led to decreased R and longer survival. CONCLUSION: This study is the first to demonstrate the relationship between bevacizumab concentrations, target involvement and clinical efficacy by effectively mitigating potential sources of bias. Most of the target amount may be tumoural in mCRC. Future studies should provide a more in-depth description of this relationship.

Efficacy and safety of intravenous bevacizumab on severe bleeding associated with hemorrhagic hereditary telangiectasia: A national, randomized multicenter trial.

BACKGROUND: Bevacizumab-a humanized monoclonal antibody-has been widely used to treat patients with hereditary hemorrhagic telangiectasia (HHT), but no randomized trial has yet been conducted. METHODS: This study is a double-blind multicenter randomized phase 2 trial with a 1:1 active-treatment-to-placebo ratio. We included patients over the age of 18 with a confirmed diagnosis and the need for at least four red blood cell (RBC) units transfused in the 3 months before study enrollment. Bevacizumab was administered at a dose of 5 mg/kg every 14 days with a total of six injections. The primary efficacy criterion was a decrease of at least 50% in the cumulative number of RBC units transfused in a 3-month period before and after treatment. RESULTS: A total of 24 patients (12 in each group) were included and randomized at 4 different centers. In intention-to-treat analysis, 63.6% of patients (7/11) in the bevacizumab group versus 33.3% of patients (4/12) in the placebo group decreased the number of blood transfusions by at least 50% (p = 0.22). Hemoglobin levels significantly improved at 6 months in the bevacizumab versus placebo group (p = 0.02). The pharmacokinetics study revealed that patients with high exposure to bevacizumab had a significant decrease in RBC transfusions (p = 0.03). Fifty-nine adverse events were observed, 34 in the placebo arm versus 25 in the bevacizumab arm. CONCLUSION: Though the present trial was underpowered, patients with HHT receiving bevacizumab required numerically fewer red blood cell transfusions than those receiving placebo, particularly those with high exposure.

Relationship Between Cetuximab Target-Mediated Pharmacokinetics and Progression-Free Survival in Metastatic Colorectal Cancer Patients.

BACKGROUND AND OBJECTIVE: Cetuximab, an anti-epidermal growth factor receptor (EGFR) monoclonal immunoglobulin (Ig)G1 antibody, has been approved for the treatment of metastatic colorectal cancer (mCRC). The influence of target-antigen on cetuximab pharmacokinetics has never been investigated using target-mediated drug disposition (TMDD) modelling. This study aimed to investigate the relationship between cetuximab concentrations, target kinetics and progression-free survival (PFS). METHODS: In this ancillary study (NCT00559741), 91 patients with mCRC treated with cetuximab were assessed. Influence of target levels on cetuximab pharmacokinetics was described using TMDD modelling. The relationship between cetuximab concentrations, target kinetics and time-to-progression (TTP) was described using a joint pharmacokinetic-TTP model, where unbound target levels were assumed to influence hazard of progression by an Emax model. Mitigation strategies of concentration-response relationship, i.e., time-varying endogenous clearance and mutual influences of clearance and time-to-progression were investigated. RESULTS: Cetuximab concentration-time data were satisfactorily described using the TMDD model with quasi-steady-state approximation and time-varying endogenous clearance. Estimated target parameters were baseline target levels (R0 = 43 nM), and complex elimination rate constant (kint = 0.95 day-1). Estimated time-varying clearance parameters were time-invariant component of CL (CL0= 0.38 L/day-1), time-variant component of CL (CL1= 0.058 L/day-1) and first-order rate of CL1 decreasing over time (kdes = 0.049 day-1). Part of concentration-TTP was TTP-driven, where clearance and TTP were inversely correlated. In addition, increased target occupancy was associated with increased TTP. CONCLUSION: This is the first study describing the complex relationship between cetuximab target-mediated pharmacokinetics and PFS in mCRC patients using a joint PK-time-to-progression model. Further studies are needed to provide a more in-depth description of this relationship.

