BioCryst Pharmaceuticals Research Articles

POS-045 Evaluating BCX9930, an Oral Factor D Inhibitor for Treatment of Complement-Mediated Kidney Disease: A Proof-of-Concept Study (RENEW)

POS-045 Evaluating BCX9930, an Oral Factor D Inhibitor for Treatment of Complement-Mediated Kidney Disease: A Proof-of-Concept Study (RENEW)

POS-041 BCX9930, AN ORAL FACTOR D INHIBITOR, SUPPRESSES COMPLEMENT ALTERNATIVE PATHWAY ACTIVITY IN PATIENTS WITH COMPLEMENT 3 GLOMERULOPATHY

POS-041 BCX9930, AN ORAL FACTOR D INHIBITOR, SUPPRESSES COMPLEMENT ALTERNATIVE PATHWAY ACTIVITY IN PATIENTS WITH COMPLEMENT 3 GLOMERULOPATHY

A review of oral kallikrein inhibitor berotralstat for hereditary angioedema.

Orladeyo, a once-daily oral formulation of berotralstat (formerly BCX-7353), is a novel oral small-molecule drug developed by BioCryst Pharmaceuticals for the prevention of hereditary angioedema (HAE) attacks. It was first approved by the U.S. Food and Drug Administration (FDA) in 2020, and in 2021 also gained approval for marketing in Japan and the European Union. Preclinical and phase I studies showed promising efficacy and safety, and several multicenter international Angioedema Prophylaxis (APeX) phase II and III trials have since been initiated to further evaluate berotralstat. The ongoing phase III APeX-2 trial showed a 67% reduction in HAE attacks at the standard 150-mg dosing. Mild to moderate gastrointestinal side effects are most commonly seen and minimal serious adverse effects have been reported. Other first-line therapies for HAE prophylaxis rely on burdensome subcutaneous or intravenous routes. Thus far berotralstat has shown to be effective and well tolerated for HAE prophylaxis with the convenience of once-daily oral dosing.

A case of normal C1 esterase inhibitor hereditary angioedema successfully treated with berotralstat

A case of normal C1 esterase inhibitor hereditary angioedema successfully treated with berotralstat

Pozelimab, a Human Monoclonal Antibody Against Complement Factor C5, Provided Inhibition of Intravascular Hemolysis in Patients with Paroxysmal Nocturnal Hemoglobinuria

INTRODUCTIONParoxysmal Nocturnal hemoglobuinuria (PNH) is a rare, acquired, life-threatening disorder characterised by intravascular hemolysis and increased risk of thrombosis. Current available treatments represent a significant burden to patients and include anti-complement factor 5 (C5) therapies, eculizumab and ravulizumab, both intravenous infusions, or more recently, twice weekly C3 inhibitor, Pegcetacoplan, a subcutaneous (SC) infusion treatment.Pozelimab (REGN3918), a fully human monoclonal immunoglobulin G4 antibody directed against C5, has been shown to bind with high affinity to wild-type and variant (R885H/C) human C5 and block its activity.In a healthy volunteer study (NCT03115996), SC administration of pozelimab was found to be generally well tolerated while providing complete inhibition of ex vivo-assessed hemolytic activity [Weyne J et al. Blood. 2018;S1:1039]. The data suggested that pozelimab may provide control of intravascular hemolysis in patients with active PNH, and thus could provide an important new alternative for patients supporting progression to a first-in-patient study of pozelimab in patients with active PNH.OBJECTIVETo demonstrate a clinically significant reduction in intravascular hemolysis by once-weekly SC administration of pozelimab over 26 weeks of treatment in patients with active PNH.METHODSThis is a phase 2, open-label, single-arm, 26-week treatment study in 24 patients with active symptomatic PNH who are naïve to complement inhibitor therapy, or who have received prior treatment with a complement inhibitor but not within 6 months prior to the start of the study (NCT03946748).The treatment regimen consists of pozelimab as a single IV loading dose of 30 mg/kg followed thereafter by weekly SC 800 mg administrations.The effect of pozelimab on intravascular hemolysis (monitored via LDH levels) and transfusion avoidance, as well as safety, is to be assessed from baseline to week 26 (study day 183; only partial data were available for some patients at the time of abstract submission). Pozelimab pharmacodynamics was assessed utilizing a sheep red blood cell (RBC) complement activity assay (CH50) and rabbit RBC complement activity assay (AH50).RESULTSAll 24 patients completed the 26-week treatment period with no study drug discontinuation and have been enrolled into an ongoing open-label extension study (NCT04162470). An interim analysis on the first 17 patients was previously reported. All 17 patients had at least 71 days of treatment, with 10 patients receiving treatment for up to 183 days. All enrolled patients had baseline LDH levels ≥2 x upper limit of normal (ULN). Participants were enrolled in two cohorts: Cohort A for dose confirmation and Cohort B for further evaluation of efficacy and safety.Interim Efficacy AnalysisAs previously reported, treatment with pozelimab led to a rapid and sustained reduction in LDH through study week 26. All 17 patients achieved LDH reduction to below the clinically significant threshold of LDH ≤1.5 x ULN.All but one patient achieved control of intravascular hemolysis (LDH ≤1.5 x ULN) at week 2, and all but one patient achieved normalization of LDH (LDH ≤1.0 x ULN) at week 4.Importantly, one patient who is a carrier of a C5 variant known to be resistant to blockade by eculizumab/ravulizumab demonstrated rapid and sustained normalization of LDH.Interim SafetyAs previously reported, no serious adverse events or adverse events leading to treatment discontinuation were reported. Common treatment-emergent adverse events included headache (4 patients; 23.5%) and nausea (2 patients; 11.8%).No breakthrough hemolysis events were observed.CONCLUSIONSPozelimab administered SC once weekly led to the inhibition of intravascular hemolysis in patients with active PNH and was generally well-tolerated. An update to the previously reported interim analysis will be provided.Upon successful completion of the 26-week treatment period, patients are enrolled into an open-label extension study. DisclosuresWeyne: Regeneron Pharmaceuticals, Inc.: Current Employment, Current holder of stock options in a privately-held company. Chaudhari: Regeneron Pharmaceuticals, Inc.: Current Employment, Current holder of stock options in a privately-held company. Harari: Regeneron Pharmaceuticals, Inc.: Current Employment, Current holder of stock options in a privately-held company. Miller: Regeneron Pharmaceuticals, Inc.: Current Employment, Current holder of stock options in a privately-held company. Dain: Regeneron Pharmaceuticals, Inc.: Other: Contractor. Meagher: Regeneron Pharmaceuticals, Inc.: Current Employment, Current holder of stock options in a privately-held company. Rodgers: Regeneron Pharmaceuticals, Inc.: Current Employment, Current holder of stock options in a privately-held company. Perlee: Regeneron Pharmaceuticals, Inc.: Current Employment, Current holder of stock options in a privately-held company. Morton: Regeneron Pharmaceuticals, Inc.: Current Employment, Current holder of stock options in a privately-held company. Weinreich: Regeneron Pharmaceuticals, Inc.: Current Employment, Current holder of stock options in a privately-held company. Yancopoulos: Regeneron Pharmaceuticals, Inc.: Current Employment, Current holder of stock options in a privately-held company. Griffin: Alexion, AstraZeneca Rare Disease: Honoraria, Membership on an entity's Board of Directors or advisory committees; BioCryst Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sobi Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Apellis: Other: Educational grant support.

