Tenaya Therapeutics Presents Encouraging New Clinical & Preclinical Data From HDAC6 Inhibitor Program for the Potential Treatment of Heart Failure With Preserved Ejection Fraction 

Tenaya Therapeutics, Inc. recently released new data for TN-301 at the 2023 Heart Failure Society of America (HFSA) Annual Scientific Meeting. TN-301 is Tenaya’s highly selective small molecule inhibitor of histone deacetylase 6 (HDAC6) being developed for the potential treatment of heart failure with preserved ejection fraction (HFpEF).

“TN-301 continues to generate promising early data as a differentiated candidate for the treatment of HFpEF, a form of heart failure with few treatment options and unacceptably low survival rates. The first-in-human data from our Phase 1 study of TN-301 demonstrated safety and tolerability in healthy participants with dose-proportional pharmacokinetics and robust target engagement,” said Whit Tingley, MD, Tenaya’s Chief Medical Officer. “The attractive therapeutic profile seen in our Phase 1 trial of healthy participants and the additive benefits observed preclinically of HDAC6 inhibition in combination with empagliflozin support the potential for TN-301 to be utilized as a single agent or in combination with an emerging standard of care. Taken together, these data support continued development of TN-301 as a potential treatment to address the many HFpEF patients underserved by today’s treatment options.”

Results from the Phase 1 clinical trial of TN-301 were presented in an ePoster, Phase 1 Clinical Trial Of TN-301, A Highly Selective HDAC6 Inhibitor with Potential in HFpEF, Shows Target Engagement (#417). Tenaya initiated the randomized, double-blind, placebo-controlled Phase 1 clinical trial in September 2022 to assess the safety and tolerability of escalating, oral doses of TN-301, as well as pharmacokinetics (PK) and pharmacodynamics (PD) measures. The Phase 1 trial enrolled a total of 72 healthy adult participants in two stages. In Stage 1, participants received single ascending doses (SAD) of either TN-301 at doses ranging from 1mg – 700 mg or placebo. Tubulin acetylation was previously established as a relevant PD marker of HDAC6 inhibition in preclinical studies and utilized in the Phase 1 clinical trial to confirm target engagement. Upon achieving evidence of target engagement at single doses of 5 mg, participants were enrolled in Stage 2 and received multiple ascending doses (MAD) of TN-301 at once daily doses of 25 mg, 100 mg, and 300 mg for 14 days.

Key Findings:

• TN-301 was generally well tolerated across the broad range of doses studied, with no dose-limiting toxicities or serious adverse events observed. The most common adverse events observed were related to gastrointestinal disturbances. These occurred with similar frequency among those who received placebo or TN-301 and did not increase with TN-301 dose. All participants completed the study.
• PK results showed overall dose proportionality in both the SAD and MAD stages of the study with a half-life supportive of once-daily dosing.
• Robust HDAC6 inhibition was observed and increasing doses and exposures with TN-301 correlated with increasing PD effects. Plasma exposure and target engagement observed in this healthy participant study met or exceeded those required for maximal efficacy in preclinical studies.
• There were no changes in histone acetylation with TN-301, underscoring the selectivity of TN-301 for HDAC6 and potentially reducing the risk of off target effects observed with less selective HDAC6 inhibitors or pan-HDAC inhibition.
• Future studies of TN-301 in HFpEF patients may evaluate a range of doses starting at approximately 25 mg and higher.

The ePoster titled, Co-Administration of Inhibitors of HDAC6 and SGLT2 in Murine HFpEF Models Results in Additive Improvements in Cardiac Structural and Functional Measures (#104), describes an effort by Tenaya researchers to examine the effect of combining TYA-018 (an HDAC6 inhibitor structurally and functionally similar to TN-301) with empagliflozin (a sodium-glucose cotransporter-2 (SGLT2) inhibitor) which is approved for the treatment of HFpEF) in the company’s proprietary HFpEF mouse model. This study compared healthy controls with those treated with TYA-018 and empagliflozin administered alone or in combination vs. untreated HFpEF mice.

Key findings:

• Evidence of additive benefits at or nearing that of healthy controls were observed in all treatment groups at eight weeks, but more substantially with combination treatment, across multiple measures of diastolic function (E/e’, E/A, end diastolic pressure) without negative consequences to ejection fraction.
• At a gene level, an extensive reversal of disease toward healthy controls was observed in TYA-018 and combination groups, but less so in the empagliflozin group. A gene set enrichment analysis of pathway and functional level HFpEF changes provided insights on the distinct impact of HDAC6 inhibition on disease pathophysiology compared to SGLT2 inhibition, with TYA-018 demonstrating a greater impact on improving metabolism, oxidative stress and inflammation.

HFpEF is characterized by a stiffening of the heart muscle resulting in an inability for the left ventricle to relax properly during normal heart rhythm, referred to as diastolic dysfunction. There are several cellular processes thought to underly the pathophysiology of HFpEF including increases in fibrosis and inflammation and defects in metabolism. Although HFpEF accounts for approximately 50% of all heart failures, there are few proven treatment options.

TN-301 is Tenaya’s highly specific first-in-class small molecule histone deacetylase (HDAC) 6 inhibitor, initially being developed for the potential treatment of HFpEF. TN-301 has a multi-modal mechanism of action that includes modifying cytoskeletal and other proteins to coordinate cellular processes. In preclinical studies, TN-301 has been shown to reverse many of the signs and symptoms of HFpEF, with evidence of improved cardiac function and improved glucose tolerance and reduced inflammation and fibrosis.

Tenaya Therapeutics is a clinical-stage biotechnology company committed to a bold mission: to discover, develop, and deliver potentially curative therapies that address the underlying drivers of heart disease. Leveraging its integrated and interrelated Gene Therapy, Cellular Regeneration and Precision Medicine platforms and proprietary core capabilities, the company is advancing a pipeline of novel therapies with diverse treatment modalities for rare genetic cardiovascular disorders and more prevalent heart conditions. Tenaya’s most advanced candidates include TN-201, a gene therapy for MYBPC3-associated hypertrophic cardiomyopathy (HCM), TN-401, a gene therapy for PKP2-associated arrhythmogenic right ventricular cardiomyopathy (ARVC), and TN-301, a small molecule HDAC6 inhibitor being initially developed for heart failure with preserved ejection fraction (HFpEF). Tenaya also has multiple early-stage programs progressing through preclinical development. For more information, visit www.tenayatherapeutics.com.