Lirentelimab met histologic co-primary endpoints but missed symptomatic co-primary endpoints in both ENIGMA and KRYPTOS studies
REDWOOD CITY, CA, USA I December 21, 2021 I Allakos Inc. (the “Company” or “Allakos”) (Nasdaq: ALLK), a biotechnology company developing lirentelimab (AK002) for the treatment of eosinophil and mast cell-related diseases, today reported data from ENIGMA 2, a 24-week Phase 3 randomized, double-blind, placebo-controlled study of lirentelimab in patients with biopsy confirmed eosinophilic gastritis (EG) and/or eosinophilic duodenitis (EoD) and KRYPTOS, a 24-week Phase 2/3 randomized, double-blind, placebo-controlled study of lirentelimab in patients with biopsy-confirmed eosinophilic esophagitis (EoE). Both ENIGMA 2 and KRYPTOS studies met their histologic co-primary endpoints, but did not achieve statistical significance on the patient reported symptomatic co-primary endpoints.
“We are deeply disappointed that the studies did not achieve their symptomatic endpoints,” said Robert Alexander, PhD, Chief Executive Officer of Allakos. “The company is grateful to the patients with eosinophilic gastrointestinal diseases (EGIDs) and to the investigators who participated in the ENIGMA and KRYPTOS trials.”
Dr. Craig Paterson, MD, Chief Medical Officer of Allakos added, “Although the EGID results are surprising and disappointing, we will continue to analyze the data to understand the results and to determine the path forward for lirentelimab in EGIDs. At present we intend to continue our development efforts with subcutaneous lirentelimab in atopic dermatitis, chronic spontaneous urticaria, and asthma. The atopic dermatitis study is underway and we plan to initiate chronic spontaneous urticaria and asthma studies in 2022 and will continue to advance other programs in our preclinical pipeline.”
ENIGMA 2 Phase 3 Topline Results
The co-primary endpoints for the Phase 3 study were (1) the proportion of patients achieving histologic resolution (defined as ≤4 eosinophils (eos) / high powered field (hpf) in 5 hpfs in the stomach and/or ≤15 eos/hpf in 3 hpfs in the duodenum) and (2) symptomatic improvement as measured by absolute change in the six symptom total symptom score (TSS).
| Co-Primary Endpoints | Lirentelimab (n=91) | Placebo (n=89) |
| Histology Endpoint: Proportion of responders as determined by gastric or duodenal tissue eosinophil counts1 |
84.6% (p<0.0001) |
4.5% |
| Symptom Endpoint: Absolute mean change in patient reported Total Symptom Score (TSS-6)2 |
Baseline TSS: 29.5 | Baseline TSS: 27.7 |
| -10.0 (p=0.343) |
-11.5 |
1 = A responder is a patient achieving the following peak eosinophil counts: eosinophil count ≤4 cells per hpf in 5 gastric hpf and/or eosinophil count ≤15 cells per hpf in 3 duodenal hpf. Endpoint assessed at end of Week 24.
2 = TSS-6 is daily patient reported symptom questionnaire assessing 6 symptoms (abdominal pain, nausea, bloating, early satiety, abdominal cramping, and loss of appetite) on a scale from 0 to 10. Endpoint assessed as mean change from baseline to Weeks 23-24.
The safety results of the trial were generally consistent with previously reported lirentelimab studies. No new safety signals were observed. Mild to moderate infusion-related reactions (including flushing, feeling of warmth, headache, nausea, and/or dizziness) occurred in 34% of lirentelimab-treated patients and 14% of placebo-treated patients.
KRYPTOS Phase 2/3 Topline Results
The co-primary endpoints for the Phase 2/3 study were (1) the proportion of patients achieving histologic resolution (defined as ≤6 eosinophils (eos) / high powered field (hpf) in the esophagus) and (2) symptomatic improvement as measured by absolute change in dysphagia symptom questionnaire (DSQ).
| Co-Primary Endpoints | Lirentelimab High Dose (n=91) |
Lirentelimab Low Dose (n=93) |
Placebo (n=92) |
| Histologic Endpoint: Proportion of responders (eos ≤6 /hpf) as determined by esophageal tissue eosinophil counts 1 |
87.9% (p<0.0001) |
92.5% (p<0.0001) |
10.9% |
| Symptom Primary Endpoint: Absolute mean change in patient reported Dysphagia Symptom Questionnaire (DSQ)2 |
DSQ Baseline: 34.2 |
DSQ Baseline: 36.4 |
DSQ Baseline: 35.2 |
| -17.4 (p=0.237) |
-11.9 (p=0.247) |
-14.6 |
1 = A responder is a patient achieving the following peak eosinophil counts: ≤6 eosinophils (eos) / high powered field (hpf) in 1 hpf in the esophagus. Endpoint assessed at end of Week 24.
2 = DSQ is a patient reported symptom questionnaire assessing difficulty swallowing. Endpoint assessed as absolute mean change from baseline to Weeks 23-24.
The safety results of the trial were generally consistent with previously reported lirentelimab studies. No new safety signals were observed. Mild to moderate infusion-related reactions (including flushing, feeling of warmth, headache, nausea, and/or dizziness) occurred in 39% of high dose lirentelimab- treated patients, 26% of low dose lirentelimab-treated patients and 12% of placebo-treated patients.
Phase 3 ENIGMA 2 Study Design
The randomized, double-blind, placebo-controlled Phase 3 trial of intravenous lirentelimab enrolled 180 patients with EG and/or EoD. Patients were required to be moderately to severely symptomatic based on a patient reported symptom questionnaire and have biopsy-confirmed eosinophilia of the stomach (≥30 eosinophils/hpf in 5 hpfs) and/or duodenum (≥30 eosinophils/hpf in 3 hpfs). Patients were randomized 1:1 to receive: 1.0 mg/kg of lirentelimab for the first month followed by five doses of 3.0 mg/kg given monthly or (b) 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, loss of appetite) each on a scale from 0 to 10 (TSS). Co-primary endpoints were (1) proportion of responders with ≤4 eos/hpf in 5 hpfs in the stomach and/or ≤15 eos/hpf in 3 hpfs in the duodenum at the end of week 24 and (2) absolute change from baseline in TSS at weeks 23-24.
Phase 2/3 KRYPTOS Study Design
The randomized, double-blind, placebo-controlled Phase 2/3 trial of intravenous lirentelimab enrolled 276 patients with EoE. Patients were required to be moderately to severely symptomatic based on the dysphagia symptom questionnaire (DSQ) and have biopsy-confirmed eosinophilia of the esophagus (≥15 eosinophils in 1 hpf). Patients were randomized 1:1:1 to receive: 1.0 mg/kg of lirentelimab for the first month followed by five doses of 3.0 mg/kg given monthly (b) monthly 1.0 mg/kg of lirentelimab (c) a monthly placebo. Disease symptoms were measured daily using a patient reported symptom questionnaire that assessed difficulty swallowing. Co-primary endpoints were (1) proportion of responders with ≤6 eosinophils in 1 hpf in the esophagus and (2) absolute change in dysphagia symptom questionnaire from baseline.
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, lirentelimab (AK002), is an investigational medicine that is being evaluated in clinical studies, including in EGIDs and a Phase 2 study in atopic dermatitis. The Company plans to initiate a Phase 2/3 study in chronic spontaneous urticaria and a Phase 2 study in asthma in the middle of 2022 and Q4 2022, respectively. Lirentelimab targets Siglec-8, an inhibitory receptor selectively expressed on human eosinophils and mast cells. 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. For more information, please visit the Company’s website at www.allakos.com.
SOURCE: Allakos
