Allakos Inc. reported data from EoDyssey, a 24-week, Phase 3, randomized, double-blind, placebo-controlled study of lirentelimab in patients with biopsy confirmed eosinophilic duodenitis (EoD). The trial met its histologic co-primary endpoint, but it did not achieve statistical significance on the patient reported symptomatic co-primary endpoint, in both the intent to treat (ITT) population and in a prespecified subpopulation. The prespecified subpopulation was based on a post hoc analysis of the Company's phase 3 ENIGMA2 study and excluded certain patients with conditions that could confound the patient reported symptomatic endpoint (e.g., non-eosinophilic/non-mast cell driven esophageal disorders or active irritable bowel syndrome).

Although positive numerical trends in the symptomatic endpoint were observed in this prespecified subpopulation, the results were not statistically significant. The safety results of the trial were generally consistent with previously reported intravenous lirentelimab studies. Mild to moderate infusion-related reactions (including flushing, feeling of warmth, headache, nausea, and/or dizziness) occurred in 19.6% of lirentelimab-treated patients and 14.9% of placebo-treated patients.

Currently Allakos is not planning to conduct additional studies in eosinophilic gastrointestinal diseases, but may do so in the future. Allakos is focusing development efforts for lirentelimab in atopic dermatitis and chronic spontaneous urticaria and on AK006. Allakos Development ProgramsAllakos is conducting a Phase 2 randomized, double-blind, placebo-controlled study of subcutaneous lirentelimab in patients with moderate-to-severe atopic dermatitis and a Phase 2b randomized, double-blind, placebo-controlled study of subcutaneous lirentelimab in patients with chronic spontaneous urticaria.

The Company anticipates reporting topline data from these studies in the second half of 2023. Additionally, Allakos is advancing AK006, an anti-Siglec-6 antibody that selectively inhibits mast cells, including KIT-mediated signaling, into IND enabling studies and plans to initiate a Phase 1 study in healthy volunteers in the first half of 2023. EoDyssey Phase 3 Design The randomized, double-blind, placebo controlled Phase 3 trial of intravenous lirentelimab enrolled 93 patients with moderate to severe symptoms (based on a patient reported symptom questionnaire) and biopsy-confirmed eosinophilia of the duodenum (>=30 eosinophils/hpf in 3 hpfs) without eosinophilia of the stomach (defined as having less than 30 eosinophils/hpf in 5 hpfs).

Patients were randomized 1:1 to receive: 3.0 mg/kg of lirentelimab given monthly or a monthly placebo. Disease symptoms were measured daily using a patient reported symptom questionnaire that scored 6 symptoms (abdominal pain, nausea, bloating, early satiety, abdominal cramping, and loss of appetite) each on a scale from 0 to 10 (TSS). The co-primary endpoints for the Phase 3 study were (1) the proportion of patients achieving histologic response (defined as <15 eosinophils (eos) /high powered field (hpf) in 3 hpfs in the duodenum) and (2) symptomatic improvement as measured by mean absolute change in the six-symptom total symptom score (TSS).