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Preprint WatchMildSeptember 28th, 2026

Engineering CAR-T cells to remodel the mucin-rich cancer cell glycocalyx

Park, S.; Ho, C.; Wolff, A. N.; Fan, Y.; Bouffard, A. A.; Paek, J.; Mucci, A.; Berger, T. R.; Paszek, M. J.; Maus, M. V.

KLK5 cleaves tumour-associated mucins, increasing access to membrane-proximal antigens, and CAR-T cells engineered to display or secrete KLK5 show improved tumour control and prolonged survival versus conventional MUC17 CAR-T cells in xenografts.

Mild contradiction

1 prior failure

One documented clinical failure (Phase 1 or 2) overlaps with the claimed mechanism.

A bioengineering preprint posted to bioRxiv on 27 September 2026 proposes KLK5 as a therapeutic tool rather than a therapeutic target. Park and colleagues identify KLK5 as a human protease that cleaves tumour-associated mucins and increases access to membrane-proximal antigens, then engineer CAR-T cells to display or secrete it, reporting improved tumour control across xenograft models with the strongest survival benefit for KLK5-secreting MUC17 CAR-T cells. The Claidex graph holds one KLK5 failure, ds2325a-klk5-netherton-syndrome-business-decision, in which a KLK5 inhibitor programme for Netherton syndrome was discontinued on a business decision rather than for efficacy or safety. The two efforts point in opposite pharmacological directions, so the failure record does not contradict this claim. It does carry a transferable caution, because the Netherton rationale rests on KLK5 proteolytic activity at epithelial surfaces being tightly coupled to barrier damage, and CAR-T cells engineered to secrete active KLK5 into tissue will meet the same dose-response question in reverse. Severity is set to MILD because the single matching failure was a sponsor decision rather than an efficacy failure.

Abstract excerpt

The dense glycocalyx of cancer cells can restrict immune-cell access to surface antigens and limit CAR-T cell activity. Here, we show that mucin density and epitope position determine how glycocalyx remodeling affects CAR-T cell recognition and killing. We identify KLK5 as a human protease that cleaves tumor-associated mucins, increases access to membrane-proximal antigens, and enhances CAR-T cell function. We then engineer CAR-T cells to display or secrete KLK5, enabling remodeling of the tumor glycocalyx during antigen recognition. KLK5-engineered CAR-T cells improved tumor control across multiple xenograft models, and KLK5-secreting MUC17 CAR-T cells produced the strongest in vivo benefit, prolonging survival compared with conventional MUC17 CAR-T cells. These findings show that CAR-T cells can be engineered to breach the mucin-rich glycocalyx while preserving accessible target epitopes.

Matching Claidex post-mortems

1 of 1 indexed

This is an automated contradiction flag, not an editorial judgment on the preprint's quality. Flags identify where the preclinical literature and the clinical failure record diverge.