Small Molecule CD38 Inhibitors: Synthesis of 8-Amino-N1-inosine 5′-monophosphate, Analogues and Early Structure-Activity Relationship

Although a monoclonal antibody targeting the multifunctional ectoenzyme CD38 is an FDA-approved drug, few small molecule inhibitors exist for this enzyme that catalyzes inter alia the formation and metabolism of the N1-ribosylated, Ca2+-mobilizing, second messenger cyclic adenosine 5′-diphosphoribose (cADPR). N1-Inosine 5′-monophosphate (N1-IMP) is a fragment directly related to cADPR. 8-Substituted-N1-IMP derivatives, prepared by degradation of cyclic parent compounds, inhibit CD38-mediated cADPR hydrolysis more efficiently than related cyclic analogues, making them attractive for inhibitor development. We report a total synthesis of the N1-IMP scaffold from adenine and a small initial compound series that facilitated early delineation of structure-activity parameters, with analogues evaluated for inhibition of CD38-mediated hydrolysis of cADPR. The 5′-phosphate group proved essential for useful activity, but substitution of this group by a sulfonamide bioisostere was not fruitful. 8-NH2-N1-IMP is the most potent inhibitor (IC50 = 7.6 μM) and importantly HPLC studies showed this ligand to be cleaved at high CD38 concentrations, confirming its access to the CD38 catalytic machinery and demonstrating the potential of our fragment approach.

Serum TNF-α Level as a Possible Predictor of Inhibitor Levels in Severe Hemophilia A

Background. The development of factor VIII (FVIII) inhibitor in patients with hemophilia A (PWHA) is a great challenge for hemophilia care. Both genetic and environmental factors led to complications in PWHA. The development of inhibitory antibodies is usually induced by the immune response. Tumor necrosis factor α (TNF-α), one of the cytokines, might contribute to its polymorphism. In this study, we investigated the clinical factors, level of serum TNF-α, and polymorphism of c . − 308 G > A TNF − α gene in inhibitor development in severe PWHA. Methods. A cross-sectional study was conducted among all PWHA in West Java province. The clinical parameters, FVIII, FVIII inhibitor, and serum TNF-α level were assessed. The genotyping of − 380 G > A TNF-α gene polymorphism was performed using polymerase chain reaction and Sanger sequencing. Results. Among the 258 PWHA, 216 (83.7%) were identified as severe PWHA. The FVIII inhibitor was identified in 90/216 (41.6%) of severe PWHA, consisting of 45 high-titer inhibitors (HTI) and 45 low-titer inhibitors (LTI). There was a significant correlation between serum TNF-α level and the development of HTI ( p = 0.043 ). The cutoff point of serum TNF-α level, which can be used to differentiate between HTI and LTI, was 11.45 pg/mL. The frequency of FVIII replacement therapy was significant only in HTI of severe PWHA regarding serum TNF-α level ( p = 0.028 ). There is no correlation between polymorphisms of − 380 G > A TNF-α gene and inhibitor development ( p = 0.645 ). Conclusions. The prevalence of FVIII inhibitor in severe PWHA in West Java, Indonesia, was 41.6%. The frequency of replacement therapy is a risk factor for inhibitor development. Serum TNF-α level might be used to differentiate between high and low inhibitor levels in severe hemophilia A, and this might support decision making regarding treatment options for inhibitor in severe hemophilia A.

Factor VIII Epitope Analysis Using a Random Peptide Phage-Display Library Approach in the Sippet Cohort

