ALBERT

Description: Dysregulation of the alternative complement pathway (AP) predisposes individuals to a number of diseases including paroxysmal nocturnal hemoglobinuria, atypical hemolytic uremic syndrome, and C3 glomerulopathy. Moreover, glomerular Ig deposits can lead to complement-driven nephropathies. Here we describe the discovery of a highly potent, reversible, and selective small-molecule inhibitor of factor B, a serine protease that drives the central amplification loop of the AP. Oral administration of the inhibitor prevents KRN-induced arthritis in mice and is effective upon prophylactic and therapeutic dosing in an experimental model of membranous nephropathy in rats. In addition, inhibition of factor B prevents complement activation in sera from C3 glomerulopathy patients and the hemolysis of human PNH erythrocytes. These data demonstrate the potential therapeutic value of using a factor B inhibitor for systemic treatment of complement-mediated diseases and provide a basis for its clinical development.

Description: Background/Objective: Breakthrough hemolysis (BTH) is the return of hemolytic disease activity during treatment with complement C5 inhibitors for paroxysmal nocturnal hemoglobinuria (PNH). BTH may be associated with inadequate C5 inhibition or complement activating conditions (eg, infection). Despite reports that up to 19% of patients (pts) receiving eculizumab may experience BTH, there is no commonly accepted definition of BTH. The definition of BTH was derived from literature review and expert consensus. BTH was defined as ≥1 new or worsening symptom/sign of intravascular hemolysis (fatigue, hemoglobinuria, abdominal pain, dyspnea, anemia [hemoglobin

Description: Introduction Ravulizumab, an innovative complement C5 inhibitor given every 8 weeks (q8w), was recently demonstrated in a large phase 3 study of patients (pts) with paroxysmal nocturnal hemoglobinuria (PNH) and naïve to complement inhibitor therapy to be non-inferior to eculizumab given every 2 weeks (q2w) across all endpoints that measured different aspects of PNH disease (transfusion avoidance [TA], lactate dehydrogenase normalization [LDH-N], percent LDH reduction, breakthrough hemolysis [BTH], Functional Assessment of Chronic Illness Therapy [FACIT]-Fatigue, and hemoglobin stabilization [HGB-S]) (Lee JW et al. EHA Learning Center, Jun 17, 2018; LB2603). PNH pts currently receiving eculizumab may experience treatment burden associated with the q2w dosing regimen. With the development of ravulizumab, PNH pts on prior eculizumab therapy can potentially switch to ravulizumab without interruption of treatment. The primary objective of this study was to assess the noninferiority of ravulizumab compared to eculizumab in adult PNH pts who were clinically stable after having been treated with eculizumab for at least 6 months. Methods In this phase 3, open-label, multicenter study (NCT03056040), adult pts with a documented diagnosis of PNH who were treated with labelled-dose eculizumab for 〉6 months having LDH levels ≤1.5 times the upper limit of normal at screening were randomly assigned 1:1 to continue eculizumab or switch to ravulizumab. Pts randomized to ravulizumab received weight-based loading [day 1]/maintenance doses [day 15 and q8w thereafter]: ≥40 to

Description: Life-threatening thromboembolism (TE) is the most feared complication in patients with paroxysmal nocturnal hemoglobinuria (PNH). Thrombophilia in PNH likely involves a hypercoagulable state, possibly due to intravascular hemolysis with scavenging of the coagulation regulator nitric oxide, and platelet activation. Approximately 45% of PNH deaths result from TE. Thrombosis is more frequent in patients with larger PNH clones, but can occur in patients with smaller clones. Primary prophylactic anti-coagulation may reduce the thrombotic risk in PNH patients, although controlled studies have not been performed and there is a known serious hemorrhage risk. A randomized, placebo-controlled, 26-week phase 3 study of the terminal complement inhibitor eculizumab in 87 PNH patients (TRIUMPH) recently demonstrated dramatic reductions in intravascular hemolysis and RBC transfusions; 1 TE was reported with placebo and 0 with eculizumab. This single study was not powered to examine the effect of eculizumab on TE, and we prospectively examined the aggregate TE event rate in eculizumab-treated patients from TRIUMPH, the two other PNH trials, and the subsequent phase 3 extension study as compared to each patient’s pre-treatment event rate. Before receiving eculizumab, examination of patient records identified 126 TE events in 195 patients, and 103 were on anticoagulants. While pre-treatment TE event rates were variable in the 3 individual PNH studies, eculizumab reduced TE in each study. The TE event rate with eculizumab treatment was 1.22 per 100 patient years, compared to 7.49 (p

