Sialic Acid Mediated Endothelial and Hepatic Uptake: A Mechanism based Mathematic Model Elucidating the Complex Pharmacokinetics and Pharmacodynamics of Efmarodocokin Alfa, a Variably Glycosylated Fusion Protein.

Sialic acid (SA) is crucial for protecting glycoproteins from clearance. Efmarodocokin alfa (IL-22Fc), a fusion protein agonist that links IL-22 to the crystallizable fragment (Fc) of human IgG4, contains 8 N-glycosylation sites and exhibits heterogeneous and variable terminal sialylation biodistribution. This presents a unique challenge for Pharmacokinetic (PK) and Pharmacodynamic (PD) analysis and cross-species translation. In this study, we sought to understand how varying SA levels and heterogeneous distribution contribute to IL-22Fc's complex PKPD properties. We initially used homogenous drug material with varying SA levels to examine PKPD in mice. Population PKPD analysis based on mouse data revealed that SA was a critical covariate simultaneously accounting for the substantial between subject variability (BSV) in clearance (CL), distribution clearance (CLd), and volume of distribution (Vd). In addition to the well-established mechanism by which SA inhibits ASGPR activity, we hypothesized a novel mechanism by which decrease in SA increases the drug uptake by endothelial cells. This decrease in SA, leading to more endothelial uptake, was supported by the neonatal Fc receptor (FcRn) dependent cell-based transcytosis assay. The population analysis also suggested in vivo EC50 (IL-22Fc stimulating Reg3ß) was independent on SA, while the in-vitro assay indicated a contradictory finding of SA-in vitro potency relationship. We created a mechanism based mathematical (MBM) PKPD model incorporating the decrease in SA mediated endothelial and hepatic uptake, and successfully characterized the SA influence on IL-22Fc PK, as well as the increased PK exposure being responsible for increased PD. Thereby, the MBM model supported that SA has no direct impact on EC50, aligning with the population PKPD analysis. Subsequently, using the MBM PKPD model, we employed 5 subpopulation simulations to reconstitute the heterogeneity of drug material. The simulation accurately predicted the PKPD of heterogeneously and variably sialylated drug in mouse, monkey and human. The successful prospective validation confirmed the MBM's ability to predict IL-22Fc PK across variable SA levels, homogenous to heterogeneous material, and across species (R2=0.964 for clearance prediction). Our model prediction suggests an average of 1 mol/mol SA increase leads to a 50% increase in drug exposure. This underlines the significance of controlling sialic acid levels during lot-to-lot manufacturing.

Engineering interferons and interleukins for cancer immunotherapy.

Cytokines are a class of potent immunoregulatory proteins that are secreted in response to various stimuli and act locally to regulate many aspects of human physiology and disease. Cytokines play important roles in cancer initiation, progression, and elimination, and thus, there is a long clinical history associated with the use of recombinant cytokines to treat cancer. However, the use of cytokines as therapeutics has been limited by cytokine pleiotropy, complex biology, poor drug-like properties, and severe dose-limiting toxicities. Nevertheless, cytokines are crucial mediators of innate and adaptive antitumor immunity and have the potential to enhance immunotherapeutic approaches to treat cancer. Development of immune checkpoint inhibitors and combination immunotherapies has reinvigorated interest in cytokines as therapeutics, and a variety of engineering approaches are emerging to improve the safety and effectiveness of cytokine immunotherapy. In this review we highlight recent advances in cytokine biology and engineering for cancer immunotherapy.

An engineered IL-21 with half-life extension enhances anti-tumor immunity as a monotherapy or in combination with PD-1 or TIGIT blockade.

Interleukin-21 (IL-21) has exhibited anti-tumor activity in preclinical and clinical studies; however, its modest efficacy and short half-time has limited its therapeutic utility as a monotherapy. Therefore, we engineered a fusion protein (IL-21-αHSA) in which a nanobody targeting human serum albumin (HSA) was fused to the C-terminus of rhIL-21. The αHSA nanobody displayed broad species cross-reactivity and bound to a HSA epitope that does not overlap with the FcRn binding site, thus providing a strategic design for half-life extension. The IL-21-αHSA fusion protein showed increased stability compared to rhIL-21, while retaining its bioactivity in a liquid solution for at least 6 months. Moreover, IL-21-αHSA showed a dramatically extended half-life and prolonged exposure in cynomolgus monkeys, with the t1/2 and AUC nearly 10 and 50 times greater than that of rhIL-21, respectively. Furthermore, IL-21-αHSA displayed enhanced anti-tumor efficacy in two syngeneic mouse models. Notably, IL-21-αHSA increased the anti-tumor effect of programmed cell death protein 1 (PD-1) and T cell immunoglobulin and ITIM domain (TIGIT) blockades when used in combination, with a protection against tumor rechallenge, suggesting the formation of long-term anti-tumor memory response. KEGG analysis identified significantly enriched pathways associated with anti-tumor immune response, with increased expression of genes associated with CD8+ T and NK cell cytotoxicity. Overall, these data support further clinical evaluation of IL-21-αHSA as a monotherapy or in combination with immune checkpoint blockades.

