Akari Therapeutics Announces Pivotal Phase III Trial Design of Nomacopan in Pediatric Hematopoietic Stem Cell Transplant-Related Thrombotic Microangiopathy (HSCT-TMA), Following FDA Meeting

Update on Paroxysmal Nocturnal Hemoglobinuria (PNH) Long Term Safety Study Shows 100% Transfusion Independence

• Two-part pivotal Phase III study of nomacopan in pediatric patients with HSCT-TMA based on guidance from End-of-Phase II meeting with U.S. Food and Drug Administration (FDA):

‒        Part A dose confirmation study. Dosing scheme has been agreed with the FDA through Akari’s participation in the Model Informed Drug Development (MIDD) Program.

‒        Part B single arm responder-based efficacy study will follow an interim analysis of Part A and a meeting with the FDA.

• Phase III HSCT-TMA study expected to open by the end of Q4 2019.
• HSCT-TMA program has received both orphan and Fast Track designations from the FDA.
• New data from ongoing long-term PNH study shows that all six patients from the Phase II study who were transfusion dependent at entry are now transfusion independent on nomacopan.

NEW YORK and LONDON, December 2, 2019 – Akari Therapeutics, Plc (Nasdaq: AKTX), a biopharmaceutical company focused on innovative therapeutics to treat orphan autoimmune and inflammatory diseases where the complement and/or leukotriene systems are implicated, announces the design of a pivotal Phase III pediatric trial in HSCT-TMA following a FDA End-of-Phase II meeting. Akari also announces that, in another hematological condition, all six patients from the long-term Phase II PNH study who were transfusion dependent at entry are now transfusion independent on long-term treatment with nomacopan.

HSCT-TMA is an orphan hematological condition with no approved treatments and an estimated mortality rate of more than 80% in children with the severe form of the disease¹. It is this severe form that is being targeted with nomacopan. Following a recent End-of-Phase II meeting with the FDA, Akari plans to initiate a single arm responder-based study design, based on treatment with nomacopan for up to 24 weeks. The primary endpoints are focused on disease response defined primarily by renal improvement and reduced transfusion dependence. The study will be in two parts, with data from seven patients in Part A used to confirm dosing and endpoints for Part B, with the pharmacokinetic (PK) modelling agreed with the FDA through Akari’s participation in the Model Informed Drug Discovery Program (MIDD). Following an interim efficacy and safety readout from Part A and meeting with the FDA, patients would then be recruited into Part B of the responder study.

While the role of complement inhibition is understood to play an important role in HSCT-TMA, LTB4 may also be an important target in reducing epithelial activation in both TMA and graft versus-host disease² (GVHD) which often occur simultaneously. Daily dosing with nomacopan is also likely to be of a particular advantage in facilitating more complete complement suppression, especially in HSCT-TMA patients with high transfusion requirements.

HSCT-TMA is Akari’s second haematological clinical program and follows a successful Phase II study in PNH completed in early 2018, after which patients continued treatment with nomacopan in a long-term safety study. New data from Akari’s ongoing long-term study, shows that all six patients from the Phase II study who were transfusion dependent at entry are now transfusion independent on nomacopan, having had in all cases no transfusions for a minimum of six months. In addition, during more than 20 cumulative patient-years of PNH patient treatment with nomacopan, there have been no reported drug-related serious adverse events.

“Following our meeting with the FDA, we look forward to starting the pivotal Phase III study of nomacopan in HSCT-TMA, a potential treatment for a high risk pediatric population which currently has no approved therapies. If successful, we expect this will be a gateway indication into a range of other poorly treated orphan TMAs,” commented Clive Richardson, CEO Akari Therapeutics. “We are pleased with the progress being made across our clinical studies where recent positive clinical data in bullous pemphigoid (BP) and PNH provides further support for the underlying efficacy of nomacopan.”

1 Sonata Jodele, et al. New approaches in the diagnosis, pathophysiology, and treatment of pediatric hematopoietic stem cell transplantation associated thrombotic microangiopathy. Transfus Apher Sci . 2016 April; 54(2): 181–190

2 Takatsuka, et al. Predicting the severity of intestinal graft-versus-host disease from leukotriene B4 levels after bone marrow transplantation. Transplantation 2000, 26: 1313-1316

About Akari Therapeutics

Akari is a biopharmaceutical company focused on developing inhibitors of acute and chronic inflammation, specifically for the treatment of rare and orphan diseases, in particular those where the complement (C5) or leukotriene (LTB4) systems, or both complement and leukotrienes together, play a primary role in disease progression. Akari's lead drug candidate, nomacopan (formerly known as Coversin), is a C5 complement inhibitor that also independently and specifically inhibits leukotriene B4 (LTB4). Nomacopan is currently being clinically evaluated in four indications: bullous pemphigoid (BP), atopic keratoconjunctivitis (AKC), thrombotic microangiopathy (TMA), and paroxysmal nocturnal hemoglobinuria (PNH). Akari believes that the dual action of nomacopan on both C5 and LTB4 may be beneficial in AKC and BP. Akari is also developing other tick derived proteins, including longer acting versions.