Description: To selectively modulate human complement alternative pathway (CAP) activity implicated in a wide range of acute and chronic inflammatory conditions and to provide local cell surface and tissue-based inhibition of complement-induced damage, we developed TT30, a novel therapeutic fusion protein linking the human complement receptor type 2 (CR2/CD21) C3 fragment (C3frag = iC3b, C3dg, C3d)-binding domain with the CAP inhibitory domain of human factor H (fH). TT30 efficiently blocks ex vivo CAP-dependent C3frag accumulation on activated surfaces, membrane attack complex (MAC) formation and hemolysis of RBCs in a CR2-dependent manner, and with a ∼ 150-fold potency gain over fH, without interference of C3 activation or MAC formation through the classic and lectin pathways. TT30 protects RBCs from hemolysis and remains bound and detectable for at least 24 hours. TT30 selectively inhibits CAP in cynomolgus monkeys and is bioavailable after subcutaneous injection. Using a unique combination of targeting and effector domains, TT30 controls cell surface CAP activation and has substantial potential utility for the treatment of human CAP-mediated diseases.

Description: Clinical and laboratory evidence support an immune pathogenesis in most cases of idiopathic aplastic anemia (AA) and closely related disorders such as paroxysmal nocturnal hemoglobinuria (PNH). While external triggers are likely necessary, a complex constellation of immunogenetic factors may determine disease susceptibility. Many immunogenetic factors can influence the quality of immune response and affect the propensity to immune-mediated attack on hematopoietic stem cells in AA. Here we investigated whether KIR and KIR-L (HLA-A) genotype and cytokine/receptor gene variants are over-represented in AA and PNH. We studied a cohort of 77 patients with AA (23 AA, 20 AA/PNH and 34 PNH), 10 with hypocellular MDS and 175 healthy controls. The following SNPs in immunoregulatory genes were analyzed: IL-1α (−889 T/C), IL-2 (−330 T/G +166 G/T), IL-4 (−1098 T/G −590 T/C −33 T/C), IL-1R (−1970 C/T), IL-1Rα (mspa111100 T/C), IL-4RA (+ 190 G/A), IL-1β (−511 C/T, +3962 T/C), IL-6 (−174 C/G, nt565 G/A), IL-10 (−1082 G/A, −819 C/T, −592 C/A), IL-12 (−1188 C/A), TGF-β (+10 C/T, +25 G/C), INF-γ (+874 A/T), TNF-α (−308 G/A, −238 G/A) and immunomodulatory receptor genes including CTLA-4 exon 6 (+49 G/A), FcRIIIa (158 F/V) and CD45-exons 6 (+138 A/G), and 4 (+54 A/G, +77 C/G). As binding of KIR to the appropriate HLA ligand (KIR-L) can modulate activation of NK and cytotoxic T cells, we examined the combined impact of KIR/KIR-L genotypes on the risk of AA and PNH syndrome. In AA we found a decreased frequency of inhibitory KIR-2DL3 genes (68% vs. 89%, p=.0002); analysis of the KIR genotype in correlation with the corresponding KIR-L profile, revealed a decreased frequency of stimulatory 2DS1/C2 mismatch resulting in a potentially enhanced cytotoxic activity (14% vs.44%, p=.003). No association was found for most of the SNPs tested. However, when we examined the frequency TGF-β genotypes, increased frequency of GG variant in codon 25 (61% vs. 35% in controls, p=.03), associated with the “high secretor” phenotype, was found in AA. This relationship was also present in hypocellular MDS (82% vs. 32%, p=.007). Additionally, we found a lower incidence of TT genotypes for the IL-1Rα gene (33% vs. 62% p=.02). We confirm that the hypersecretor genotype T/T of INF-γ was over-represented in AA (28% vs. 10% in controls, p=.02). Subgroup analysis revealed that the T/T genotype of IFN-γ (35% vs. 14% p=.01) correlated with presence of a PNH clone. Previously, we have shown the association of HLA-DR15 with responsiveness to immunosuppression. When AA patients were subgrouped according to response to ATG/CsA, therapy refractoriness correlated with the presence of the C2/C2 haplotype (30% vs. 0% p=.02) and inhibitory KIR-2DL3/C1 mismatch (70% vs. 0%, p=.01) which may result in a greater propensity to breach of self-tolerance. In comparison, in the total AA group, C2/C2 haplotype and KIR-2DL3/C1 mismatch were present in 17% vs. 24% and 8% vs. 16% of controls, respectively. An increase in the frequency of 2DL3 and a decrease in 2DS1 mismatch may result in imbalance between cytotoxicity and KIR inhibition. In sum, our findings demonstrate that complex inherited traits involving immunogenetic factors may genetically determine propensity to bone marrow failure syndromes.