IFN-λ therapy prevents severe gastrointestinal graft-versus-host disease.

Immunopathology and intestinal stem cell (ISC) loss in the gastrointestinal (GI) tract is the prima facie manifestation of graft-versus-host disease (GVHD) and is responsible for significant mortality after allogeneic bone marrow transplantation (BMT). Approaches to prevent GVHD to date focus on immune suppression. Here, we identify interferon-λ (IFN-λ; interleukin-28 [IL-28]/IL-29) as a key protector of GI GVHD immunopathology, notably within the ISC compartment. Ifnlr1-/- mice displayed exaggerated GI GVHD and mortality independent of Paneth cells and alterations to the microbiome. Ifnlr1-/- intestinal organoid growth was significantly impaired, and targeted Ifnlr1 deficiency exhibited effects intrinsic to recipient Lgr5+ ISCs and natural killer cells. PEGylated recombinant IL-29 (PEG-rIL-29) treatment of naive mice enhanced Lgr5+ ISC numbers and organoid growth independent of both IL-22 and type I IFN and modulated proliferative and apoptosis gene sets in Lgr5+ ISCs. PEG-rIL-29 treatment improved survival, reduced GVHD severity, and enhanced epithelial proliferation and ISC-derived organoid growth after BMT. The preservation of ISC numbers in response to PEG-rIL-29 after BMT occurred both in the presence and absence of IFN-λ-signaling in recipient natural killer cells. IFN-λ is therefore an attractive and rapidly testable approach to prevent ISC loss and immunopathology during GVHD.

Safety and Immunological Evaluation of Interleukin-21 Plus Anti-α4ß7 mAb Combination Therapy in Rhesus Macaques.

Human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) infections compromise gut immunological barriers, inducing high levels of inflammation and a severe depletion of intestinal CD4+ T cells. Expression of α4ß7 integrin promotes homing of activated T cells to intestinal sites where they become preferentially infected; blockade of α4ß7 with an anti-α4ß7 monoclonal antibody (mAb) prior to infection has been reported to reduce gut SIV viremia in rhesus macaques (RMs). Interleukin-21 (IL-21) administration in antiretroviral therapy-treated, SIV-infected RMs reduces gut inflammation and improves gut integrity. We therefore hypothesized that the combination of IL-21 and anti-α4ß7 mAb therapies could synergize to reduce inflammation and HIV persistence. We co-administered two intravenous doses of rhesus anti-α4ß7 mAb (50 mg/kg) combined with seven weekly subcutaneous infusions of IL-21-IgFc (100 µg/kg) in four healthy, SIV-uninfected RMs to evaluate the safety and immunological profiles of this intervention in blood and gut. Co-administration of IL-21 and anti-α4ß7 mAb showed no toxicity at the given dosages as assessed by multiple hematological and chemical parameters and did not alter the bioavailability of the therapeutics or result in the generation of antibodies against the anti-α4ß7 mAb or IL-21-IgFc. Upon treatment, the frequency of CD4 memory T cells expressing ß7 increased in blood and decreased in gut, consistent with an inhibition of activated CD4 T-cell homing to the gut. Furthermore, the frequency of T cells expressing proliferation and immune activation markers decreased in blood and, more profoundly, in gut. The combined IL-21 plus anti-α4ß7 mAb therapy is well-tolerated in SIV-uninfected RMs and reduces the gut homing of α4ß7+ CD4 T cells as well as the levels of gut immune activation.

IL-20 promotes epithelial healing of the injured mouse cornea.