Treatment of chronic hepatitis B: virological and pharmacological aspects / Traitement de l'hépatite B chronique par ténofovir : aspects virologiques et pharmacologiques

Tenofovir is a nucleotidic analog inhibitor used in monotherapy as first line treatment of chronic Hepatitis B virus (HBV) infection. This drug requires a two-step phosphorylation by cellular kinases. The active triphosphate form inhibits viral DNA polymerase. Tenofovir has a very low oral bioavailability following oral administration. Hence, its oral administration requires the use of prodrugs: tenofovir disoproxil fumararate (TDF) or tenofovir alafénamide (TAF). TAF demonstrated a lower kidney and bone toxicity than TDF. TAF and TDF treatments allow prevention of chronic hepatitis B complications, which are cirrhosis and hepatocellular carcinoma. Prevention of these complications requires a virological response to the treatment, defined as undetectable HBV DNA. TDF and TAF are associated with virological response rates from 64 to 94 % after one year of treatment. This rate depends on HBV viral load at diagnostic, HBe antigen status, mutations in the HBV polymerase gene (Pol/RT) and patient compliance to the treatment. Tenofovir has a high genetic barrier and resistance mutations to this drug have not yet been described. However, mutations rt181T/V and/or rtN236T have been associated with reduced susceptibility to TDF/TAF in vitro and delayed response in vivo. Recently described mutations CYEI and rtA194T have been associated with reduced susceptibility to TDF/TAF in vitro without any change in viral response in vivo. Patient compliance can be improved using cognitive behavioral therapy, supporter interventions and use of short message service. Finally, some genetic polymorphisms in MRP(multidrug resistance-associated protein)-2 and MRP4 efflux transporters could be associated with TDF toxicity and virological response to TDF or TAF. In the perspective of functional HBV cure, TDF and TAF are likely to be still used, in association with new class of antivirals. For this reason, it is important to further characterize the pharmacological and virological factors associated with partial virological response to tenofovir.

Le ténofovir est un analogue nucléotidique inhibiteur de l'ADN polymérase à activité de transcriptase inverse du virus de l'hépatite B (VHB). Il nécessite une métabolisation intra-cellulaire par des kinases cellulaires pour obtenir la forme triphosphate active. Cette dernière est incorporée à l'ADN viral en cours de synthèse et exerce un effet terminateur de chaîne. Le ténofovir est administré sous forme de promédicaments : le ténofovir disoproxil fumarate (TDF) ou le ténofovir alafénamide (TAF). Le TAF se caractérise par une meilleure tolérance rénale et osseuse que le TDF. Le TDF et le TAF sont indiqués en monothérapie de longue durée pour le traitement de première intention des hépatites B chroniques. Ce traitement permet de prévenir la cirrhose et le carcinome hépatocellulaire qui sont les principales complications de l'hépatite B chronique. Le critère principal de suivi est l'obtention d'une réponse virologique, définie par une charge virale VHB indétectable. Le TDF et le TAF sont associés à des taux de réponse virologique de 64 à 94 % après un an de traitement. Ce taux de réponse dépend de facteurs virologiques, notamment le statut antigène HBe, la charge virale VHB au diagnostic et la présence de certaines mutations dans la polymérase virale (Pol/RT). Aucune résistance au ténofovir n'a été décrite au cours des essais cliniques, ce qui reflète la barrière génétique élevée associée à cette molécule. Néanmoins, les mutations rt181T/V et/ou rtN236T peuvent réduire la sensibilité au ténofovir in vitro et retarder la réponse virologique in vivo. Les mutations CYEI et A194T, récemment décrites, diminuent aussi la sensibilité au ténofovir in vitro mais ne semblent pas avoir d'impact sur la réponse au traitement. La réponse virologique dépend aussi de facteurs de l'hôte, principalement l'observance au traitement, cruciale pour prévenir les complications de l'infection. Cette observance peut être améliorée par des approches comportementales, le soutien d'un tiers ou des rappels par message texte. Enfin, certains polymorphismes génétiques au niveau des transporteurs MRP (multidrug resistance-associated protein)-2 ou MRP4 pourraient moduler la réponse virologique et la tolérance rénale du ténofovir. Dans une perspective de guérison fonctionnelle de l'hépatite chronique B, le ténofovir sera très probablement toujours utilisé, en association avec de nouveaux antiviraux. Pour ces raisons, il semble important de poursuivre l'identification des facteurs pharmacologiques et virologiques associés à la réponse virologique au ténofovir.

Is CD25 blockade optimal in kidney transplant patients treated with basiliximab? A target-mediated drug disposition model.