Characteristics and Outcomes of Newly Diagnosed Multiple Myeloma Patients with and without Extramedullary Disease after Autologous Transplant and Maintenance Therapy: A Study from the Cmwp-EBMT

Characteristics and Outcomes of Newly Diagnosed Multiple Myeloma Patients with and without Extramedullary Disease after Autologous Transplant and Maintenance Therapy: A Study from the Cmwp-EBMT

Propensity Score Matching Analysis Comparing Extracorporeal Photopheresis (ECP) Vs Best Available Therapy in Third Line or Later Treatment of Chronic Graft-Versus-Host Disease (cGVHD)

*DB and DK contributed to the work equallyBackgroundProspective randomized controlled data comparing extracorporeal photopheresis (ECP) to other treatments for chronic graft vs host disease (cGvHD) as third-line or later therapy are limited, despite its clinical benefit observed in patients (pts) who failed ≥ 2 lines of previous therapy. Our single-center experience has reported promising results, including 68.3% failure-free survival (FFS) and 85.9% overall survival (OS) at 12 months in 75 heavily pre-treated cGvHD pts treated with ECP (ASH 2021 Abstract ID 152640).The present study compared outcomes, using propensity-score matching (PSM), between ECP (“ECP group”, n=74) and a historical cohort treated with best available therapy (BAT) as third-line or later treatment from 2007 to 2021 (“BAT group”, n=132). Statistical endpoints such as FFS and OS, as well as steroid dose reduction were evaluated instead of overall response due to limited response assessment data available from retrospective chart review.Patients and methodsThe BAT group received MMF (n=71, 53.8%), prednisone (n=37, 28.0%), prednisone/cyclosporine (n=7, 5.3%), rituximab (n=7, 5.3%), and others (n=10, 7.6%). There was an imbalance in characteristics between the two groups, as expected; the ECP group had more pts with severe cGVHD (91.1% vs 20.5%; p<0.001), fewer with a previous history of acute GVHD (aGvHD: 60.8% vs 78.0%; p=0.008), and fewer on a prednisone dose ≥0.5mg/kg/day (37.8% vs. 90.5%; p<0.001). PSM analysis was applied to adjust risk factors imbalanced between groups, including cGVHD grade (mild/moderate vs severe), aGVHD history, and baseline prednisone dose (<0.5 vs. ≥ 0.5 mg/kg/day). A total of 54 pts (27 case-control pairs) were selected via PSM within 0.2 of a calliper difference, resulting in the balancing of risk factors between groups: cGVHD severity (p=0.941), aGVHD history (p=0.75) and prednisone dose ≥ 0.5 mg/kg/day (p=0.788).FFS and OS were calculated from the day of starting ECP or BAT, and were compared using Cox's hazard model. Daily prednisone dose at months 0, 3 and 6 were calculated divided by body weight (kg), and the proportions of pts on prednisone ≤ 0, 0.1, 0.2 and 0.5mg/kg/day were compared.ResultsIn the overall cohort (n=206), with a median 29 months of follow-up, 114 treatment failures (55.3%) occurred. While the non-relapse mortality (NRM) was similar in both groups, the ECP group showed a lower rate of resistance requiring therapy switch. Failure was noted in 27 ECP pts (36.4%) due to causes including resistance/intolerance requiring a switch to other therapy (n=15; 20.3%), NRM (n=11, 14.8%), and relapse (n=1; 1.4%), while 87 failures (65.9%) were noted in BAT pts due to resistance requiring a switch to other therapy (n=63; 47.7%), NRM (n=7; 5.3%), and relapse (n=17; 12.9%).In the overall cohort, the 12-month FFS was 68.3% and 