After corneal epithelial injury, the ensuing inflammatory response is necessary for efficient wound healing. While beneficial healing effects are attributed to recruited neutrophils and platelets, dysregulated inflammation (too little or too much) is associated with impaired wound healing. The purpose of this study was to use an established C57BL/6J mouse model of corneal injury to evaluate the potential modulatory role of interleukin-20 (IL-20) on the inflammatory and healing responses to epithelial wounding. In the uninjured cornea, immunofluorescence staining for IL-20 and its receptor, IL-20RA, was observed on basal epithelial cells at the limbus. After a 2 mm central epithelial abrasion, IL-20 staining was also observed in stromal keratocytes and ELISA studies showed a significant increase (nearly 3-fold) in IL-20 expression. Injured corneas healed more slowly when treated with a topical application of a neutralizing anti-IL-20 antibody. While corneal epithelial cell division and epithelial nerve recovery measured at 24 h post-injury were reduced compared to controls, neutrophil influx into the cornea was increased. In contrast, topical application of recombinant IL-20 (rIL-20) decreased corneal inflammation as evidenced by reductions in limbal vessel dilatation, platelet extravasation, neutrophil recruitment and CXCL1 expression. In wild type mice, topical rIL-20 had a limited effect on corneal wound healing and resulted in only a slight increase in epithelial cell division and epithelial nerve recovery; the rate of wound closure was unaffected. To clarify the effect of IL-20 on corneal wound healing, rIL-20 was topically applied to neutropenic wild type (WT) mice and mutant mice (ɣδ T cell deficient mice and CD11a deficient mice), all of which have well characterized reductions in neutrophil recruitment and delayed wound healing after corneal injury. In each case, rIL-20 restored corneal wound healing to baseline levels while neutrophil recruitment remained low. Thus, it appears that IL-20 plays a beneficial and direct role in corneal wound healing while negatively regulating neutrophil and platelet infiltration.

Inhibition of JAK3 and PKC via Immunosuppressive Drugs Tofacitinib and Sotrastaurin Inhibits Proliferation of Human B Lymphocytes In Vitro.

BACKGROUND: Antibody-mediated response in solid organ transplantation is critical for graft dysfunction and loss. The use of immunosuppressive agents partially inhibits the B-lymphocyte response leading to a risk of acute and chronic antibody-mediated rejection. This study evaluated the impact of JAK3 and PKC inhibitors tofacitinib (Tofa) and sotrastaurin (STN), respectively, on B-cell proliferation, apoptosis, and activation in vitro. METHODS: Human B cells isolated from peripheral blood of healthy volunteers were cocultured with CD40 ligand-transfected fibroblasts as feeder cells in the presence of interleukin (IL) 2, IL-10, and IL-21. The cocultures were treated with immunosuppressants Tofa, STN, and rapamycin (as a control), to analyze the proliferation and apoptosis of B cells by means of Cyquant and flow cytometry, respectively. CD27 and IgG staining were applied to evaluate whether treatments modified the activation of B cells. RESULTS: Tofa and STN were able to inhibit B-cell proliferation to the same extent as rapamycin, without inducing cell apoptosis. After 6 days in coculture with feeder cells, all B cells showed CD27 memory B-cell phenotype. None of the immunosuppressive treatments modified the proportion between class-switched and non-class-switched memory B cells observed in nontreated cultures. The high predominance of CD27+CD24+ phenotype was not modified by any immunosuppressive treatment. CONCLUSIONS: Our results show that Tofa and STN can suppress B-cell antibody responses to an extent similar to rapamycin, in vitro; therefore these compounds may be a useful therapy against antibody-mediated rejection in transplantation.

The pharmacokinetics of peginterferon lambda-1a following single dose administration to subjects with impaired renal function.

AIMS: This open label study was conducted to assess the effect of renal impairment (RI) on the pharmacokinetics (PK) of peginterferon lambda-1a (Lambda). METHODS: Subjects (age 18-75 years, BMI 18-35 kg m(-2) ) were enrolled into one of five renal function groups: normal (n = 12), mild RI (n = 8), moderate RI (n = 8), severe RI (n = 7), end-stage renal disease (ESRD, n = 8) based on estimated glomerular filtration rate (eGFR) calculated using the Modification of Diet in Renal Disease (MDRD) equation. Subjects received a single dose of Lambda (180 µg) subcutaneously on day 1 followed by PK serum sample collections through day 29. Safety, tolerability and immunogenicity data were collected through day 43. PK parameters were estimated and summarized by group. Geometric mean ratios (GMR) and 90% confidence intervals (CIs) were calculated between normal and RI groups. RESULTS: With decreasing eGFR, Lambda exposure (Cmax , AUC) increased while apparent clearance (CL/F) and apparent volume of distribution (V/F) decreased. Relative to subjects with normal renal function (geometric mean AUC = 99.5 ng ml(-1) h), Lambda exposure estimates (AUC) were slightly increased in the mild RI group (geometric mean [90% CI]: 1.20 [0.82, 1.77]) and greater in the moderate (1.95 [1.35, 2.83]), severe RI (1.95 [1.30, 2.93]) and ESRD (1.88 [1.30, 2.73]) groups. Lambda was generally well tolerated. CONCLUSIONS: The results demonstrated that RI reduces the clearance of Lambda and suggests that dose modifications may not be required in patients with mild RI but may be required in patients with moderate to severe RI or ESRD.