AIMS: Basiliximab, an anti-CD25 chimeric monoclonal antibody, is approved in prevention of acute kidney transplant rejection. This study aims at investigating target-mediated pharmacokinetics of basiliximab. METHODS: Data from the IDEALE study, where 16 kidney transplant patients were treated with 2 40- or 80-mg basiliximab injections, were reanalysed. Basiliximab pharmacokinetics was described using a population 2-compartment target-mediated drug disposition model with the quasi-steady-state approximation. RESULTS: Volume of distribution was significantly higher in males (P = .029). Estimated baseline target antigen (CD25) level was lower is patients cotreated with cyclosporine (P = .026). CONCLUSION: This analysis allows the first description of the target-mediated nonlinear elimination of basiliximab. Our results suggest that cyclosporine cotreatment is associated with decreased target level and that an optimized dosing regimen may improve basiliximab effects.

Relationship Between Antithymocyte Globulin Concentrations and Lymphocyte Sub-Populations in Kidney Transplant Patients.

BACKGROUND: Rabbit antithymocyte globulins (rATGs) are polyclonal antibodies used to prevent acute cellular rejection in kidney transplantation. Their dosing remains largely empirical and the question of an individualized dose is still unresolved. METHODS: Data from a prospective study in 17 kidney transplant patients were used to develop a model describing the dose-concentration-response relationship of rATG with T-lymphocyte subpopulation counts over time. The model was validated using an independent cohort of kidney transplant patients treated by rATG in the same center. RESULTS: Pharmacokinetics of rATG was described using a two-compartment model integrating a third compartment and a target-mediated elimination for active rATG. The kinetics of CD3+, CD4+, CD8+, and CD3-CD56+ cell counts over time were described by a pharmacokinetic-pharmacodynamic model with transit compartments, integrating both CD3-CD56+-independent and CD3-CD56+-dependent rATG-mediated lymphocyte depletion, and a positive feedback. Elimination of rATG was influenced by age and body surface area, while its distribution was also influenced by body surface area. CD3+ proliferation rate decreased with age and CD3-CD56+-mediated elimination was influenced by the V158F-FCGR3A polymorphism. Binary efficacy and tolerance endpoints were defined as a CD3+ count < 20 mm-3 for at least 7 days and a CD4+ count > 200 mm-3 at 1 year, respectively. Simulations showed that increasing or decreasing the standard 6-mg/kg dose will impact both tolerance and efficacy, while a dose decrease may be beneficial in elderly patients. CONCLUSIONS: Our results can be used to design prospective clinical trials testing dose individualization based on patients' characteristics. CLINICAL TRIAL REGISTRATION: Eudract No. 2009-012673-35.

Infliximab Treatment Does Not Lead to Full TNF-α Inhibition: A Target-Mediated Drug Disposition Model.

BACKGROUND AND OBJECTIVE: Infliximab, an anti-tumour necrosis factor (TNF)-α monoclonal antibody, has been approved in chronic inflammatory disease, including rheumatoid arthritis, Crohn's disease and ankylosing spondylitis. This study aimed to investigate and characterise target-mediated drug disposition of infliximab and antigen mass turnover during infliximab treatment. METHODS: In this retrospective cohort of 186 patients treated with infliximab for rheumatoid arthritis, Crohn's disease or ankylosing spondylitis, trough infliximab concentrations were determined from samples collected between weeks 0 and 22 after treatment initiation. Target-mediated pharmacokinetics of infliximab was described using target-mediated drug disposition modelling. Target-mediated elimination parameters were determined for rheumatoid arthritis and Crohn's disease, assuming ankylosing spondylitis with no target-mediated elimination. RESULTS: The quasi-equilibrium approximation of a target-mediated drug disposition model allowed a satisfactory description of infliximab concentration-time data. Estimated baseline TNF-α amounts were similar in Crohn's disease and rheumatoid arthritis (R0 = 0.39 vs 0.46 nM, respectively), but infliximab-TNF complex elimination was slower in Crohn's disease than in rheumatoid arthritis (kint = 0.024 vs 0.061 day-1, respectively). Terminal elimination half-lives were 13.5, 21.5 and 16.5 days for rheumatoid arthritis, Crohn's disease and ankylosing spondylitis, respectively. Estimated amounts of free target were close to baseline values before the next infusion suggesting that TNF-α inhibition may not be sustained over the entire dose interval. CONCLUSIONS: The present study is the first to quantify the influence of target antigen dynamics on infliximab pharmacokinetics. Target-mediated elimination of infliximab may be complex, involving a multi-scale turnover of TNF-α, especially in patients with Crohn's disease. Additional clinical studies are warranted to further evaluate and fine-tune dosing approaches to ensure sustained TNF-α inhibition.