32.0% in ECP and BAT groups (p<0.0001; Fig 1A), while OS was 86.2% and 82.2% in ECP and BAT groups, respectively (p=0.333; Fig 1B). In the PSM cohort (n=54), the ECP group showed a survival benefit at 12 months: FFS was 65.8% in the ECP group vs. 30.5% in the BAT group (p=0.00226; Fig 2A), and OS was 76.6% in the ECP group vs. 67.1% in the BAT group (p=0.0977; Fig 2B).Multivariate analysis in the PSM cohort confirmed that ECP was superior to BAT for FFS (p=0.024, HR 0.317 [0.117-0.859]) when adjusted for other risk factors including cGVHD severity, aGvHD history, age, HCT-CI score and prednisone dose ≤0.5mg/kg/day.Prednisone doses were gradually reduced over time; the median doses of prednisone at months 0, 3, and 6 were 0.35, 0.22 and 0.11 mg/kg/day, respectively, in the ECP group vs. 0.96, 0.24 and 0.19mg/kg/day in the BAT group. ECP also showed better kinetics of steroid dose reduction over time; the proportions of pts who discontinued prednisone at months 0, 3 and 6 were 16.2, 17.6% and 32.4% in ECP group vs. 0.8%, 0% and 2.5% in BAT group (Fig 3). The differences in the proportion of pts (delta) who discontinued prednisone in the ECP vs. BAT groups were 15.4%, 17.6% and 29.9% at 0, 3, and 6 months, respectively.ConclusionIn the current study using PSM analysis, use of ECP was associated with a superior FFS to BAT when used as third-line or later therapy in cGVHD patients who failed at least 2 lines of previous therapy. Use of ECP also allowed for better steroid tapering in comparison to BAT. [Display omitted] DisclosuresPatriquin: Alexion: Consultancy, Honoraria, Speakers Bureau; BioCryst Pharmaceuticals: Honoraria; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Apellis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria. Law: Novartis: Consultancy; Actinium Pharmaceuticals: Research Funding. Lipton: Bristol Myers Squibb, Ariad, Pfizer, Novartis: Consultancy, Research Funding. Mattsson: MattssonAB medical: Current Employment, Current holder of individual stocks in a privately-held company. Kim: Novartis: Consultancy, Honoraria, Research Funding; Paladin: Consultancy, Honoraria, Research Funding; Bristol-Meier Squibb: Research Funding; Pfizer: Honoraria.

Nanatinostat (Nstat) and Valganciclovir (VGCV) in Relapsed/Refractory (R/R) Epstein-Barr Virus-Positive (EBV +) Lymphomas: Final Results from the Phase 1b/2 VT3996-201 Study

Nanatinostat (Nstat) and Valganciclovir (VGCV) in Relapsed/Refractory (R/R) Epstein-Barr Virus-Positive (EBV +) Lymphomas: Final Results from the Phase 1b/2 VT3996-201 Study

Long-Term Survival Benefit of Eculizumab Treatment in Patients with Paroxysmal Nocturnal Hemoglobinuria: Data from the International PNH Registry

Long-Term Survival Benefit of Eculizumab Treatment in Patients with Paroxysmal Nocturnal Hemoglobinuria: Data from the International PNH Registry

Retrospective Comparison between 12-Gray and 8-Gray Total Body Irradiation (TBI) before Allogeneic Hematopoietic Cell Transplantation in Patients with Acute Lymphoblastic Leukemia in First Complete Remission

Retrospective Comparison between 12-Gray and 8-Gray Total Body Irradiation (TBI) before Allogeneic Hematopoietic Cell Transplantation in Patients with Acute Lymphoblastic Leukemia in First Complete Remission

Single Centre, Retrospective Analysis of Extracorporeal Photopheresis (ECP) Therapy in the Patients Who Are Heavily Pre-Treated for Steroid Resistant Chronic Graft-Versus-Host Disease (GVHD)