Background Inhibitor development is the most severe complication of hemophilia A care, and is associated with increased morbidity and mortality. Aims The aim of this study was to use a novel epitope mapping method to explore the factor VIII (FVIII)-specific epitope profile in the SIPPET cohort population. Methods The population consisted of 122 previously untreated patients with severe hemophilia A that were followed-up for 50 days of exposure to FVIII. Sampling was performed before FVIII treatment and at the end of the follow-up. The outcome was inhibitor development. The FVIII-specific IgG epitope repertoire was assessed by means of a novel high-throughput epitope mapping technique using a random peptide phage-display library. Using this assay, a set of affinity-selected 12-mer peptide sequences (also called mimotopes) that were strongly bound by FVIII-specific antibodies were identified. These mimotopes were clustered on the basis of sequence similarity and a consensus motif was generated for each mimotope cluster. Discriminative performance of these mimotope clusters was assessed by ROC analysis. Mimotope clusters were mapped onto the 3D structure of a B-domain deleted FVIII model using a B-cell epitope prediction algorithm (Mapitope). Results The FVIII-specific antibody response is polyclonal with several mimotope clusters. The most predominant mimotope clusters in inhibitor patients were mapped to the heavy chain of the FVIII molecule. Using plasma samples taken before exposure to FVIII, three mimotopes (with the consensus motifs "QM", "PSLxWK" and "SWPHxxxxK") were identified that predicted inhibitor development (with an AUC of 0.76, 0.80 and 0.76 respectively). Conclusion Information on immunodominant epitope clusters can be used to generate novel, less immunogenic FVIII proteins and set up diagnostic tests that predict the risk of inhibitor development before starting treatment with FVIII. Figure 1 Figure 1. Disclosures Palm: Protobios LLC: Current Employment, Patents & Royalties: Inventor of the patent application (PCT Application No. US/14079626) filed by Protobios that covers the use of phage display method to manipulate and monitor humoral immunity.. Palla: Pfizer: Other: Travel support; Kedrion: Other: Travel support; Novonordisk: Speakers Bureau. Peyvandi: Roche: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Sobi: Consultancy, Honoraria; Takeda: Consultancy, Honoraria.

An Individualized Approach to Treating Pups with Severe Hemophilia a: Which Factors Correlate with the Low Rate of Inhibitor Development?

Introduction:Development of inhibitors to replacement factor VIII (FVIII) remains a significant challenge to the management of previously untreated patients (PUPs) with severe hemophilia A. Although several determinants have been associated with the risk of inhibitor development, the impact of treatment approach remains controversial. Here we report our experience with an individualized approach to managing PUPs at a single hemophilia treatment center (HTC) in Germany. Methods:PUPs with severe hemophilia A (FVIII:C <1%) treated at the Gerinnungszentrum Rhein-Ruhr (GZRR), Germany, between January 2013 and June 2021 were followed prospectively. Our treatment approach includes early prophylactic physiotherapy, pdFVIIIconcentrate for at least the first 50 exposure days (EDs), tailored prophylaxis with individualized dose escalation according to bleeding tendency, and avoidance of prolonged on-demand treatment by avoiding treatment of minor bleeds or hematomas. Potential bleeds were examined by a hemophilia specialist and a decision made as whether to treat with pdFVIII based on the bleed location and severity. Ultrasound was performed every 3-6 months to check for joint bleeds. Where on-demand treatment was necessary, we used a high initial dose of 60-80 IU/kg with the aim of reducing the need for subsequent doses. Non-urgent surgical procedures were postponed and venous access system implants were avoided within the first 100 EDs. Inhibitor levels were measured using the modified Bethesda assay every 3-4 EDs until ED 100, and every 3 months thereafter for 2 years. Results:Data from 28 consecutive caucasian PUPs were collected. Fourteen (50%) patients had a F8 gene mutation associated with a high risk for inhibitor development. At the time of data cut-off 23 patients had received over 50 EDs of FVIII treatment, with 21 patients having over 100 EDs; the remaining patients had up to 45 EDs.Of the 28 patients, 27 started prophylaxis within the first 10 EDs. The initial prophylaxis schedule was tailored to each patient and ranged from 21 IU/kg every 10 days up to 40 IU/kg twice per week. One patient was treated on-demand for an intracranial bleed from ED 1-100. Only 3 spontaneous bleeds in 3 patients were treated; 25 patients (89%) remained free of spontaneous bleeds during prophylaxis. All three spontaneous bleeds were treated successfully with FVIII ± tranexamic acid. None of the 28 patients developed inhibitors. Discussion:Our approach to managing PUPs includes treatment with pdFVIII for at least the first 50 EDs, during which we treat bleeds only where necessary and use high doses to minimize further infusions. We had no cases of inhibitor development in our prospective cohort of 28 patients. In contrast, between 2003 and 2012, four of nine (44%) PUPs treated at our center developed inhibitors during the first 20 EDs, with two patients developing low-titer and two high-titer inhibitors. At that time we used recombinant FVIII (rFVIII) for prophylaxis in most patients and were less selective about which bleeds to treat with FVIII. Our individualized management approach, choice of pdFVIII and restricted use of FVIII for on-demand treatment therefore appear to correlate with a reduction in inhibitor incidence at our center. We usually switch patients from pdFVIII to rFVIII after at least 50 EDs due to the lower administration volume. Given the low rate of inhibitor development reported for PUPs treated with human cell line-derived rFVIII, there is a rationale to consider starting PUPs on human cell line-derived rFVIII. Conclusion:Our data support the position, that the use of an individualized management approach minimizes the risk of inhibitor development and raise important questions about how different aspects of treatment approach could impact outcomes in PUPs with severe hemophilia A. Disclosures No relevant conflicts of interest to declare.