The Influence of Underlying Disease on Rituximab Pharmacokinetics May be Explained by Target-Mediated Drug Disposition.

BACKGROUND AND OBJECTIVES: Rituximab is an anti-CD20 monoclonal antibody approved in several diseases, including chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), rheumatoid arthritis (RA), and anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). The influence of underlying disease on rituximab pharmacokinetics has never been investigated for several cancer and non-cancer diseases simultaneously. This study aimed at assessing this influence using an integrated semi-mechanistic model accounting for target-mediated elimination of rituximab. METHODS: Rituximab concentration-time data from five studies previously published in patients with CLL, DLBCL, FL, RA, and AAV were described using a two-compartment model with irreversible binding of rituximab to its target antigen. Both underlying disease and target antigen measurements were assessed as covariates. RESULTS: Central volume of distribution was [95% confidence interval] 1.7-fold [1.6-1.9] higher in DLBCL than in RA, FL, and CLL, and it was 1.8-fold [1.6-2.1] higher in RA, FL, and CLL than in AAV. First-order elimination rate constants were 1.8-fold [1.7-2.0] and 1.3-fold [1.2-1.5] higher in RA, DLBCL, and FL than in CLL and AAV, respectively. Baseline latent antigen level (L0) was 54-fold [30-94], 20-fold [11-36], and 29-fold [14-64] higher in CLL, DLBCL, and FL, respectively, than in RA and AAV. In lymphoma, L0 increased with baseline total metabolic tumor volume (p = 6.10-7). In CLL, the second-order target-mediated elimination rate constant (kdeg) increased with baseline CD20 count on circulating B cells (CD20cir, p = 0.0081). CONCLUSIONS: Our results show for the first time that rituximab pharmacokinetics is strongly influenced by underlying disease and disease activity. Notably, neoplasms are associated with higher antigen amounts that result in decreased exposure to rituximab compared to inflammatory diseases. Our model might be used to estimate unbound target amounts in upcoming studies.

Infliximab Efficacy May Be Linked to Full TNF-α Blockade in Peripheral Compartment-A Double Central-Peripheral Target-Mediated Drug Disposition (TMDD) Model.

Infliximab is an anti-TNF-α monoclonal antibody approved in chronic inflammatory bowel diseases (IBD). This study aimed at providing an in-depth description of infliximab target-mediated pharmacokinetics in 133 IBD patients treated with 5 mg/kg infliximab at weeks 0, 2, 14, and 22. A two-compartment model with double target-mediated drug disposition (TMDD) in both central and peripheral compartments was developed, using a rich database of 26 ankylosing spondylitis patients as a reference for linear elimination kinetics. Population approach and quasi-steady-state (QSS) approximation were used. Concentration-time data were satisfactorily described using the double-TMDD model. Target-mediated parameters of central and peripheral compartments were respectively baseline TNF concentrations (RC0 = 3.3 nM and RP0 = 0.46 nM), steady-stated dissociation rates (KCSS = 15.4 nM and KPSS = 0.49 nM), and first-order elimination rates of complexes (kCint = 0.17 day-1 and kPint = 0.0079 day-1). This model showed slower turnover of targets and infliximab-TNF complex elimination rate in peripheral compartment than in central compartment. This study allowed a better understanding of the multi-scale target-mediated pharmacokinetics of infliximab. This model could be useful to improve model-based therapeutic drug monitoring of infliximab in IBD patients.

A phase II randomised study of preoperative trastuzumab alone or combined with everolimus in patients with early HER2-positive breast cancer and predictive biomarkers (RADHER trial).