*DB and DK contributed to the work equally.BackgroundExtracorporeal photopheresis (ECP) is a recommended second or later line of therapy for chronic GVHD (cGVHD), and is beneficial not only because of increased response but also for its lack of adverse effects, specifically systemic immune suppression, mainly from steroids. In this single centre study, we attempted to evaluate not only therapeutic efficacy of ECP, but also its steroid-sparing effect by regularly analyzing steroid dose per body weight. We also attempted to identify any predictors of response or survival after ECP, which was not well defined before.Patients and methodsA total of 75 cGVHD patients (pts) who received ECP for cGVHD from 2007 to 2021 at Princess Margaret Cancer Centre were included and evaluated retrospectively. Patients and disease characteristics are as follows: median age 48.5 years (range 17-70); male 42/75 (56%); organ involvement at the time of ECP: skin (93%), oral (53%), eye (51%), gastrointestinal (25%), liver (49%), lung (57%), and musculoskeletal (n=50, 67%). Sixty-eight (91%) and 7 pts (9%) had severe and moderate grade cGVHD, respectively. Sixty-eight pts (91%) received ECP as 4 th line or beyond. They were heavily pretreated with prednisone (98%), cyclosporine (57%), tacrolimus (24%), mycophenolate mofetil (64%), azathioprine (65%), rituximab (7%), imatinib (8%), ibrunitib (3%) and ruxolitinib (1%).ECP was started twice weekly for the first 12 weeks, then twice every 2 weeks in 2012-2021, while the schedule was twice every 2 weeks from 2007-2012. If there was no response or clinical benefit noted in first 24 treatments, then ECP was discontinued. In general, we attempted to provide up to around 60 sessions based on the clinicians' discretion.The overall response rate (ORR) and clinical benefit (CB) were assessed at months 3, 6 and 12 after staring ECP. As part of standard clinical practice, NIH consensus criteria were used for grading and response assessment. CB was assessed considering clinical response as well as steroid dose reduction. Treatment failure was defined as 1) resistance to ECP requiring treatment switch, 2) non-relapse mortality (NRM), 3) relapse, 4) intolerance to ECP. Failure free survival (FFS) and overall survival (OS)were calculated from the day of ECP initiation until the endpoints of failure or death, respectively.ResultsECP was started a median of 28 months (range 1-125) after development of cGVHD. ECP was performed a median of 35 times (range 6-174) with a median duration of 11 months (range 1-53). Out of 75 pts, 48 completed planned ECP successfully and 27 stopped due to no response or benefit including, of whom 14 required additional therapy, 1 stopped due to line infection, and 1 stopped due to relapse of AML.With a median 72 months of follow-up, ORR was attained in 21% (16/75), 57% (36/63) and 70% (32/46) at month 3, 6 and 12, respectively. At 6 months, ORR was observed in 47-64% across all organs assessed. No difference in ORR was noted according to the cGVHD grade; at 6 months, severe cGVHD showed similar ORR (57%) to those with moderate cGVHD (60%) (p=0.893). CB was noted in 23% (17/75), 62% (39/63), and 76% (35/46) at month 3, 6 and 12, respectively.A total of 27/75 failures (36%) and 20/75 death (27%) occurred, due to the following: ECP resistance requiring switch to other therapy (n=14, 19%), NRM (n=11, 15%), relapse of primary disease (n=1, 1%) or ECP-related complication (n=1, 1%, line infection). In the overall cohort, FFS and OS at 12 months were 68.3% and 85.9%, respectively (Figure 1).More than a half of pts stopped steroids completely within 12 months after starting ECP. The proportion of pts off steroids was 16%, 17%, 32%, and 64% at month 0, 3, 6 and 12 after starting ECP, respectively (Figure 2).Risk factor analysis did not show any predictive markers for ORR at 6 months, while prognostic factor analysis suggested the development of musculoskeletal involvement as favorable prognostic factor for FFS (p=0.003, HR 0.315 [0.147, 0.673]) even with multivariate analysis.ConclusionOur study showed that: 1) ECP is a very effective treatment for heavily pre-treated cGVHD pts who have failed other therapies; 2) More than a half of pts can stop steroids completely within 12 months after starting ECP, thus avoiding long-term toxicity risk. Further study is warranted comparing ECP with other cGVHD treatment modalities. [Display omitted] DisclosuresPatriquin: BioCryst Pharmaceuticals: Honoraria; Alexion: Consultancy, Honoraria, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Apellis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria. Law: Novartis: Consultancy; Actinium Pharmaceuticals: Research Funding. Lipton: Bristol Myers Squibb, Ariad, Pfizer, Novartis: Consultancy, Research Funding. Mattsson: MattssonAB medical: Current Employment, Current holder of individual stocks in a privately-held company. Kim: Paladin: Consultancy, Honoraria, Research Funding; Bristol-Meier Squibb: Research Funding; Pfizer: Honoraria; Novartis: Consultancy, Honoraria, Research Funding.

Significance of Degree of HLA Disparity When Using Haploidentical Donors with T-Replete PBSC and Post-Transplantation Cyclophosphamide (PTCy) in Acute Myeloid Leukemia (AML) in First Complete Hematologic Remission (CR1)