Description: Background: PNH is a rare, acquired blood disorder. A somatic mutation in the PIGA gene of one or more hematopoietic stem cells generates a clone of abnormal erythrocytes (RBCs) that lack alternative pathway (AP) regulatory complement proteins CD55 and CD59. This leads to uncontrolled complement activation on affected RBCs and intravascular hemolysis (IVH). Standard of care is C5 inhibition to prevent membrane attack complex (MAC) formation. Despite preventing MAC-mediated IVH, many patients experience extravascular hemolysis (EVH). Despite C5 inhibition, ~ 70% of patients remain anemic and 〉1/3 were transfused 〉 1 time in the prior 12 months. Factor D (FD), a serine protease, catalyzes complement factor B cleavage, allowing formation of AP C3 convertase. By inhibiting FD, oral danicopan blocks C3 convertase formation, the control point for AP activation and amplification of all pathways. This leads to inhibition of C3 cleavage, C3 fragment deposition, terminal pathway activation and MAC formation. Thus, danicopan can control both IVH and EVH therefore, making FD a promising target. Aim: Demonstrate that danicopan is a potential treatment for PNH patients with an inadequate response to C5 inhibition. Methods: Data are presented for this Ph 2, dose-finding, proof of concept trial of danicopan in patients with an inadequate response to eculizumab who were transfusion dependent. Additional criteria in Table 1. In addition to the current eculizumab regimen, danicopan starting doses were 100-150 mg TID, with dose escalation up to 200 mg TID, based on clinical and biochemical response, at protocol defined time points (Figure 1). The primary endpoint was change in Hgb at Treatment Week (TW) 24. Secondary efficacy parameters included transfusion needs, effect on lactate dehydrogenase (LDH), and an exploratory an endpoint of Functional Assessment of Chronic Illness Therapy (FACIT) FATIGUE scores. General safety, tolerability, and PK/PD of danicopan were measured. After TW 24, patients entered a long-term extension. Results: Twelve patients received at least one dose of danicopan. One patient discontinued after 2 doses, due to a serious adverse event of worsening of an underlying condition (pulmonary hypertension/edema), considered unlikely related to danicopan. This patient is excluded from this analysis. Eleven patients continue to receive treatment. Dose titrations are shown in Table 2. Benefits were observed in multiple laboratory markers of PNH, shown in Table 3. Hgb improved in all patients, with a mean Hgb gain of 2.6 g/dL at 24 Weeks of treatment (n=4). Meaningful improvement in FACIT Fatigue scores were reported, with a mean increase of 8 points relative to the baseline on eculizumab. A 3-point change is clinically meaningful on this scale. Transfusion needs dramatically reduced, with one patient receiving one transfusion during the trial, as compared to 34 transfusions (58 units) in 10 patients, in the 6 months prior to screening. One patient (who does not accept blood products due to religious objections and also has hereditary elliptocytosis) had a baseline Hgb=5 g/dL with a 3.5 g/dL improvement at TW24 and significant improvement in fatigue. C3 fragment deposition was inhibited; reticulocytes, total/ direct bilirubin and LDH returned to normal range. Baseline C5 inhibition (classical pathway activity) was essentially inhibited (mean=1 [range 60-144]). Three of 11 patients received 〉 900 mg eculizumab, making PK a less likely reason for inadequate response. Danicopan has been well tolerated; 96% of treatment emergent adverse events (TEAEs) were mild to moderate in severity and no discontinuations due to TEAEs. Two patients had Grade 3 TEAEs which resolved and continued in the trial. Conclusion: Proof of concept is established with danicopan, an oral, small molecule FD inhibitor in the treatment of PNH in combination with eculizumab. Meaningful improvements in Hgb, transfusion needs, FACIT-FATIGUE and other parameters of interest were achieved. These clinically significant improvements demonstrate that further benefit can be achieved by blocking the alternative pathway at FD with danicopan, in combination with C5 inhibition. This benefit is likely due to the prevention of C3-mediated EVH, in addition to control of IVH. Danicopan targets an unmet need in PNH and will be further evaluated in a pivotal trial in combination with standard of care C5 inhibition. Disclosures Kulasekararaj: Achillion: Consultancy; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Alexion: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Ra Pharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Akari: Honoraria, Membership on an entity's Board of Directors or advisory committees; Alnylam: Membership on an entity's Board of Directors or advisory committees. Risitano:Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amyndas: Consultancy; Achillion: Research Funding; Amyndas: Consultancy; Apellis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Samsung: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Alexion: Honoraria, Research Funding, Speakers Bureau; Alexion: Honoraria, Research Funding, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Alnylam: Research Funding; Achillion: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Ra Pharma: Research Funding; Biocryst: Membership on an entity's Board of Directors or advisory committees; Alnylam: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees; Biocryst: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Ra Pharma: Research Funding; Samsung: Membership on an entity's Board of Directors or advisory committees; Apellis: Honoraria, Membership on an entity's Board of Directors or advisory committees. Maciejewski:Novartis: Consultancy; Alexion: Consultancy. Notaro:Alexion: Membership on an entity's Board of Directors or advisory committees, Other: letture fees. Browett:Janssen: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; Beigene: Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees; Achillion: Research Funding. Lee:Alexion: Consultancy, Honoraria, Research Funding; Achillion: Research Funding. Huang:Achillion: Employment, Equity Ownership. Geffner:Achillion: Employment, Equity Ownership. Brodsky:Alexion: Membership on an entity's Board of Directors or advisory committees, Other: Grant funding; Achillion: Research Funding.

