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Zehna Therapeutics is developing non-bactericidal inhibitors of selected gut microbial enzymes clinically and mechanistically linked with cardiometabolic diseases. Our lead compounds inhibit the gut microbial enzyme CutC lyase, preventing the conversion of dietary choline to trimethylamine (TMA) and subsequently to trimethylamine N-oxide (TMAO) within the host.

High systemic levels of TMAO have been linked to accelerated development of both cardiovascular and chronic kidney disease, as demonstrated in large-scale clinical cohort studies and extensive animal models of chronic metabolic diseases. Additionally, elevated TMAO, which often accompanies obesity, may contribute to sustained weight gain and promote renal oxidative stress and inflammation underlying obesity-associated chronic kidney disease (CKD). CKD is our lead indication.

CutC Lyase Inhibitor

How it works

  • Bacteria in the gut possess an enzyme, CutC lyase, that converts dietary and endogenous choline into TMA
  • TMA is absorbed and transformed by human liver enzymes into TMAO
  • At Zehna, we are designing small molecules to inhibit CutC lyase and prevent the formation of TMA and TMAO, with the aim of slowing cardiometabolic disease progression

What makes our approach different

  • We are targeting a driver of disease, rather than a symptom
  • We employ well-established drug discovery principles to inhibit a bacterial enzyme target with a small molecule
  • We have developed an orally administered formulation for release in the colon, thus limiting systemic absorption
1 (Evenepoel 2017)
2 (Kanbay 2018)
3 (Sumida 2019; Mahmoodpoor 2017; Sampaio-Maia 2016)
4 (Lin 2017; Vaziri 2013)
5 (Tang 2015; Rhee 2013; Gruppen 2017; Zhang 2021)
6 (Loo 2021; Zeisel 2017)
7 (Dolphin 1997; Bennet 2013; Schmidt 2020; Gatarek 2021)
8 (Stubbs 2016; Missailidis 2016; Kim 2016; Zhou 2021; Tang 2015; Gupta 2020; Fang 2021; Lai 2021; Kapetanaki 2021; Zhang 2021)
9 (Roberts 2018; Gupta 2020; Gatarek 2021)

Chronic Kidney Disease (CKD)

CKD is Common, Serious and Costly

CKD is prevalent in individuals with type 2 diabetes mellitus (T2DM) and hypertension:

  • >33 million people in U.S with T2DM2; 24.5% or 8 million have both T2DM and stage 3 – 4 CKD2
  • ~50% people in U.S. with hypertension1; 24% have their hypertension under control1; ~3 million people with both hypertension and stage 3 – 4 CKD
  • $20.96B global sales forecast in CKD market by 20283
1 Kovesdy Kidney International, 2022
3 Data Bridge

11 Million People with Stage 3-4 CKD

Timeline of Discoveries Establishing TMAO as a Driver of CKD

  • Discovery

    Dr Stanley Hazen and team discover the relationship between gut flora-dependent metabolism of dietary phosphatidylcholine and CVD pathogenesis (ref: Wang, et al 2011).

  • 2013
  • Framingham Heart Study

    In a large cohort from the Framingham Heart Study, elevated circulating levels of both choline and TMAO were observed to predict the incident development of CKD in subjects with normal renal function at the time of enrollment and sample collection (ref: Rhee, 2013)

  • 2015
  • Risk of Coronary Atherosclerosis

    Plasma TMAO levels are elevated in CKD patients and increase the risk of coronary atherosclerosis burden (ref: Stubbs, et al 2016).

  • 2016
  • CanPREDICCT Cohort

    In the CanPREDICCT cohort, CKD stage 3 – 5 patients with elevated TMAO (>12 mM) have an increased risk of CV and ischemic heart events (Kim, et al 2016).

  • 2018
  • Selective Targeting

    Selective targeting of gut microbiota-dependent TMAO generation using small molecules that inhibit CutC prevents adverse renal structural and functional alterations in an animal model and may be useful in subjects at risk for CKD (ref: Gupta, et al 2020).

  • 2021
  • Severe Renal Dysfunction

    An elevated TMAO level reflects higher levels of hypertension and more severe renal dysfunction (Zhou, et al 2021)

  • 2023
  • Human Cohort Data

    TMAO is positively associated with mortality, especially due to cardiovascular and renal disease in a diverse multi-ethnic population (ref: Wang et al 2023)

  • 2023
  • 2011
  • Hypothesis

    Hypothesized that a potential mechanism for conferring protection from cardiovascular disease and heart failure could be prevention of TMAO accumulation (ref: Tang, et al 2013).

  • 2013
  • Plasma TMAO Levels

    Plasma TMAO levels are both elevated in patients with CKD and portend poorer long-term survival; chronic dietary exposures that increase TMAO directly contributes to progressive renal fibrosis and dysfunction in animal models (ref: Tang, et al 2015).

  • 2016
  • Plasma TMAO Level is a Mortality Predictor

    Plasma TMAO level is inversely related to renal function, directly related to renal inflammation and is an independent predictor of mortality in CKD stage 3 – 5 patients (Missailidis, et al 2016).

  • 2016
  • Identification

    Identification of non-bactericidal gut microbe-targeted small molecules that inhibit CutC and reduce thrombosis potential in CV animal models (ref: Roberts, et al 2018).

  • 2020
  • Continuous Outcomes Variables

    In meta-analyses of continuous outcomes variables, advanced CKD was associated with high concentrations of TMAO; increased TMAO was associated with decreased eGFR and increased UACR, serum creatinine and blood urea nitrogen (Zeng, et al 2021).