Immunogenicity, Efficacy and Safety of Rurioctocog Alfa Pegol in Previously Untreated Patients with Severe Hemophilia a: Interim Results from an Open-Label Multicenter Clinical Trial

Background Management of severe hemophilia A includes on-demand treatment or prophylaxis with replacement factor VIII (FVIII) concentrate. FVIII inhibitors can develop following exposure to exogenous FVIII in approximately 30% of previously untreated patients (PUPs), typically in the first 50 exposure days (EDs), with serious complications. This is the first study evaluating the safety, immunogenicity, and hemostatic efficacy of rurioctocog alfa pegol (Adynovate ®; Baxalta US Inc., a Takeda company, Lexington, MA, USA), an extended half-life (EHL) recombinant FVIII, in PUPs with severe hemophilia A. Methods This prospective, open-label, multi-center, phase 3 study (NCT02615691) was conducted in patients ˂6 years of age with severe hemophilia A (FVIII <1%). Patients were previously untreated, or had <3 EDs to rurioctocog alfa pegol, octocog alfa, or plasma transfusion at any time prior to screening. Patients with detectable FVIII inhibitory antibodies at screening or a history of FVIII inhibitory antibodies prior to screening (≥0.6 Bethesda units) were not eligible. Patients received intravenous rurioctocog alfa pegol as prophylaxis (25-50 IU/kg, up to 80 IU/kg ≥1 × weekly) and/or on-demand therapy (10-50 IU/kg, up to 80 IU/kg depending on bleed severity). Prophylaxis was started before 3 years of age or after a maximum of 2 joint bleeds, whichever occurred first. The primary endpoint was the incidence of FVIII inhibitor development. Secondary endpoints included safety and efficacy (annualized bleeding rate [ABR] and hemostatic efficacy). This protocol-specified interim analysis was conducted after 50 patients had completed ≥50 EDs without developing an inhibitor to FVIII or had developed a confirmed FVIII inhibitor at any time. The data cut-off was 30 August 2019. Demographic and baseline characteristics were summarized using continuous and categorical data. The incidence of FVIII inhibitor development was calculated using the Clopper Pearson exact 95% CI computed for the proportion of patients who developed FVIII inhibitors during the study. ABR was analyzed by point and interval estimates derived from a negative binomial model with treatment regimen as a covariate. The number and percentage of patients reporting adverse events (AEs) and serious AEs (SAEs) was recorded for all patients receiving rurioctocog alfa pegol. Informed consent and ethics approval were obtained. Results As of the data cut-off, 59 (73.8%) of 80 enrolled patients had received ≥1 dose of rurioctocog alfa pegol; 18 patients (screen failures) did not meet the eligibility criteria and 4 discontinued prior to treatment. 54 patients received prophylaxis and 35 received on-demand treatment at any time during the study period. The mean (SD) patient age at baseline was 11.8 (8.2) months. The number of patients with 0 EDs prior to screening was 36 (61.0%), with 9 (15.3%) patients having 1 ED and 14 (23.7%) having 2 EDs. Overall, 32 patients had a family history of hemophilia A. A large deletion, intron 1 or intron 22 inversion, or substitution nonsense hemophilia gene mutation was present in 29 (49.2%) patients and 21 (35.6%) had either a small deletion, small duplication, or substitution missense gene mutation. Of the 52 patients who qualified for this interim analysis, 10 developed an inhibitory antibody to rurioctocog alfa pegol during the study; the incidence of inhibitor development was 0.192 (95% CI, 0.096-0.325) (10/52). Rurioctocog alfa pegol exposure data and ABRs for patients receiving prophylaxis or on-demand treatment are presented in Table 1. At bleed resolution, hemostatic efficacy was rated by patients as "excellent" for 88/269 bleeds (32.7%) and "good" for 73/269 bleeds (27.1%). Overall, 52 (88.1%) patients receiving rurioctocog alfa pegol experienced a total of 283 AEs, and 13 patients experienced 14 rurioctocog alfa pegol-related AEs (including 10 SAEs). SAEs occurred in 24 patients, 10 of whom experienced 10 treatment-related SAEs of FVIII inhibitor development. Discussion This is the first prospective study of the EHL recombinant FVIII rurioctocog alfa pegol for the treatment of PUPs with severe hemophilia A. These preliminary results demonstrate a relatively low inhibitor rate compared with other EHL recombinant FVIII products and a safety and efficacy profile consistent with that previously observed for rurioctocog alfa pegol in the treatment of bleeding episodes in patients with hemophilia A. Figure 1 Figure 1. Disclosures Sidonio: Guardian Therapeutics: Consultancy; Pfizer: Consultancy; Bayer: Consultancy; Octapharma: Consultancy, Research Funding; Novo Nordisk: Consultancy; Biomarin: Consultancy; Genentech: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Catalyst: Consultancy. Peyvandi: Takeda: Honoraria; Spark: Honoraria; Sobi: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Roche: Honoraria; Bioverativ: Honoraria; Grifols: Honoraria. Stasyshyn: Octapharma: Consultancy, Research Funding, Speakers Bureau; Pfizer: Consultancy, Research Funding, Speakers Bureau; CSL Behring: Consultancy, Research Funding; Shire: Consultancy; Grifols: Consultancy, Speakers Bureau; Takeda: Consultancy, Research Funding, Speakers Bureau; Novo Nordisk: Consultancy, Research Funding, Speakers Bureau. Antmen: Takeda: Consultancy; Pfizer: Consultancy; Roche: Consultancy; Novo Nordisk: Consultancy. Yeoh: Takeda: Honoraria; Pfizer: Honoraria; Roche: Honoraria; Grifols: Honoraria. Maggiore: IQVIA: Current Employment. Engl: Baxalta Innovations GmbH, a Takeda company: Current Employment; Takeda: Current equity holder in publicly-traded company. Allen: Takeda Development Center Americas, Inc.: Current Employment; Takeda: Current equity holder in publicly-traded company. Tangada: Takeda: Current equity holder in publicly-traded company; Takeda Development Center Americas, Inc: Current Employment.

