Akari Therapeutcis (AKTX) Announces Positive Interim Data from Phase III Paroxysmal Nocturnal Hemoglobinuria Study

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, today announces positive interim data from its Phase III PNH CAPSTONE study in complement inhibitor naïve, transfusion-dependent PNH patients. All patients treated with nomacopan achieved the primary endpoint of transfusion independence.

Dr Austin Kulasekararaj of King’s College Hospital, London University, UK, the lead investigator on the long-term CONSERVE safety and efficacy study of nomacopan in patients with PNH commented, “The study was originally designed to achieve approximately 50% transfusion independence in line with the original eculizumab Phase III PNH pivotal trials, so this initial data is very promising and in combination with the excellent results of the long-term study demonstrate the effectiveness of nomacopan as a complement inhibitor in PNH. In addition, to date nomacopan appears to be well tolerated.”

PNH is an orphan hematological condition that, if left untreated, results in a high mortality rate. Eculizumab, a C5 complement inhibitor, is approved for the treatment of the disease. Nomacopan is also a C5 complement inhibitor which also binds the proinflammatory eicosanoid leukotriene B4 (LTB4).

In the Phase III CAPSTONE trial, PNH patients, naïve to anti-complement treatment, are randomized to receive daily subcutaneous nomacopan or SOC (blood transfusion with or without anticoagulation) for six months. After six months, patients on SOC receive nomacopan for three months and patients on nomacopan continue the drug for a further three months. The trial design was agreed with the FDA following an end of Phase II meeting. The primary endpoint of this study is: haemoglobin (Hb) stabilization defined as Hb greater than the set point for each patient set during the pre-study randomization period, and the avoidance of packed red blood cell transfusions during the treatment period of 180 days. All patients receive a transfusion if they fall below the Hb set point.

The interim data tabulated below shows that the four patients on nomacopan met the primary endpoint and received no transfusions for the first six months of treatment while all four patients on placebo were transfused during the first six months of treatment. Both groups had similar historic transfusion levels and mean Hb set points. The difference is statistically significant at the p=0.034 level.

In the Phase II COBALT PNH study six out of eight patients were transfusion dependent prior to treatment. Three became transfusion independent during the three-month Phase II study and the remaining three became transfusion independent during treatment with nomacopan in the long-term follow-up safety study, where transfusion independence is defined as no transfusion for 6 months. Of these six patients all have now continually maintained transfusion independence for up to two years except one patient who has received one unit of PRBC in the last 12 months.

In total, 14 PNH patients have been treated with nomacopan across four trials: Phase II, Phase III, PNH eculizumab resistant study, and PNH long-term safety and efficacy study. Additional interim Phase III data is expected to be announced during the European Hematology Association Annual Congress being held June 11-14, 2020 in Frankfurt, Germany.

Akari is currently developing a new higher concentration formulation of nomacopan allowing a small volume 0.3mL, low viscosity injection, with an insulin pen-like injector holding one week’s daily dosing stable at room temperature, improving both patient comfort and convenience. Recruitment into the Phase III CAPSTONE study is currently deferred in order to potentially take advantage of this new formulation.

“This interim PNH transfusion further demonstrates the positive patient treatment benefit and tolerability of nomacopan in PNH patients,” commented Clive Richardson, CEO of Akari Therapeutics. “The positive PNH data in turn supports our lead programs in bullous pemphigoid (BP), pediatric hematopoietic stem cell transplant-related thrombotic microangiopathy (HSCT-TMA) and atopic keratoconjunctivitis (AKC), where C5 and LTB4 may both play a role in disease pathology.”

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