Introduction
TAK-062 is an orally delivered glutenase computationally designed to degrade immunogenic gliadin peptides. A phase 2 trial of TAK-062 (NCT05353985) did not meet the primary or secondary endpoints; however, the results may still be used to inform endpoints for future clinical studies in celiac disease. This study assessed the trial data for multiple histologic endpoints and determined the outcomes and relative performance of each.
Aims & Methods
The efficacy of TAK-062 vs placebo was assessed over a 24-week treatment period. Eligible patients were aged ≥18 years and had biopsy-confirmed celiac disease defined as a villous height to crypt depth ratio (Vh:Cd) of <2.5 at screening endoscopy (Week –4). All patients received simulated inadvertent gluten exposure (SIGE), consisting of a bar containing 500 mg of gluten three times per week throughout the treatment period. Duodenal biopsies taken at baseline and Week 24 were fixed in formalin and stained with hematoxylin and eosin for Vh:Cd analysis. Vh:Cd measurements were made by multiple readers with a proprietary digital pathology platform and averaged. CD3- and CD8-stained biopsy samples were used to count intraepithelial lymphocytes (IELs) and CD8 T cells, respectively, using a proprietary semi-automated counting software. The above measures were used to calculate two composite endpoints: (i) Vh:Cd and IEL counts (VCIEL), and (ii) Quantitative-Mucosal Algorithmic Rules for Scoring Histology (Q-MARSH). Qualitative assessment of Marsh–Oberhuber classification was conducted by a single pathologist. The variability and effect size of each outcome was determined.
Results
Analysis of the source of variability in the Vh:Cd measurement showed that 52% of the variability was at the patient level and 23% at the biopsy level. Only 1% of the variability was due to reader effects. Most other histology endpoints showed a similar response trend as observed with Vh:Cd. Determination of Vh, Cd, IEL counts, VCIEL, Q-MARSH and Marsh–Oberhuber scoring all showed significant worsening relative to baseline with TAK-062 treatment. Comparison of effect sizes for each endpoint showed that no endpoint outperformed Vh:Cd. Use of a statistically meaningful target criterion for response (Vh:Cd change of 0.4) found that 13.3% of patients in the placebo arm and 3.4% of patients in the TAK-062 treatment arm achieved this target response. Using a stringent remission criterion (Vh:Cd ≥ 2.7), 8.3% of the placebo arm and 1.7% of the TAK-062 arm achieved remission.
Conclusion
Although TAK-062 did not demonstrate efficacy in the phase 2 trial, learnings from this study emphasize the need for well-trained readers with clear scoring criteria to help to minimize variability in quantitative scoring. Furthermore, Vh:Cd shows good performance and is recommended as a key endpoint for assessing changes in gut architecture in celiac disease studies.
Disclosure
JM, JC, MZ, and DAL, are employees and shareholders of Takeda Development Center Americas, Inc. and receive stock or stock options.
JI is the founder and owner of Jilab, Inc., which received funding from Takeda for work undertaken as part of this study, is a full Professor at Tampere University, Medical Faculty, and has a consulting agreement with Takeda.
AV has nothing to disclose.
MER is a consultant for Alimentiv, Bristol Myers Squibb, Perspectum, Teva Pharmaceutical Industries Ltd., Anokion and Takeda, and has received a grant from AstraZeneca.