INTRODUCTION: Resistance to trastuzumab in breast cancer is an ongoing challenge. Clinical and biological effects of co-targeting HER2 and mammalian target of rapamycin (mTOR) in patients with HER2-positive early operable breast cancer via the addition of everolimus to preoperative trastuzumab were evaluated in a phase II randomised study. METHODS: Patients were randomised 1:1 to receive trastuzumab (4 mg/kg initial dose then 2 mg/kg weekly for 5 weeks) alone or combined with everolimus (10 mg/day for 6 weeks) and then underwent surgery. Tumours were assessed by clinical examination and echography at the baseline and on treatment. The primary end-point was the clinical response rate at 6 weeks. Pathological response and safety were also evaluated. Baseline and surgery tumour samples were assessed by immunohistochemistry and multiplex immunoanalysis for predictive downstream effectors of the PI3K/AKT/mTOR and MAP kinase (MAPK) pathways. RESULTS: Eighty-two patients were enrolled, 41 per arm. The clinical response rates were 34.1% and 43.9% with trastuzumab alone and combined with everolimus, respectively. Pathological response rates were 43.6% and 47.5%, respectively. Addition of everolimus increased toxicity, notably mucositis (82.5% versus 5.0%) and rash (57.5% versus 10.0%), but grade III/IV events were rare. No correlation between response to treatments and baseline candidate biomarkers was identified, except for PIK3CA mutations which were found to predict trastuzumab resistance. Significant changes were seen in several MAPK pathway effectors after combination therapy. CONCLUSIONS: The addition of everolimus did not improve the efficacy, but induced MAPK signalling. Combination therapy to overcome pathway cross-talk should be considered to maximise the effectiveness of trastuzumab in this setting. ClinicalTrial.gov Identifier NCT00674414.

Association of IgG1 Antibody Clearance with FcγRIIA Polymorphism and Platelet Count in Infliximab-Treated Patients.

The FcγRIIA/CD32A is mainly expressed on platelets, myeloid and several endothelial cells. Its affinity is considered insufficient for allowing significant binding of monomeric IgG, while its H131R polymorphism (histidine > arginine at position 131) influences affinity for multimeric IgG2. Platelet FcγRIIA has been reported to contribute to IgG-containing immune-complexe clearance. Given our finding that platelet FcγRIIA actually binds monomeric IgG, we investigated the role of platelets and FcγRIIA in IgG antibody elimination. We used pharmacokinetics analysis of infliximab (IgG1) in individuals with controlled Crohn's disease. The influence of platelet count and FcγRIIA polymorphism was quantified by multivariate linear modelling. The infliximab half-life increased with R allele number (13.2, 14.4 and 15.6 days for HH, HR and RR patients, respectively). It decreased with increasing platelet count in R carriers: from ≈20 days (RR) and ≈17 days (HR) at 150 × 109/L, respectively, to ≈13 days (both HR and RR) at 350 × 109/L. Moreover, a flow cytometry assay showed that infliximab and monomeric IgG1 bound efficiently to platelet FcγRIIA H and R allotypes, whereas panitumumab and IgG2 bound poorly to the latter. We propose that infliximab (and presumably any IgG1 antibody) elimination is partly due to an unappreciated mechanism dependent on binding to platelet FcγRIIA, which is probably tuned by its affinity for IgG2.

Panitumumab and cetuximab affect differently miRNA expression in colorectal cancer cells.

Background & aim: Resistance to anti-EGFR monoclonal antibodies in metastatic colorectal cancer (CRC) is frequent and prognostic biomarkers are lacking. MicroRNAs (miR) are good candidates in this context. We aimed to characterize cetuximab and panitumumab exposure influence on miR expression in colorectal cancer cells to identify those regulating the EGFR pathway and implicated in resistance to treatment. Finally, we aimed to identify miR expression in serum of patients with advanced CRC treated with cetuximab or panitumumab. Results: Cetuximab and panitumumab exposure induced significant expression variations of 17 miR out of a miRnome panel of 752. Six of those miR interacted with at least one downstream element of the EGFR pathway. Conclusion: After the bioinformatics two-phase process, five miR rarely described before could be potential actors of anti-EGFR monoclonal antibody resistance: miR-95-3p, miR-139-5p, miR-145-5p, miR-429 and miR-1247-5p. In vivo, we detected the expression of miR-139-5p and miR-145-5p in serum of patients with metastatic CRC.

Cardiovascular Adverse Events With Intravitreal Anti-Vascular Endothelial Growth Factor Drugs: A Systematic Review and Meta-analysis of Randomized Clinical Trials.