Derivation of Phase 3 dosing for peginterferon lambda-1a in chronic hepatitis C, Part 2: Exposure-response analyses for efficacy and safety variables.

This is the second of two manuscripts detailing the pharmacodynamic derivation of peginterferon lambda-1a (Lambda) dosing and treatment durations for Phase 3 studies in hepatitis C virus (HCV) infection, based on Phase 2 data. Herein, we describe the derivation of regression models for 12-week on-treatment virologic response and safety outcomes at 120, 180, and 240 µg Lambda with ribavirin. In patients with HCV genotypes 1 or 4, there was a significant (P = 0.024) relationship between undetectable HCV-RNA at Week 4 and Lambda exposure (AUC or Cmax ), with the largest difference between adjacent dose levels between the 180 and 120 µg exposure ranges. Risk of Grade 3-4 aminotransferase or bilirubin elevations relative to a peginterferon alfa-2a/ribavirin control were related to Lambda exposure for all patients, and the largest increase between adjacent dose levels was seen for 240 versus 180 µg. Anemia and neutropenia events were lower than control across all doses and exposures. Based on these data and those in our previous manuscript, Phase 3 studies will evaluate fixed 180 µg doses of Lambda in combination with ribavirin and a direct-acting antiviral for 24-48 weeks in HCV genotypes 1 or 4 or 12-24 weeks in genotypes 2 or 3.

Derivation of Phase 3 dosing for peginterferon lambda-1a in chronic hepatitis C, Part 1: Modeling optimal treatment duration and sustained virologic response rates.

Peginterferon lambda-1a (Lambda) is under clinical development for the treatment of chronic hepatitis B and C virus (HBV, HCV, respectively) infection. This is the first of two manuscripts detailing the pharmacodynamic derivation of Lambda dosing and treatment durations for Phase 3 studies in HCV, based on Phase 2 data. We describe here the derivation of a population model of Lambda exposure; the adaptation of a previously published viral dynamic model for Lambda treatment and host genotype, and its use to simulate sustained virologic responses (SVR). Lambda population pharmacokinetics was described by a one-compartment model with first-order absorption, and 33.0 L per day clearance with 47% interindividual (36% intra-individual) variability. Weight explained a negligible proportion of the variability. Based on SVR predictions, optimum treatment durations were 48 weeks for HCV genotypes 1 or 4 (SVR estimates for 120, 180, and 240 µg Lambda: 58%, 54%, 47%, respectively) and 24 weeks for genotypes 2 or 3 (75%, 72%, 67%). SVR predictions for 240 µg were lower due to dropout predictions. The SVR model established the optimum treatment duration for Phase 3 studies but did not differentiate between 120 and 180 µg dosing. A companion manuscript describes dose selection based on exposure-response/safety modeling.

A first-generation multi-functional cytokine for simultaneous optical tracking and tumor therapy.

Creating new molecules that simultaneously enhance tumor cell killing and permit diagnostic tracking is vital to overcoming the limitations rendering current therapeutic regimens for terminal cancers ineffective. Accordingly, we investigated the efficacy of an innovative new multi-functional targeted anti-cancer molecule, SM7L, using models of the lethal brain tumor Glioblastoma multiforme (GBM). Designed using predictive computer modeling, SM7L incorporates the therapeutic activity of the promising anti-tumor cytokine MDA-7/IL-24, an enhanced secretory domain, and diagnostic domain for non-invasive tracking. In vitro assays revealed the diagnostic domain of SM7L produced robust photon emission, while the therapeutic domain showed marked anti-tumor efficacy and significant modulation of p38MAPK and ERK pathways. In vivo, the unique multi-functional nature of SM7L allowed simultaneous real-time monitoring of both SM7L delivery and anti-tumor efficacy. Utilizing engineered stem cells as novel delivery vehicles for SM7L therapy (SC-SM7L), we demonstrate that SC-SM7L significantly improved pharmacokinetics and attenuated progression of established peripheral and intracranial human GBM xenografts. Furthermore, SC-SM7L anti-tumor efficacy was augmented in vitro and in vivo by concurrent activation of caspase-mediated apoptosis induced by adjuvant SC-mediated S-TRAIL delivery. Collectively, these studies define a promising new approach to treating highly aggressive cancers, including GBM, using the optimized therapeutic molecule SM7L.