Background: Haploidentical allogeneic hematopoietic cell transplantation (haplo) has expanded applicability of the procedure to patients for whom a suitable HLA compatible donor was not available in the past. A small multicenter retrospective study of 185 patients with hematologic malignancies who received a nonmyeloablative preparative regimen followed by infusion of bone marrow (BM) hematopoietic cells from haploidentical donors showed no significant association between the number of HLA mismatches (HLA-A, -B, -C, and -DRB1 combined) and risk of acute grade 2-4 graft-versus-host disease (GVHD) (hazard ratio [HR]=0.89; P=0.68 for 3-4 mismatches vs fewer antigen mismatches). This haploidentical transplant platform has certainly evolved. Nowadays, G-CSF mobilized peripheral blood stem cells (PBSC) are commonly used owing to its increased convenience vis-à-vis performing a BM harvest.Study population: Here, we evaluate post transplant outcomes when using haploidentical donors with T-replete PBSC and PTCy in AML in CR1. A total of 494 patients (4/8 HLA mismatch (group 1)=360, 2-3/8 HLA mismatch (group 2)=134) underwent the procedure at an EBMT participating center. The primary endpoints were cumulative incidences of grade 2-4 acute GVHD and chronic (all grades) GVHD. Secondary endpoints included cumulative incidence of relapse (RI), non-relapse mortality (NRM), leukemia-free (LFS) and overall survival (OS) and GVHD-free relapse-free survival (GRFS).Results: Group 1 and group 2 were not statistically different in regards to median age at allografting (54.1 vs. 56.1 years, p=0.51), median year of haplo transplantation (2018 vs. 2018, p=0.36), incidence of de novo AML (86.4% vs. 88.1%, p=0.63), Karnofsky equal or more than 90 (77.5% vs. 79.1%, p=0.70), and use of myeloablative conditioning (MAC) (44.7% vs. 48.5%, p=0.45). Patients in group 1 had a longer time from diagnosis to haplo-transplantation (5.3 vs. 4.9 months, p=0.03). In multivariate analysis, group 1 and group 2 did not differ in cumulative incidence of grade 2-4 acute GVHD (Hazard ratio (HR)=0.89 (95%CI=0.62-1.26), p=0.51) but group 1 had a significantly higher incidence of chronic (all grades) GVHD (HR=1.49 (95%CI=1.02-2.16), p=0.04). There was no difference in RI (HR=0.73 (95%CI=0.47-1.14), p=0.17), NRM (HR=1.25 (95%CI=0.78-2.02), p=0.36), LFS (HR=0.95 (95%CI=0.69-1.31), p=0.76), OS (HR=1.09 (95%CI=0.76-1.55), p=0.64) and GRFS (HR=1.07 (95%CI=0.81-1.42), p=0.64) between the groups. Presence of adverse cytogenetics was independently associated with higher RI (HR=1.90 (95%CI=1.20-2.99), p=0.006), inferior LFS (HR=1.59 (95%CI=1.15-2.19), p=0.005), inferior OS (HR=1.48 (95%CI=1.05-2.08), p=0.03), and worse GRFS (HR=1.54 (95%CI=1.17-2.04), p=0.002).Conclusion: Results show that patients undergoing haplo-transplantation with 4/8 (vs. 2-3/8) HLA mismatches have a higher incidence of chronic GVHD (all grades) without adversely affecting acute grade 2-4 GVHD, RI, LFS, OS and GRFS. DisclosuresLabopin: Jazz Pharmaceuticals: Honoraria. Bazarbachi: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Hikma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees. Blaise: Jazz Pharmaceuticals: Honoraria. McDonald: BioCryst Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees. Forcade: Novartis: Other: travel grant. Ciceri: IRCCS Ospedale San Raffaele: Current Employment. Mohty: Takeda: Honoraria; Astellas: Honoraria; Adaptive Biotechnologies: Honoraria; Novartis: Honoraria; Celgene: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria; Sanofi: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Gilead: Honoraria; Jazz: Honoraria, Research Funding; Pfizer: Honoraria; Amgen: Honoraria.

Efficacy and Safety of Eltrombopag Combined with Cyclosporine As First-Line Therapy in Adults with Severe Acquired Aplastic Anemia: Results of the Interventional Phase 2 Single-Arm Soar Study

Efficacy and Safety of Eltrombopag Combined with Cyclosporine As First-Line Therapy in Adults with Severe Acquired Aplastic Anemia: Results of the Interventional Phase 2 Single-Arm Soar Study

Berotralstat (BCX7353): Structure-Guided Design of a Potent, Selective, and Oral Plasma Kallikrein Inhibitor to Prevent Attacks of Hereditary Angioedema (HAE).

Hereditary angioedema (HAE) is a rare and potentially life-threatening disease that affects an estimated 1 in 50 000 individuals worldwide. Until recently, prophylactic HAE treatment options were limited to injectables, a burdensome administration route that has driven the need for an oral treatment. A substantial body of evidence has shown that potent and selective plasma kallikrein inhibitors that block the generation of bradykinin represent a promising approach for the treatment of HAE. Berotralstat (BCX7353, discovered by BioCryst Pharmaceuticals using a structure-guided drug design strategy) is a synthetic plasma kallikrein inhibitor that is potent and highly selective over other structurally related serine proteases. This once-daily, small-molecule drug is the first orally bioavailable prophylactic treatment for HAE attacks, having successfully completed a Phase III clinical trial (meeting its primary end point) and recently receiving the U.S. Food and Drug Administration's approval for the prophylactic treatment of HAE attacks in patients 12 years and older.

Berotralstat: First Approval.

Berotralstat (ORLADEYO™) is an orally administered kallikrein inhibitor, which has been developed by BioCryst Pharmaceuticals for hereditary angioedema (HAE). The inhibition of kallikrein by berotralstat decreases the production of bradykinin, which prevents the localised tissue oedema that occurs during attacks of HAE. Berotralstat has been approved in the USA, and subsequently in Japan, for prophylaxis to prevent attacks of HAE in adults and paediatric patients aged 12years or older. This article summarises the milestones in the development of berotralstat leading to this first approval for prophylaxis to prevent attacks of HAE.

