GlobeNewswire Inc | Oct 26, 2020 07:00AM EDT

October 26, 2020

-- Subcutaneous formulation of lirentelimab was safe and well tolerated and demonstrated sustainedeosinophil suppressionsupporting once monthly dosing--

-- Management to host conference call and webcast today at8:00 am ET--

REDWOOD CITY, Calif., Oct. 26, 2020 (GLOBE NEWSWIRE) -- Allakos Inc. (the Company) (Nasdaq: ALLK), a biotechnology company developing lirentelimab (AK002) for the treatment of eosinophil and mast cell-related diseases, today announced results from a Phase 1 Study of subcutaneously administered lirentelimab in healthy volunteers. Based on these results, Allakos intends to investigate monthly dosing of the subcutaneous (SC) formulation of lirentelimab in patients with eosinophilic gastritis, eosinophilic duodenitis, eosinophilic esophagitis and other diseases.

Study Design Phase 1 Subcutaneous Lirentelimab in AdultHealthy VolunteersThe randomized, double-blind, placebo-controlled, single dose, dose ranging Phase 1 Study was designed to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of subcutaneous lirentelimab in healthy volunteers over 85 days. Subjects enrolled in subcutaneously administered cohorts received a single SC dose of one of the following: 0.3, 1.0, 3.0, 5.0 mg/kg of lirentelimab, a 2 mL SC dose containing 300 mg of lirentelimab, or placebo. Bioavailability of SC lirentelimab was determined by comparing SC cohorts to cohorts that received intravenously (IV) administered lirentelimab.

Results: Phase 1 Subcutaneous Lirentelimab in AdultHealthy VolunteersBioavailability of SC lirentelimab was 63 percent. Subcutaneously administered lirentelimab resulted in extended eosinophil suppression at all dose levels tested. At dose levels of 3.0 and 5.0 mg/kg and with the fixed dose of 300 mg, SC lirentelimab resulted in eosinophil suppression in all subjects through Day 85.

Blood Eosinophil Levels Over Time

Median Blood Eosinophils 10^3/mL

Route Dose Cohort n BL 1 hr 3 hr Day 15 Day 35 Day 56 Day 85

SC Placebo 10 100 100 200 200 100 200 100

0.3 mg/kg 6 110 200 20 0 0 50 100

1.0 mg/kg 6 150 0 0 0 0 0 50

3.0 mg/kg 6 150 0 0 0 0 0 0

5.0 mg/kg 6 100 0 0 0 0 0 0

300 mg 6 100 0 0 0 0 0 0

IV 1.0 mg/kg 6 100 0 0 0 0 0 0

3.0 mg/kg 12 100 0 0 0 0 0 0

Subcutaneously administered lirentelimab was well tolerated. Across all SC and IV lirentelimab cohorts there were no serious adverse events, no injection site reactions, no injection reactions and no infusion-related reactions. One subject receiving placebo reported an injection reaction (mild flushing two hours post-injection).

Conference Call and Live WebcastThe Company will host a conference call and webcast with slides today at 8:00 a.m. Eastern Time / 5:00 a.m. Pacific Time. To participate by telephone, please dial 877-407-9039 (domestic) or 201-689-8470 (international). The conference ID number is 13712474. 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 EsophagitisEosinophilic gastritis, eosinophilic duodenitis (previously referred to as eosinophilic gastroenteritis), and eosinophilic esophagitis are chronic, often severe, inflammatory diseases characterized by the presence of high levels of eosinophils in the stomach, duodenum, or esophagus, respectively. Common symptoms of the diseases include 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 inthe United Statesis approximately 50,000 people. The estimated prevalence of eosinophilic esophagitis inthe United Statesis approximately 150,000 people. The Company believes that these diseases may be significantly under-diagnosed, or misdiagnosed, as other gastrointestinal diseases. 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.Allakoshas received orphan drug designation for lirentelimab in eosinophilic gastritis, eosinophilic gastroenteritis, and eosinophilic esophagitis.

AboutAllakosAllakosis a clinical stage biotechnology company developing antibodies that target immunomodulatory receptors present on immune effector cells involved in allergic, inflammatory, and proliferative diseases. The Companys lead antibody, lirentelimab (AK002), is being evaluated in a Phase 3 study in eosinophilic gastritis (EG) and/or eosinophilic duodenitis (EoD) and a Phase 2/3 study in eosinophilic esophagitis (EoE). Lirentelimabtargets Siglec-8, an inhibitory receptor selectively expressed on human mast cells and 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. Lirentelimab has been tested in multiple clinical studies. In these studies, lirentelimab eliminated blood and tissue eosinophils, inhibited mast cells and improved disease symptoms in patients with EG and/or EoD, EoE, 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.

Forward-Looking StatementsThis press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 as contained in Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Such forward-looking statements include, but are not limited to, Allakos progress and business plans, the expected timing of anticipated study results and plans relating to its future clinical trials. Such statements are subject to numerous important factors, risks and uncertainties that may cause actual events or results to differ materially from current expectations and beliefs, including but not limited to: Allakos stages of clinical drug development; Allakos ability to timely complete clinical trials for, and if approved, commercialize lirentelimab (AK002), its lead compound; Allakos ability to obtain required regulatory approvals for its product candidates; uncertainties related to the enrollment of patients in its clinical trials; Allakos ability to demonstrate sufficient safety and efficacy of its product candidates in its clinical trials; uncertainties related to the success of later-stage clinical trials, regardless of the outcomes of preclinical testing and early-stage trials; market acceptance of Allakos product candidates; uncertainties related to the projections of the size of patient populations suffering from the diseasesAllakosis targeting; Allakos ability to advance additional product candidates beyond lirentelimab; Allakos ability to obtain additional capital to finance its operations; and other important risk factors set forth in Allakos most recent Annual Report on Form 10-K filed with theSEConFebruary 25, 2020, Quarterly Report on Form 10-Q filed with theSEConAugust 10, 2020and future reports to be filed with theSEC. These documents contain and identify important factors that could cause the actual results forAllakosto differ materially from those contained in Allakos forward-looking statements. Any forward-looking statements contained in this press release speak only as of the date hereof, andAllakosspecifically disclaims any obligation to update any forward-looking statement, except as required by law. These forward-looking statements should not be relied upon as representing Allakos views as of any date subsequent to the date of this press release.

Source: Allakos Inc.

Investor Contact:Adam Tomasi, President and COOir@allakos.com

Media Contact:Denise Powelldenise@redhousecomms.com