Kate Therapeutics Reveals Platform and Pipeline Progress at ASGCT 2024

At the American Society of Gene and Cell Therapy (ASGCT) 2024 meeting, Kate Therapeutics (KateTx), a next-generation gene therapy company, presented preclinical efficacy and safety results on its pipeline and platform (1). These results are intended to support the potential of KateTx’s newest generation, best-in-class MyoAAV (adeno-associated viruses) capsids and gene regulation technology, developed to treat Duchenne muscular dystrophy (DMD), facioscapulohumeral muscular dystrophy (FSHD), and other severe genetic skeletal muscle and heart diseases. The MyoAAV capsids are skeletal muscle and heart-targeted and liver de-targeted.

KateTx is less than a year old, created with a $51 million co-investment from Westlake Village BioPartners and Versant Ventures, with an exclusive license for Astellas Pharmaceuticals to develop and commercialize KT430, a next-generation investigational gene therapy (2). KT430 delivers a working copy of the MTM1 gene through a MyoAAV capsid to treat X-linked myotubular myopathy (XLMTM), a rare and life-threatening neuromuscular disease that causes respiratory failure, severe muscle weakness, and early death.

In the time since its formation, the company has created, via its DELIVER platform, a proprietary class of muscle- and heart-targeted, liver-detargeted MyoAAV-LD capsids with improved potency and selectivity in non-human primates (NHPs). KateTx selected KT809 as a development candidate to treat DMD, combining MyoAAV-LD 6.1, a sixth-gen capsid, with a regulatory element created to express the transgene in skeletal muscle and heart in primates.

DMD is a fatal genetic disorder, characterized by progressive muscle weakness and deterioration, and is the most common form of muscular dystrophy. The disease leads to loss of ambulation, cardiomyopathy, ventilatory compromise, and death by early adulthood. At ASGCT, KateTx presented data on its DMD development candidate, which showed higher and more consistent expression at lower doses in NHPs than a surrogate version of an FDA-approved DMD gene therapy. High and consistent microdystrophin protein express is needed across muscle fibers to protect against injury and death in DMD, and KateTx’s candidate showed high and consistent levels of microdystrophin in skeletal and cardiac muscles at a dose three times lower than the surrogate. The company’s candidate also had 27 times lower vector genomes per nucleus in the liver as compared to animals injected with the surrogate.

KateTx also presented preclinical data from its program for FSDH, a common muscular dystrophy stemming from toxic expression of the DUX4 protein in skeletal muscle. In vitro, KateTx’s MyoAAV-LD mediated RNA interference (RNAi) gene therapy candidate significantly decreased levels of DUX4 in FSHD patient myotubes, with no off-target effects. When tested in mice, the therapy lowered DUX4 target gene expression, leading to dose-dependent improvements of muscle function.

“Both DMD and FSHD are challenging diseases—they require delivery of therapeutic cargoes to a substantial tissue mass, and expression of significant amounts of protein uniformly and durably across skeletal muscle fibers and cardiomyocytes in the case of DMD, and effective inhibition of toxic DUX4 expression in skeletal muscle in the case of FSHD,” said Katherine A. High, M.D., visiting professor at Rockefeller University, professor Emerita of pediatrics at the Perelman School of Medicine at the University of Pennsylvania and member of the KateTx Scientific Advisory Board, in a Kate press release (1). “The clinical evaluation of these novel bioengineered capsids is in my judgment one of the most exciting near-term developments in our field and I look forward to these programs moving into clinical development.”

References

1. Kate Therapeutics. Kate Therapeutics Unveils Platform and Pipeline Progress at American Society of Gene & Cell Therapy 2024 Annual Meeting. Press Release, May 9, 2024.
2. Astellas. Astellas and Kate Therapeutics Announce Exclusive License Agreement for KT430. Press Release, June 8, 2024.