Preclinical Characterization of BCX9930, a Potent Oral Complement Factor D Inhibitor, Targeting Alternative Pathway-Mediated Diseases Including Paroxysmal Nocturnal Hemoglobinuria (PNH)

INTRODUCTION: Complement factor D is a serine protease that specifically catalyzes the cleavage of factor B [bound to C3(H2O) or C3b], its only natural substrate, to Ba and Bb. Factor D has the lowest concentration in plasma among all the complement proteins and is the rate-limiting enzyme of the alternative pathway (AP) of complement. Factor D plays a key role in both AP-initiated C3 convertase formation and the amplification loop of the complement cascade. Therefore, targeting factor D is a promising therapeutic strategy to inhibit AP activation for treatment of AP-mediated diseases such as PNH, atypical hemolytic uremic syndrome, and C3 glomerulopathy. Inhibition of terminal complement C5 by eculizumab or ravulizumab results in sustained inhibition of intravascular hemolysis in patients with PNH by blocking formation of the membrane attack complex (C5b-9). However, many PNH patients treated with eculizumab continue to have symptomatic anemia, with up to half of the patients requiring blood transfusions due to extravascular hemolysis as a result of ongoing AP activation and C3 opsonization on erythrocytes. BioCryst Pharmaceuticals has developed a small-molecule, orally bioavailable human factor D inhibitor that is currently under evaluation as oral monotherapy for the treatment of patients with PNH in a Phase 1 study (BCX9930-101; NCT04330534). Here we demonstrate that BCX9930 is a potent and highly selective factor D inhibitor, and completely blocked AP activation on PNH erythrocytes in vitro. METHODS: Factor D enzymatic activity was analyzed in vitro in an esterolytic assay with a synthetic substrate and in a proteolytic assay using its natural substrate factor B bound to C3b. The selectivity was assessed in substrate-specific assays using other human serine proteases. The inhibition of AP-mediated hemolysis was assessed in vitro with rabbit erythrocytes incubated with 10% normal human serum (NHS). The Ham test was used to evaluate the inhibition by BCX9930 of AP-mediated hemolysis of erythrocytes from PNH patients with 20% acidified NHS. Inhibition of AP-mediated C3 fragment deposition was evaluated by flow cytometry using PNH erythrocytes incubated with acidified C5-depleted NHS. Activity of the classical pathway (CP) of complement l was evaluated by measuring 50% Hemolytic Complement (CH50) activity of serum and by assay of CP-mediated hemolysis of antibody-sensitized sheep erythrocytes. Pharmacodynamic effects in rhesus monkeys dosed orally with BCX9930 (100 and 200 mg twice-a-day) were assessed ex vivo with the AP Wieslab assay for the determination of C5b-9 generation after AP activation. RESULTS: BCX9930 potently inhibited esterolytic activity of purified human factor D with a mean 50% inhibitory concentration (IC50) of 14.3 nM. BCX9930 also inhibited its proteolytic activity against factor B bound to C3b with a mean IC50 of 28.1 nM. BCX9930 inhibited AP-mediated hemolysis of rabbit erythrocytes with a mean IC50 of 29.5 nM. Using the Ham test with erythrocytes from three PNH patients, BCX9930 completely suppressed AP-mediated hemolysis with a mean IC50 of 35.4 nM. Furthermore, BCX9930 suppressed C3 fragment deposition on PNH erythrocytes with a mean IC50 value of 39.3nM. BCX9930 did not inhibit enzyme activity of the human serine proteases thrombin, activated protein C, tissue plasminogen activator and trypsin up to 28 μM, and activated factor X and activated factor XII up to 50 μM. The mean IC50 values of BCX9930 inhibition of C1s and plasmin were 936 and 2850 nM, respectively. BCX9930 at a concentration up to 3 μM had no effect on CP activity in in vitro assays. Oral dosing of BCX9930 in monkeys completely suppressed AP activity of serum measured by AP-dependent generation of C5b-9. CONCLUSIONS: BCX9930 inhibitory activity on Factor D in vitro was potent and highly specific. BCX9930 completely blocked hemolysis of PNH cells in vitro and suppressed the accumulation of C3 fragments on PNH erythrocytes, indicating that BCX9930 has the potential to inhibit both intravascular and extravascular hemolysis. After oral dosing of BCX9930 in rhesus monkeys, AP activity was completely suppressed in ex vivo assays. These data demonstrate that BCX9930, an orally administered investigational drug, is a potent and selective factor D inhibitor, and that targeting factor D with BCX9930 has potential for the treatment of patients with PNH and other alternative pathway mediated diseases. Disclosures Chen: BioCryst Pharmaceuticals, Inc.: Current Employment. Cheng:BioCryst Pharmaceuticals, Inc.: Current Employment. Liu:BioCryst Pharmaceuticals, Inc.: Current Employment. Muppa:BioCryst Pharmaceuticals, Inc.: Current Employment. Parker:BioCryst Pharmaceuticals, Inc.: Current Employment. Zhu:BioCryst Pharmaceuticals, Inc.: Current Employment. Raman:BioCryst Pharmaceuticals, Inc.: Current Employment. Kotian:BioCryst Pharmaceuticals, Inc.: Current Employment. Babu:BioCryst Pharmaceuticals, Inc.: Current Employment.