Preclinical safety, pharmacokinetics, and pharmacodynamics of recombinant human interleukin-21 in cynomolgus macaques (Macaca fascicularis).

Interleukin-21 (IL-21), a pleiotropic immunostimulatory type I cytokine, has anticancer effects in animal models. Preclinical studies designed to assess the safety of recombinant human IL-21 (rIL-21) for use in phase I oncology studies are described. The rIL-21 (≤3.0 mg/kg per dose) was given intravenously to cynomolgus monkeys (Macaca fascicularis) once daily for 5 days, followed by 9 nondosing days (1 cycle) for ≤4 cycles. The rIL-21 pharmacokinetics was dose-dependent. Accumulation was not observed after repeated dosing, consistent with the short elimination half-life (t (1/2,λz); 0.4-0.8 hours). Safety findings included cyclical anemia and thrombocytopenia, clinical pathology changes consistent with acute-phase response, leukocyte infiltrates in hepatic sinusoids, and sporadic serum transaminase elevations (typically <3 times upper-limit of normal); all were reversible upon cessation of treatment. Decreased pharmacodynamic responses with time corresponded to the development of anti-rIL-21 antibodies; effects varied among individuals and were dose-dependent. These studies demonstrated rIL-21 to be generally well-tolerated when administered to cynomolgus monkeys, and all adverse effects were reversible upon treatment cessation. However, development of anti-rIL-21 antibodies may limit the use of this species in long-term studies.

Pharmacokinetics and pharmacodynamics of pegylated interferon lambda-1 in cynomolgus monkeys.

Type III lambda interferons (IFNs) have activity similar to type I IFNs, but a more restricted receptor distribution. A pegylated human IFN lambda-1 (pegIFNλ) is under development for chronic hepatitis C. Induction of receptor signaling (STAT1 phosphorylation) and expression of interferon-stimulated genes (ISGs) by pegIFNλ were assessed in, respectively, cynomolgus monkey leukocyte subsets and hepatocytes stimulated in vitro. ISG induction by pegIFNλ or IFNα was also assessed in peripheral leukocytes and liver biopsies after single and repeat (x3) dosing of pegIFNλ (0.03, 0.3, 3.0 mg/kg) or unpegylated IFNα-2b (10(7) IU/kg). Single-dose pharmacokinetics of pegIFNλ were evaluated. Strong ISG induction occurred in cultured hepatocytes and liver biopsies with both pegIFNλ and IFNα. However, STAT1 phosphorylation, MHC class 1 upregulation, and ISG induction in leukocytes only occurred with IFNα. Serum neopterin was unaffected by pegIFNλ; however, ß-2-microglobulin was elevated at all doses. The terminal half-life of pegIFNλ was 23 h with a 59 mL/kg volume of distribution, consistent with other pegylated IFNs. Serum exposure was dose-proportional across the dosing range. These data demonstrate the suitability of cynomolgus monkeys for the preclinical evaluation of pegIFNλ. Additionally, the absence of pegIFNλ pharmacologic activity in leukocytes is consistent with its low receptor expression in blood.

An integrated disease/pharmacokinetic/pharmacodynamic model suggests improved interleukin-21 regimens validated prospectively for mouse solid cancers.

Interleukin (IL)-21 is an attractive antitumor agent with potent immunomodulatory functions. Yet thus far, the cytokine has yielded only partial responses in solid cancer patients, and conditions for beneficial IL-21 immunotherapy remain elusive. The current work aims to identify clinically-relevant IL-21 regimens with enhanced efficacy, based on mathematical modeling of long-term antitumor responses. For this purpose, pharmacokinetic (PK) and pharmacodynamic (PD) data were acquired from a preclinical study applying systemic IL-21 therapy in murine solid cancers. We developed an integrated disease/PK/PD model for the IL-21 anticancer response, and calibrated it using selected "training" data. The accuracy of the model was verified retrospectively under diverse IL-21 treatment settings, by comparing its predictions to independent "validation" data in melanoma and renal cell carcinoma-challenged mice (R(2)>0.90). Simulations of the verified model surfaced important therapeutic insights: (1) Fractionating the standard daily regimen (50 µg/dose) into a twice daily schedule (25 µg/dose) is advantageous, yielding a significantly lower tumor mass (45% decrease); (2) A low-dose (12 µg/day) regimen exerts a response similar to that obtained under the 50 µg/day treatment, suggestive of an equally efficacious dose with potentially reduced toxicity. Subsequent experiments in melanoma-bearing mice corroborated both of these predictions with high precision (R(2)>0.89), thus validating the model also prospectively in vivo. Thus, the confirmed PK/PD model rationalizes IL-21 therapy, and pinpoints improved clinically-feasible treatment schedules. Our analysis demonstrates the value of employing mathematical modeling and in silico-guided design of solid tumor immunotherapy in the clinic.