IMPORTANCE: Systemic safety of intravitreal anti-vascular endothelial growth factor (anti-VEGF) is a matter of debate and regular updates are necessary. OBJECTIVE: To evaluate systemic adverse events (SAEs) associated with intravitreal anti-VEGF drugs compared with non-anti-VEGF treatments in patients with ocular diseases. DATA SOURCES: Electronic searches were conducted in MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases from inception to July 7, 2020. STUDY SELECTION: Randomized clinical trials conducted in adults with retinal diseases who received intravitreal anti-VEGF drugs. DATA EXTRACTION AND SYNTHESIS: Studies and treatment characteristics and outcome data were extracted and analyzed, and study quality was evaluated. MAIN OUTCOMES AND MEASURES: Main outcomes were major cardiovascular events (MACEs) and total mortality. Secondary outcomes included nonocular hemorrhage, components of MACEs, other cardiovascular outcomes, serious SAEs, and all SAEs. RESULTS: A total of 74 randomized clinical trials were analyzed: 32 trials (43%) included 14 190 patients with age-related macular degeneration (AMD), 24 (32%) included 5424 patients with diabetic retinopathy (diabetic macular edema or proliferative diabetic retinopathy), 17 trials (23%) included 3757 patients with retinal vein occlusion, and 1 trial (1%) included 122 patients with myopic choroidal neovascularization. Anti-VEGF drug administration did not increase MACEs compared with control agents (odds ratio [OR], 1.16; 95% CI, 0.85-1.58) or total mortality (OR, 1.27; 95% CI, 0.82-1.96). There was an interaction (subgroup difference, P = .04) in mortality risk depending on the underlying disease with an increase (OR, 1.80; 95% CI, 1.03-3.16; P = .04) in the risk of death in patients with diabetic retinopathy; however, no increase was observed in patients with AMD or retinal vein occlusion. Administration of anti-VEGF drugs increased the risk of nonocular hemorrhage (OR, 1.46; 95% CI, 1.01-2.10), mainly in patients with AMD. CONCLUSIONS AND RELEVANCE: Intravitreal anti-VEGF was not associated with an increase in MACEs in the trials examined herein. Increased mortality in patients with diabetes and nonocular hemorrhages, especially in those with AMD, could represent a safety signal, but the evidence was not strong. However, continued surveillance of SAEs remains warranted.

A robust enzyme-linked immunosorbent assay to measure serum ramucirumab concentrations.

Aim: Ramucirumab, an anti-VEGFR2 monoclonal antibody, has been approved for the treatment of metastatic gastric and colorectal cancer. An assay measuring ramucirumab serum concentrations was needed to investigate its pharmacokinetics and concentration-response relationship. Results: An ELISA was developed and validated according to the international guidelines for ligand-binding assays. Ramucirumab calibration standards ranged from 0.125 to 40 mg/l. Low, middle and high quality controls were spiked at 0.2, 4 and 8 mg/l, respectively. The limits of quantification were established to be 0.125 and 10 mg/l for LLOQ and ULOQ, respectively. No cross-reactivity with anti-VEGF or anti-EGFR was detected. Conclusion: This in-house-developed ELISA is sensitive, accurate, reproducible and suitable for pharmacokinetic studies of ramucirumab.

Antigen Mass May Influence Trastuzumab Concentrations in Cerebrospinal Fluid After Intrathecal Administration.

Intravenous administration of monoclonal antibodies leads to low concentrations in the central nervous system, which is a serious concern in neuro-oncology, especially in leptomeningeal carcinomatosis of HER2-overexpressing breast cancer. Case reports of i.t. administrations of trastuzumab have shown promising results in these patients but dosing regimens are empirical in absence of pharmacokinetic (PK) study. With a population PK approach, we described the fate of trastuzumab after i.t. administration in 21 women included in a phase I-II clinical trial. Trastuzumab was administered by i.t. route every week for 8 weeks and both cerebrospinal fluid (CSF) and serum were sampled to measure trough concentrations. Some patients showed noticeable CSF concentration fluctuations predicted using a target-mediated drug disposition. This target was latent and produced with a delayed feedback. Apparent volumes of distribution were close to physiological volumes (V1  = 3.25 L, V2  = 0.644 L, for serum and CSF, respectively). Estimated (constant) transfer from serum to CSF was very slow (k12  = 0.264 mg/day) whereas estimated half-life of transfer from CSF to serum was rapid (2.2 days). From the individual parameters of patients, a single i.t. administration of 150 mg of trastuzumab corresponded to median mean residence times of 3.8 days and 15.6 days in CSF and serum, respectively. Survival without neurological relapse was not related to trastuzumab exposure. This study confirms that transfer of trastuzumab from serum to CSF is very limited and that this monoclonal antibody, when administered by i.t. route, is rapidly transferred to the serum.