• Phase 3 study of antolimab for the treatment of eosinophilic gastritis and/or eosinophilic duodenitis (previously referred to as eosinophilic gastroenteritis)
  • Phase 2/3 study of antolimab for the treatment of eosinophilic esophagitis
  • Phase 1 study of subcutaneously administered antolimab in healthy volunteers

REDWOOD CITY, CA, USA I March 24, 2020 I Allakos Inc. (Nasdaq: ALLK), a biotechnology company developing antolimab (AK002) for the treatment of eosinophil and mast cell related diseases, today reported the initiation of three clinical studies of antolimab: a Phase 3 study in eosinophilic gastritis (EG) and/or eosinophilic duodenitis (EoD), a Phase 2/3 study in eosinophilic esophagitis (EoE), and a Phase 1 study of subcutaneously administered antolimab in healthy volunteers. The Phase 3 EG and/or EoD study and the Phase 2/3 EoE study follow positive results from ENIGMA, the Company’s multicenter, randomized, double-blind, placebo-controlled Phase 2 study in patients with EG and/or EoD.

Phase 3 Eosinophilic Gastritis (EG) and/or Eosinophilic Duodenitis (EoD) Study Design
The multicenter, randomized, double-blind, placebo-controlled Phase 3 trial will enroll approximately 160 patients with active, biopsy-confirmed EG (eosinophil count of ≥30 eosinophils in 5 high powered fields [hpfs] in the stomach) and/or EoD (eosinophil count of ≥30 eosinophils in 3 hpfs in duodenum). Patients will be randomized 1:1 to receive: (a) 1.0 mg/kg of antolimab for the first month followed by five doses of 3.0 mg/kg given monthly, or (b) monthly placebo. The co-primary endpoints of the study are: 1) the proportion of patients achieving ≤ 4 eosinophils in 5hpfs in the stomach and/or ≤15 eosinophils in 3hpfs in the duodenum and 2) absolute change in Total Symptom Score (TSS-6: abdominal pain, nausea, bloating, early satiety, abdominal cramping, loss of appetite) measured using the daily patient reported symptom questionnaire used in ENIGMA. The TSS-6 consists of the six most frequent and severe symptoms reported in ENIGMA.

Phase 2/3 Eosinophilic Esophagitis (EoE) Study Design
The multicenter, randomized, double-blind, placebo-controlled Phase 2/3 trial will enroll approximately 300 patients with active, biopsy-confirmed EoE (eosinophil count of ≥15 eosinophils in a single hpf). Patients will be randomized 1:1:1 to receive: (a) six antolimab doses of 1.0 mg/kg given monthly, (b) 1.0 mg/kg of antolimab for the first month followed by five doses of 3.0 mg/kg given monthly, or (c) monthly placebo. The co-primary endpoints of the study are: (1) the proportion of patients achieving ≤6 eosinophils in a single hpf and (2) absolute change in dysphagia symptoms measured using a daily patient reported symptom questionnaire known as the Dysphagia Symptom Questionnaire (DSQ).

Phase 1 Study of Subcutaneously Administered Antolimab in Healthy Volunteers
The randomized, double-blind, placebo-controlled Phase 1 trial will evaluate the safety, pharmacokinetics, and pharmacodynamics of subcutaneously administered antolimab in healthy volunteers.

Conference Call and Live Webcast
The Company will host a conference call and webcast with slides today at 5:00 p.m. Eastern Time / 2:00 p.m. Pacific Time. To participate by telephone, please dial 877-407-9039 (domestic) or 201-689-8470 (international). The conference ID number is 13700828. A live and archived audio webcast can be accessed through the Investors section of the Company’s website at www.allakos.com. The archived audio webcast will remain available on the Company’s website for 30 days following the conference call.

About Eosinophilic Gastritis, Eosinophilic Duodenitis, and Eosinophilic Esophagitis
Eosinophilic gastritis, eosinophilic duodenitis (previously referred to as eosinophilic gastroenteritis), and eosinophilic esophagitis are severe inflammatory orphan diseases characterized by the presence of high levels of eosinophils in the stomach, duodenum, or esophagus, respectively. Common symptoms of the diseases include severe abdominal pain, nausea, diarrhea, bloating, cramping, early satiety, loss of appetite, vomiting, dysphagia, and weight loss. The current estimated prevalence of eosinophilic gastritis and eosinophilic duodenitis in the United States is approximately 50,000 people. The estimated prevalence of eosinophilic esophagitis in the United States is approximately 150,000 people. There are no treatments approved specifically for these diseases. Treatment with systemic steroids can provide symptomatic improvement, but long-term treatment with steroids is generally not possible due to the numerous side effects. Allakos has received orphan drug designation for antolimab in eosinophilic gastritis, eosinophilic gastroenteritis, and eosinophilic esophagitis.

About Allakos

Allakos is a clinical stage biotechnology company developing antibodies that target immunomodulatory receptors present on immune effector cells involved in allergic, inflammatory, and proliferative diseases. The Company’s lead antibody, antolimab (AK002), targets Siglec-8, an inhibitory receptor selectively expressed on human mast cells and eosinophils. Antolimab has been shown to inhibit mast cells and deplete eosinophils. Inappropriately activated eosinophils and mast cells have been identified as key drivers in a number of severe diseases affecting the gastrointestinal tract, eyes, skin, lungs and other organs. Antolimab has been tested in six clinical studies. In these studies, antolimab eliminated blood and tissue eosinophils, inhibited mast cells and improved disease symptoms in patients with eosinophilic gastritis and/or eosinophilic duodenitis, eosinophilic esophagitis, mast cell gastrointestinal disease, severe allergic conjunctivitis, chronic urticaria, and indolent systemic mastocytosis. For more information, please visit the Company’s website at www.allakos.com.

SOURCE: Allakos