Safety and clinical effect of subcutaneous human interleukin-21 in patients with metastatic melanoma or renal cell carcinoma: a phase I trial.

PURPOSE: This phase I study in patients with metastatic melanoma (MM) and renal cell carcinoma (RCC) evaluated the safety and maximum tolerated dose (MTD), pharmacokinetics, pharmacodynamics, and preliminary antitumor activity of s.c. treatment of human recombinant interleukin 21 (IL-21). EXPERIMENTAL DESIGN: Phase I dose-escalation trial with treatment of three to six patients at each dose level, escalating from 3 to 300 µg/kg. Treatment was administered s.c. on an outpatient basis 3 days per week for 8 or 16 weeks. RESULTS: Twenty-six patients entered the study. Recombinant IL-21 was generally well tolerated, and dose-limiting toxicities (DLT) were first seen at dose levels of 200 and 300 µg/kg. The following four DLTs were observed in three patients: increased transaminases, increased hyperbilirubinemia, hypersensitivity reaction, and lethargy. The MTD was declared to be 200 µg/kg, although five of seven patients at the 300 µg/kg dose level experienced no DLTs. A treatment-related effect on soluble CD25 was observed at all dose levels and increased with dose level. Furthermore, higher doses induced interferon-γ, perforin, and granzyme B mRNA expression in peripheral blood, and granzyme B protein expression in both CD8(+) T cells and natural killer cells, consistent with the activation of cytotoxic lymphocytes. Three patients, one patient with MM and two with RCC, obtained a partial response. CONCLUSION: Outpatient treatment with s.c. administered IL-21 was tolerated and had dose-dependent pharmacodynamics. rIL-21 showed antitumor activity in patients with MM and RCC.

Phase I study of recombinant interleukin-21 in patients with metastatic melanoma and renal cell carcinoma.

PURPOSE: A phase I study of patients with metastatic malignant melanoma (MM) and renal cell carcinoma (RCC) evaluated the safety and maximum tolerated dose (MTD), pharmacokinetics, pharmacodynamics, and preliminary antitumor activity of recombinant human interleukin-21 (rIL-21). PATIENTS AND METHODS: Patients who had one or fewer prior systemic treatments for metastatic MM or RCC were treated with rIL-21 administered for two 5-day cycles on days 1 through 5 and 15 through 19 of a treatment course; rIL-21 was administered by rapid intravenous infusion in an outpatient setting. Cohorts of patients received doses ranging from 3 to 100 microg/kg/dose, and an expanded cohort was treated at the MTD. Patients with stable disease (SD) or better could receive additional treatment cycles. RESULTS: Forty-three patients were treated (24 MM; 19 RCC), including 28 in the expanded cohort. Dose-limiting toxicities consisted primarily of transient grade 3 laboratory abnormalities. The MTD was estimated to be 30 microg/kg. The most common adverse events included flu-like symptoms, pruritus, and rash. Twelve patients received up to five additional two-cycle courses of treatment without cumulative toxicity, except for one patient with reversible grade 4 hepatotoxicity. Serum concentrations of rIL-21 increased in a dose-proportional manner. Dose-dependent increases in soluble CD25 reflected lymphocyte activation. Antitumor activity was observed in both MM (one complete response and 11 SD) and RCC (four partial responses, 13 SD). CONCLUSION: Outpatient therapy with rIL-21 at 30 microg/kg was well tolerated, had dose-dependent pharmacokinetics and pharmacodynamics, and was associated with antitumor activity in patients with MM and RCC.