BCX9930, an Oral Factor D Inhibitor, for the Potential Treatment of Alternative Pathway Mediated Diseases: Interim Results of a Phase 1 Study in Healthy Subjects

INTRODUCTION: Complement factor D is the rate-limiting enzyme for activation of the complement alternative pathway (AP). Targeting factor D is therefore an attractive therapeutic strategy for treatment of AP-mediated diseases including paroxysmal nocturnal hemoglobinuria (PNH), C3 glomerulopathy, and atypical hemolytic uremic syndrome. BCX9930 is a potent and selective orally bioavailable inhibitor of factor D in development for the treatment of PNH and other complement-mediated diseases. PNH is an acquired, chronic, non-malignant disorder of hematopoietic stem cells that is characterized by clonal deficiency of AP regulatory proteins CD55 and CD59, resulting in dysregulated AP amplification, opsonization, membrane attack complex (MAC) formation, and hemolysis. The approved intravenously (IV) administered C5 inhibitors eculizumab and ravulizumab inhibit MAC formation and intravascular hemolysis, but do not inhibit opsonization, leading to extravascular hemolysis and potentially incomplete treatment response. Inhibition of factor D is expected to prevent both intravascular and extravascular hemolysis in PNH, a distinct advantage over currently available parenteral therapies. METHODS: This abstract describes preliminary data in healthy subjects enrolled in the single ascending dose (SAD) and multiple ascending dose (MAD) evaluations of Study BCX9930-101 (NCT04330534), an ongoing first in human (FIH) study that includes randomized, double-blind, placebo-controlled evaluations of the safety and tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of BCX9930 in healthy subjects. Safety and tolerability are evaluated via clinical and laboratory monitoring. Plasma concentrations of BCX9930 are measured using a validated liquid chromatography-dual mass spectrometry (LC/MS/MS) assay; PD effects are assessed using multiple assays, including inhibition of AP activity in the AP-specific Wieslab (AP-W) and AP Hemolysis ([AP-H], lysis of rabbit red blood cells [RBCs] by human serum) assays. RESULTS: To date, 48 subjects have been enrolled into 6 SAD cohorts (n = 6 BCX9930, n = 2 placebo per cohort), with doses ranging from 10 to 1200 mg. Sixty subjects have been enrolled into 5 MAD cohorts (n = 10 BCX9930, n = 2 placebo per cohort), with doses ranging from 50 mg every 12 hours (Q12h) to 400 mg Q12h. The mean age of all enrolled subjects was 34.3 years and 50.9% were male. BCX9930 was safe and generally well-tolerated at all doses evaluated. There were no serious adverse events or dose-related safety signals. Mild headache was the most frequent treatment-emergent adverse event and showed no correlation with dose. A benign maculopapular exanthem attributed to study drug was observed following MAD administration. These events were mild or moderate in severity and resolved in a median of 5 days. BCX9930 exposure was approximately linear and dose-proportional across all evaluated SAD and MAD doses. Mean BCX9930 concentrations at 12 hours post dose were ≥ 8 to 10 times the factor D half-maximal effective concentration (EC50) for SAD doses ≥ 300 mg and for MAD doses ≥ 100 mg Q12h at steady-state. Rapid, dose-dependent AP suppression was observed following SAD and MAD, as measured by the AP-W and AP-H assays (Figure 1). AP suppression &amp;gt; 98% was observed in both assays at steady state for MAD doses ≥ 200 mg Q12h. Duration of complete suppression increased with dose and was ≥ 12 hours for MAD doses ≥ 200 mg Q12h. Doses ≥ 200 mg Q12h showed greater, more durable, and more consistent inhibition across subjects compared with doses ≤ 100 mg Q12h. PK/PD modeling of AP-H and AP-W demonstrates a clear concentration-response, with estimated EC50 values between 21.7 and 40.7 nM. These estimates are consistent with the in vitro IC50 for inhibition of proteolytic activity against the natural substrate C3bB of 28.1 nM. CONCLUSIONS: BCX9930 is a potent and selective orally bioavailable inhibitor of human complement factor D. In this preliminary analysis of an ongoing FIH study, BCX9930 displayed a promising safety and tolerability profile. Exposure was approximately linear and dose-proportional across a wide dose range, and complete and durable suppression of the AP was achieved. Together, these findings support further evaluation of BCX9930 in patients with PNH and other AP-mediated diseases. Disclosures Davidson: BioCryst Pharmaceuticals, Inc.:Current Employment.Mathis:BioCryst Pharmaceuticals, Inc.:Current Employment.Mair:Quotient Sciences:Current Employment.Gesty-Palmer:BioCryst Pharmaceuticals, Inc.:Current equity holder in publicly-traded company, Ended employment in the past 24 months.Cornpropst:BioCryst Pharmaceuticals, Inc.:Current Employment.Sheridan:BioCryst Pharmaceuticals, Inc.:Current Employment.Chen:BioCryst Pharmaceuticals, Inc.:Current Employment.Reynolds:BioCryst Pharmaceuticals, Inc.:Current Employment.Parker:BioCryst Pharmaceuticals, Inc.:Current Employment.Babu:BioCryst Pharmaceuticals, Inc.:Current Employment.