  • 2021
  • AAA

    Elevated TMAO was associated with increased abdominal aortic aneurysm (AAA) incidence and growth in two independent patient cohorts (N = 2129 total).  Inhibition of microbiome-derived TMAO may serve as a novel therapeutic approach for AAA treatment where none currently exist. (ref: Benson et al 2023).

  • 2023
  • Machine learning

    Machine learning was used to examine a multitude of phenotypes in 1,714 adults comprising the MetaCardis epidemiological cohort. Mediation analysis within this data set suggested a causal relationship between TMAO and kidney function that was corroborated in preclinical models where previous TMAO exposure increased kidney scarring, fibrosis, and damage. (ref: Andrikopoulos et al 2023)

  • Wang Z, Klipfell E, Bennett BJ, et al. Gut flora metabolism of phosphatidylcholine promotes cardiovascular disease. Nature. 2011; 472:57 – 63.
  • Tang WH, Wang Z, Levison BS, et al. Intestinal microbial metabolism of phosphatidylcholine and cardiovascular risk. N Engl J Med. 2013 Apr 25;368(17):1575-84.
  • Rhee EP, Clish CB, Ghorbani A, et al. A combined epidemiologic and metabolomic approach improves CKD prediction. J Am Soc Nephrol. 2013 Jul;24(8):1330-8.
  • Tang WH, Wang Z, Kennedy DJ, et al. Gut microbiota-dependent trimethylamine N-oxide (TMAO) pathway contributes to both development of renal insufficiency and mortality risk in chronic kidney disease. Circ Res. 2015;116(3):448-455.
  • Stubbs JR, House JA, Ocque AJ, et al. Serum trimethylamine-N-oxide is elevated in CKD and correlates with coronary atherosclerosis burden. J Am Soc Nephrol. 2016;27(1):305-313.
  • Kim RB, Morse BL, Djurdjev O, et al.; CanPREDDICT Investigators. Advanced chronic kidney disease populations have elevated trimethylamine N-oxide levels associated with increased cardiovascular events. Kidney Int. 2016;89(5):1144-1152.
  • Missailidis C, Hällqvist J, Qureshi AR, et al. Serum trimethylamine-N-oxide is strongly related to renal function and predicts outcome in chronic kidney disease. PLoS One. 2016;11(1):e0141738.
  • Roberts AB, Gu X, Buffa JA, et al. Development of a gut microbe-targeted nonlethal therapeutic to inhibit thrombosis potential. Nat Med. 2018;24(9):1407-1417.
  • Gupta N, Buffa JA, Roberts AB, et al. Targeted inhibition of gut microbial trimethylamine n-oxide production reduces renal tubulointerstitial fibrosis and functional impairment in a murine model of chronic kidney disease. Arterioscler Thromb Vasc Biol. 2020;40(5):1239-1255.
  • Zeng Y, Guo M, Fang X, et al. Gut microbiota-derived trimethylamine N-oxide and kidney function: a systemic review and meta-analysis. Adv. Nutr. 2021;12:1286 – 1304.
  • Zhou J, Wang, D, Li B, et al. Relationship between plasma trimethylamine N-oxide levels and renal dysfunction in patients with hypertension. Kidney Blood Press Res. 2021;46:421-432.
  • Benson TW, Conrad KA, Li XS, et al. Gut Microbiota–Derived Trimethylamine N-Oxide Contributes to Abdominal Aortic Aneurysm Through Inflammatory and Apoptotic Mechanisms. Circulation. 2023;147(14):1079-1096
  • Wang M, Li XS, Wang Z, et al. Trimethylamine N-oxide is associated with long-term mortality risk: the multi-ethnic study of atherosclerosis. Eur Heart J. 2023 May 7;44(18):1608-1618.
  • Andrikopoulos P, Aron-Wisnewsky J, Chakaroun R, et al. Evidence of a causal and modifiable relationship between kidney function and circulating trimethylamine N-oxide. Nat Commun. 2023 Sep 20;14(1):5843.


Evidence of a causal and modifiable relationship between kidney function and circulating trimethylamine N-oxide

Nature Communications

September 2023

Gut Microbiota–Derived Trimethylamine N-Oxide Contributes to Abdominal Aortic Aneurysm Through Inflammatory and Apoptotic Mechanisms


April 2023

Trimethylamine N-oxide is associated with long-term mortality risk: the multi-ethnic study of atherosclerosis

European Heart Journal

March 2023

Relationship between Plasma Trimethylamine N-Oxide Levels and Renal Dysfunction in Patients with Hypertension


July 2021

Gut Microbiota-Derived Trimethylamine N-Oxide and Kidney Function: A Systematic Review and Meta-Analysis

American Society for Nutrition

May 2021

Gut microbe-targeted choline trimethylamine lyase inhibition improves obesity via rewiring of host circadian rhythms


October 2020

Evidence that TMAO Pathway Drives CKD in Humans



Rhee et al. J Am Soc Nephrol. 2013

The Framingham Heart Study identified elevated TMAO in a non-CKD cohort as an increased risk factor for incident CKD

Stubbs et al. J Am Soc Nephrol. 2016

Serum TMAO is inversely correlated with eGFR and is an independent risk factor for coronary atherosclerosis burden and mortality in CKD patients

Missailidis et al. PLoS One. 2016

Elevated TMAO is associated with increased inflammation and increased risk for all-cause mortality in CKD patients

Kim et al. Kidney Int. 2016

High baseline TMAO (>20 mM) is independently associated with CV events

Zhou et al. Kidney Blood Press Res. 2021

Elevated TMAO is associated with severe renal dysfunction and is predictive of early kidney disease in hypertensive patients

Tang et al. Circ Res. 2015

TMAO levels were markedly higher in CKD vs non-CKD patients; within CKD, TMAO in the highest quartile was independently associated with an increased mortality risk