Efectos vasculares y moleculares de los andrógenos endógenos en un modelo experimental en conejos ateroscleróticos / Vascular and molecular effects of endogenous androgens in an atherosclerotic experimental rabbit model

Introducción. Existe controversia acerca de los efectos de los andrógenos sobre la aterosclerosis y sus manifestaciones clínicas. El objetivo de este trabajo fue comparar, en conejos ateroscleróticos castrados y no castrados, las características morfológicas, funcionales y la expresión de genes asociados con el metabolismo reverso del colesterol. Métodos. Cuarenta conejos machos NZ fueron distribuidos en 4 grupos: 1: no castrados, con dieta normal; 2: castrados, con dieta normal; 3: no castrados, con dieta aterogénica, y 4: castrados, con dieta aterogénica. En cada conejo se realizaron mediciones de colesterol total, testosterona libre, relajación vascular in vitro, análisis histomorfométricos de la aorta torácica, y la expresión de genes IL-1b, LRX-a y ABCA1. Resultados. La castración redujo los valores de testosterona total (2,1 ± 0,3 frente a 0,8 ± 0,4 ng/ml; p = 0,024). En animales con dieta normal (grupos 1 y 2), la castración incrementó la expresión de IL-1b (0,71 ± 0,07 frente a 0,77 ± 0,06; p < 0,001), redujo LXR-a (0,77 ± 0,008 frente a 0,41 ± 0,01; p < 0,001) y aumentó ABCA1 (0,2 ± 0,008 frente a 0,31 ± 0,08; p < 0,001). En animales con dieta aterogénica (grupos 3 y 4), la castración se asoció a mayor área de la placa (0,9 ± 1,3 frente a 2,6 ± 2,3 mm2; p = 0,026), índice área placa/área vaso (0,08 ± 0,1 frente a 0,25 ± 0,1; p < 0,001), índice área placa/área de la media (0,2 ± 0,2 frente a 0,4 ± 0,3; p = 0,003), mayor expresión de IL-1b (0,93 ± 0,05 frente a 1,1 ± 0,02; p < 0,001), reducción de LXR-a (1,45 ± 0,01 frente a 1,29 ± 0,01; p < 0,001) y reducción de ABCA1 (0,22 ± 0,1 frente a 0,20 ± 0,02; p < 0,001). Conclusiones. Este estudio demuestra que, en presencia de aterosclerosis inducida por hipercolesterolemia, la testosterona endógena podría tener un efecto atenuante o protector de la aterogénesis (AU)

Introduction. The effects of androgens on atherosclerosis and its clinical manifestations are controversial. The objective of this study was to compare the morphologic and functional characteristics and gene expression associated with reverse metabolism of cholesterol in castrated and non-castrated atherosclerotic rabbits. Methods. Forty male NZ rabbits were distributed in four groups: 1: non-castrated with a normal diet; 2: castrated with a normal diet; 3: non-castrated with an atherogenic diet, and 4: castrated with an atherogenic diet. Measurements of total cholesterol, free testosterone, in vitro vascular relaxation, histomorphometric analyses of the thoracic aorta and expression of the IL-1b, LRX-a and ABCA1 genes were carried out in each rabbit. Results. Castration decreased levels of total testosterone (2.1 ± 0.3 vs. 0.8 ± 0.4 ng/mL; P=.024). In animals with a normal diet (groups 1 and 2), castration increased expression of IL-1b (0.71 ± 0.07 vs. 0.77 ± 0.06; P<.001), decreased that of LXR-a (0.77 ± 0.008 vs. 0.41 ± 0.01; P<.001) and increased that of ABCA1 (0.2±0.008 vs. 0.31±0.08; P<.001). In animals with an atherogenic diet (groups 3 and 4), castration was associated with a larger plaque area (0.9 ± 1.3 vs. 2.6 ± 2.3 mm2; P=.026), plaque area/vessel area ratio (0.08 ± 0.1 vs. 0.25 ± 0.1; P<.001), plaque area/media area ratio (0.2 ± 0.2 vs. 0.4 ± 0.3; P=.003), greater expression of IL-1b (0.93 ± 0.05 vs. 1.1 ± 0.02; P<.001), reduction of LXR-a (1.45 ± 0.01 vs. 1.29 ± 0.01; P<.001), and reduction of ABCA1 (0.22 ± 0.1 vs. 0.20 ± 0.02; P<.001). Conclusions. This study shows that in the presence of atherosclerosis induced by hypercholesterolemia, endogenous testosterone could have an attenuating or protective effect on atherogenesis (AU)

Drug interaction studies of therapeutic proteins or monoclonal antibodies.