Oral Plasma Kallikrein Inhibitor BCX7353 for Treatment of Hereditary Angioedema

Hereditary angioedema (HAE) is rare disorder caused by a SERPING1 gene mutation that triggers severe swelling of the skin and upper airway. Treatment options for HAE with deficient and dysfunctional C1-inhibitor are expanding to include small-molecule drugs that inhibit protein interactions in the kallikrein-kinin system. Discovered by BioCryst Pharmaceuticals, BCX7353 is a synthetic, once-daily, small molecule drug that can be taken as an oral capsule to treat HAE attacks and for prophylaxis. This article will summarize recent and current BCX7353 clinical trials. Overall, results indicate BCX7353 is a promising form of therapy with a rapid 1 h onset of action, long duration of action, and acceptable tolerance.

Oral Plasma Kallikrein Inhibitor for Prophylaxis in Hereditary Angioedema

BackgroundHereditary angioedema is a life-threatening illness caused by mutations in the gene encoding C1 inhibitor (also called C1 esterase inhibitor) that lead to overactivation of the kallikrein–bradykinin cascade. BCX7353 is a potent oral small-molecule inhibitor of plasma kallikrein with a pharmacokinetic and pharmacodynamic profile that may help prevent angioedema attacks.MethodsIn this international, three-part, dose-ranging, placebo-controlled trial, we evaluated four doses of BCX7353 (62.5 mg, 125 mg, 250 mg, and 350 mg once daily) for the prevention of angioedema attacks over a 28-day period. Patients with type I or II hereditary angioedema with a history of at least two angioedema attacks per month were randomly assigned to BCX7353 or placebo. The primary efficacy end point was the number of confirmed angioedema attacks. Key secondary end points included angioedema attacks according to anatomical location and quality of life.ResultsA total of 77 patients underwent randomization, 75 received BCX7353 or placebo, and 72 completed the trial. The rate of confirmed angioedema attacks was significantly lower among patients who received BCX7353 at daily doses of 125 mg or more than among those who received placebo, with a 73.8% difference at 125 mg (P<0.001). Significant benefits with respect to quality-of-life scores were observed in the 125-mg and 250-mg dose groups (P<0.05). Gastrointestinal adverse events, predominantly of grade 1, were the most commonly reported adverse events, particularly in the two highest BCX7353 dose groups.ConclusionsOnce-daily oral administration of BCX7353 at a dose of 125 mg or more resulted in a significantly lower rate of attacks of hereditary angioedema than placebo. Mild gastrointestinal symptoms were the principal side effect. (Funded by BioCryst Pharmaceuticals; APeX-1 ClinicalTrials.gov number, NCT02870972.)

Efficacy of Galidesivir against Ebola Virus Disease in Rhesus Monkeys

BackgroundThe recent re-emergence of Ebola virus in the Democratic Republic of the Congo serves as a stark reminder of the 2013–2016 Ebola virus (EBOV), which resulted in >11,000 deaths. To date, there are no approved therapeutics or vaccines for EBOV disease (EVD). Galidesivir (BCX4430) is an adenosine nucleoside analogue designed to inhibit viral RNA polymerase activity indirectly through non-obligate RNA chain termination. Galidesivir exhibits in vitro antiviral activity against a broad spectrum of negative- and positive-sense RNA viruses. In vivo, galidesivir has shown antiviral activity against various viruses and provides 100% protection against Marburg virus disease in cynomolgus macaques, when administered either 1 or 2 days post infection. Initial exploratory studies in a rhesus macaque model of EVD showed that 25 mg/kg galidesivir administered twice daily (BID) IM beginning immediately following viral challenge protected 100% (6 of 6) of animals.MethodsPharmacokinetic modeling based on galidesivir levels in healthy and EBOV-infected animals predicted that a loading-dose regimen could decrease time to steady-state, potentially advantageous when extending the time of treatment initiation. To test the efficacy of a loading dose regimen, 100 mg/kg was administered BID either 2 or 3 days after challenge, followed by maintenance doses of 25 mg/kg BID for a total duration of 11 days.ResultsSix of 6 (100%) rhesus monkeys survived after receiving loading doses on day 2, and 4 of 6 (67%) animals survived after receiving loading doses beginning day 3. In the dosing regimen that conferred 100% protection, the animals exhibited either no behavioral depression or only mild and transient behavioral depression. In all treated groups, there was a significant reduction of plasma viral RNA concentrations during the acute phase of disease.ConclusionGalidesivir protects rhesus monkeys against an otherwise lethal EBOV challenge. Administered by IM injection, Phase 1 human clinical studies of single and multiple ascending doses have shown galidesivir to be generally safe and well tolerated up to 10 mg/kg daily for seven days. Additional clinical studies are planned to evaluate the safety and tolerability of galidesivir administered by IV infusion. Supported by NIAID (NIH), HHSN272201300017C.Disclosures S. MacLennan, BioCryst: Employee, Salary. A. Mathis, BioCryst Pharmaceuticals: Employee, Salary. E. Giuliano, BioCryst: Employee, Salary. R. Taylor, BioCryst Pharmaceuticals: Employee, Salary. W. Sheridan, BioCryst Pharmaceuticals: Employee, Salary.