Letter: Supporting the Role of Enzyme Therapy in Management of Coeliac Disease—Authors' Reply

We thank Prof. Macrae for his supportive letter [1] regarding our review.

As emphasised in our article [2], dietary supplements claiming to digest gluten, or gluten immunogenic peptides, are not approved as treatments for coeliac disease. Indeed, there is no pharmaceutical that has regulatory approval as a treatment for coeliac disease. Furthermore, the draft guidance from the FDA highlights that treatment receiving approval would be in conjunction with a gluten-free diet. There remain safety concerns that a product claim of protection against gluten could be interpreted by patients as a licence to liberalise their gluten-free diet.

Many investigational products for coeliac disease have shown promise in preclinical and early clinical trials but failed in larger studies employing robust patient-reported outcome instruments to assess symptoms and rigorous quantitative histology. It would be concerning if Gluteguard were marketed as an enzyme supplement intended to mitigate accidental or intentional gluten exposure in patients with coeliac disease without robust multiple independent clinical trials to support disease-specific therapeutic claims.

Prof. Macrae's statement that ‘Enzyme therapies like caricain offer protection against gluten before it triggers immune responses’ [1] is concerning to us because it implies that Gluteguard is a ‘therapy’ with confirmed clinical benefits. While the small clinical ‘proof-of-concept’ studies involving Gluteguard are interesting, development of this product over the past 20+ years would appear to be as a dietary supplement but not as a safe and effective therapeutic. As such, therapeutic claims for Gluteguard are at best premature.

The level of scientific evidence required for therapeutic claims is significantly higher than that of academic publication, no matter how high or low the reputation of a medical journal.

The authors' declarations of personal and financial interests are unchanged from those in the original article [2].

Erin R. Bonner: writing – review and editing. Werner Tschollar: writing – review and editing. Robert Anderson: writing – original draft. Sulayman Mourabit: writing – original draft.

The authors declare no conflicts of interest.

This article is linked to Bonner et al. papers. To view these articles, visit, https://doi.org/10.1111/apt.70014 and https://doi.org/10.1111/apt.70182.