Drug interactions can alter the pharmacokinetics and/or pharmacodynamics of a drug. In pharmacokinetic drug interactions, the concentrations of 1 or more drugs are altered by another. This change in concentration in a given drug may be due to changes in absorption, distribution, metabolism, or elimination. The pharmacodynamic interaction can lead to additive, synergistic, or antagonistic effects of a drug. Drug interaction studies are regularly conducted with conventional drugs (small molecules), but very few drug interaction studies have been performed with macromolecules (therapeutic proteins or monoclonal antibodies). This is mainly because most macromolecules are not metabolized by the cytochrome P450 system, and their mechanism of elimination is complex. However, it has been shown in several studies that interferons can have an impact on the cytochrome P450 system that may alter the pharmacokinetics and pharmacodynamics of a conventional drug when given with interferons. Therefore, it is important to evaluate the effect of other classes of macromolecules (cytokines, interleukins, monoclonal antibodies) on drug-metabolizing enzymes. It is also imperative that the effects of conventional drugs on the pharmacokinetics and pharmacodynamics of macromolecules be conducted. The present review encompasses several drug interaction studies that were conducted with macromolecules and highlights the impact of these studies on the pharmacokinetics and/or pharmacodynamics of the involved drugs.

An open-label, two-arm, phase I trial of recombinant human interleukin-21 in patients with metastatic melanoma.

PURPOSE: Human interleukin-21 (IL-21) is a pleiotropic class I cytokine that activates CD8(+) T cells and natural killer cells. We report a phase 1 study of recombinant human IL-21 in patients with surgically incurable metastatic melanoma. The primary objective was to investigate safety and tolerability by determining dose-limiting toxicity (DLT). The secondary objectives were to identify a dose response for various biomarkers in the peripheral blood, estimate the minimum biologically effective dose, determine the pharmacokinetics of IL-21, determine if anti-IL-21 antibodies were induced during therapy, and measure effects on tumor size according to Response Evaluation Criteria in Solid Tumors. EXPERIMENTAL DESIGN: Open-label, two-arm, dose escalation trial of IL-21 administered by i.v. bolus injection at dose levels from 1 to 100 microg/kg using two parallel treatment regimens: thrice weekly for 6 weeks (3/wk) or three cycles of daily dosing for 5 days followed by 9 days of rest (5+9). RESULTS: Twenty-nine patients entered the study. IL-21 was generally well tolerated and no DLTs were observed at the 1, 3, and 10 microg/kg dose levels. In the 3/wk regimen, DLTs were increased in alanine aminotransferase, neutropenia, and lightheadedness with fever and rigors. DLTs in the 5+9 regimen were increased in aspartate aminotransferase and alanine aminotransferase, neutropenia, fatigue, and thrombocytopenia. The maximum tolerated dose was declared to be 30 microg/kg for both regimens. Effects on biomarkers were observed at all dose levels, including increased levels of soluble CD25 and up-regulation of perforin and granzyme B mRNA in CD8(+) cells. One partial tumor response observed after treatment with IL-21 for 2 x 6 weeks (3/wk) became complete 3 months later. CONCLUSIONS: IL-21 is biologically active at all dose levels administered and is generally well tolerated, and phase 2 studies have commenced using 30 microg/kg in the 5+9 regimen.

Pharmacodynamic model of interleukin-21 effects on red blood cells in cynomolgus monkeys.

Interleukin-21 (IL-21) is a novel cytokine that is currently under clinical investigations as a potential anti-cancer agent. Like many other anti-cancer agents, including other interleukins, IL-21 is seen to produce a broad range of biological effects that may be related to both efficacy and safety of treatment. The present analysis investigates the observed pharmacodynamics effects on red blood cells following various treatment schedules of human IL-21 administrated to cynomolgus monkeys. These effects are described by a novel non-linear mixed-effects model that enabled separation of drug effects and sampling effects, the latter believed to be due partly to blood loss and partly to stress induced haemolysis in connection with blood sampling. Two different studies with a total of 9 different treatment groups of cynomolgus monkeys were used for model development. In conclusion, the model describes the IL-21 induced drop in red blood cells to be (1) caused by removal rather than suppression of production, consistent with increased reticulocyte concentration, and (2) considerably delayed compared to dosing, i.e. not related to the drop in red blood cells observed immediately post dose. It is believed that the structural model presented here can be used for other types of drug induced loss of red blood cells, whereas the mechanism for sampling related blood loss is relevant for investigations of anaemia in all pharmacological studies with smaller animals.