Description: Acquired marrow failure syndromes may globally affect all hematopoietic lineages, as in severe aplastic anemia (SAA), or may selectively involve single lineages, as in pure red cell aplasia (PRCA) or in agranulocytosis (AGR). All these conditions share a cellular immune-mediated pathophysiology, which is supported by many experimental data; thus, various immunosuppressive (IS) strategies have been exploited. Alemtuzumab (MabCampath®) (ALE) is a lympholytic MoAb with strong and prolonged IS activity, more reliable than ATG or ALG as for activity, dosing and commercial availability. Here we report a phase II/III pilot study with ALE followed by low-dose cyclosporine A (CsA) on 11 patients suffering from SAA (n=4), PRCA (n=5) or AGR (n=2). All patients received ALE as s.c. injection premedicated by betamethasone, clorpheniramine and paracetamol, with a dose escalating schedule of 3-10-30-30-(30) mg in consecutive days; the total dose was 103 mg for SAA, and 73 for PRCA and AGR. Six patients received one or more additional courses as a result of relapse, so a total of 18 courses were administered. All patients on day 7 started oral low dose CsA (1 mg/kg). Valgancyclovir 450 mg bi-daily and trimethoprim-sulphamethoxazole bi-daily thrice a week were administered as anti-CMV and anti-Pneumocystis Carinii prophylaxis, respectively. All patients completed the treatment, with severe or moderate infusion-related side effect (fever, chills and/or injection site reaction) occurring in 1 (not premedicated) and 3 cases, respectively. No significant abnormality of routine biochemical testing, nor other medically significant adverse events were reported. A complete lympho-ablation was observed in all patients within 2–3 days, which persisted for several weeks; in addition, transient worsening of neutropenia (managed by occasional G-CSF support) and of thrombocytopenia were observed in some patients. At a median follow-up of 6 months, infectious events were irrelevant: in cumulative 75 patient-months, 1 HSV and 1 flu have been recorded (globally 1 day of fever), all resolving quickly. No CMV reactivation was demonstrated. Immune reconstitution was delayed up to several months, with absolute lymphocyte count ranging between 30–200/uL, 100–400/uL, 250–800/uL and 500–2000/uL at months +1, +3, +6 and +12 from the treatment. The CD4+ compartment was significantly more affected than the CD8+, with a persistent inversion of the CD4/CD8 ratio. As for efficacy, the 4 SAA patients showed 1 CR, 1 PR (both relapsing at 6 months and re-treated with additional ALE courses), 1 NR at 3 months (addressed to early stem cell transplantation due to life-threatening hemorrhages); 1 is not evaluable yet. In the 5 PRCAs, there were 4 CR and 1 NR (at 3 months); 3 responding patients relapsed and were successfully managed by further courses of ALE. The 2 AGRs showed both CR, followed by late relapse (at 18 months) in one case (now receiving a second course). In conclusion, ALE administered as subcutaneous injection is a feasible and safe IS regimen for patients suffering from immune-mediated marrow failure syndromes. Infectious complications were unremarkable, and preliminary results suggest good efficacy, especially in lineage-restricted forms; as with other IS regimens, the hematological response is late (3–4 months) and relapses may occur, which are sensitive to further ALE courses. Such favorable risk-to-benefit ratio predicts for this regimen a leading position in the future IS strategies.