A study on catalytic and non-catalytic sites of H5N1 and H1N1 neuraminidase as the target for chalcone inhibitors

The H1N1 pandemic in 2009 and the H5N1 outbreak in 2005 have shocked the world as millions of people were infected and hundreds of thousands died due to the infections by the influenza virus. Oseltamivir, the most common drug to block the viral life cycle by inhibiting neuraminidase (NA) enzyme, has been less effective in some resistant cases due to the virus mutation. Presently, the binding of 10 chalcone derivatives towards H5N1 and H1N1 NAs in the non-catalytic and catalytic sites was studied using molecular docking. The in silico study was also conducted for its drug-like likeness such as Lipinski Rule, mutagenicity, toxicity and pharmacokinetic profiles. The result demonstrates that two chalcones (1c and 2b) have the potential for future NA inhibitor development. Compound 1c inhibits H5N1 NA and H1N1 NA with IC50 of 27.63 µM and 28.11 µM, respectively, whereas compound 2b inhibits NAs with IC50 of 87.54 µM and 73.17 µM for H5N1 and H1N1, respectively. The in silico drug-like likeness prediction reveals that 1c is 62% better than 2b (58%) in meeting the criteria. The results suggested that 1c and 2b have potencies to be developed as non-competitive inhibitors of neuraminidase for the future development of anti-influenza drugs.

Patient preferences in the treatment of hemophilia A: A latent class analysis

Objective To examine subgroup-specific treatment preferences and characteristics of patients with hemophilia A. Methods Best–Worst Scaling (BWS) Case 3 (four attributes: application type; bleeding frequencies/year; inhibitor development risk; thromboembolic events of hemophilia A treatment risk) conducted via online survey. Respondents chose the best and the worst option of three treatment alternatives. Data were analyzed via latent class model (LCM), allowing capture of heterogeneity in the sample. Respondents were grouped into a predefined number of classes with distinct preferences. Results The final dataset contained 57 respondents. LCM analysis segmented the sample into two classes with heterogeneous preferences. Preferences within each were homogeneous. For class 1, the most decisive factor was bleeding frequency/year. Respondents seemed to focus mainly on this in their choice decisions. With some distance, inhibitor development was the second most important. The remaining attributes were of far less importance for respondents in this class. Respondents in class 2 based their choice decisions primarily on inhibitor development, also followed, by some distance, the second most important attribute bleeding frequency/year. There was statistical significance (P < 0.05) between the number of annual bleedings and the probability of class membership. Conclusions The LCM analysis addresses heterogeneity in respondents’ choice decisions, which helps to tailor treatment alternatives to individual needs. Study results support clinical and allocative decision-making and improve the quality of interpretation of clinical data.