Treating the "Untreatable": A New Frontier in Peptide Therapeutics and Imaging
EndoCyclic’s precision peptides target diseased cells from the inside out, enabling selective uptake, pH-sensitive activation, and direct engagement of intracellular targets. This novel approach opens the door to both non-invasive diagnostics and disease-modifying therapeutics for conditions long considered difficult or impossible to treat.
Over years of study, EndoCyclic researchers realized that among trillions of possible peptide sequences, one rare class could behave differently. Instead of merely binding broadly, these peptides are absorbed selectively by diseased tissue, and once inside, they directly bind intracellular targets to reshape their structure and suppress harmful signaling.
“Peptides and proteins are how the body communicates, how cells tell each other when to grow, repair, or clear abnormal tissue,” said Dr. Tanya Petrossian, CEO, founder, and inventor. “Our peptides are designed to mimic those natural maintenance signals. They are selectively absorbed by diseased cells, engage intracellular targets, and restore healthy signaling. Cells that depend on pathogenic cues quietly recede, not through destruction, but through correction. The breakthrough is precision without hormones or toxicity. We aim to end the era of blanket, cytotoxic compounds and usher in a new class of targeted, non-hormonal therapeutics.”
What makes cyclic peptides special
Cyclic peptides occupy a middle ground in therapeutic design. They are not as small as classical small molecules nor as bulky as antibodies. Their intermediate size allows them to access complex interfaces on intracellular proteins while retaining kinetic flexibility and manufacturability.
“Cyclic peptides are the Goldilocks modality, not too large, not too small,” said Dr. Petrossian. “They combine specificity, tunability, and cost efficiency in a way few other modalities can.”
Because EndoCyclic’s peptides do not rely on conjugates or carriers, they avoid many of the complications common in advanced biologics. Their structure is not a vehicle for delivery. The structure is the therapeutic.
How they work
EndoCyclic’s discovery was not accidental. The team identified a specific endocytic pathway that is exclusively active in diseased tissue. Peptides are designed to use that pathway for uptake, ensuring they are absorbed only where pathology is present.
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Once inside the cell, the peptides activate in response to local pH. That activation allows them to reach its target and modulate the disease process at the source.
“Healthy cells don’t absorb our peptides,” said Dr. Petrossian. “And without uptake, there is no activity. That’s why we’ve seen no systemic effects in toxicology studies, the peptide simply doesn’t act where it doesn’t belong.”
Tuned for purpose
EndoCyclic’s peptide platform allows for precise control over how long each peptide remains active. Diagnostic agents are designed to clear quickly after delivering their signal, while therapeutic peptides are optimized for longer residence in diseased tissue to sustain their effect.
“The same core chemistry can be used for two entirely different applications,” said Dr. Petrossian. “It’s just a matter of tuning how long it stays and what it’s meant to do.”
"We aim to end the era of blanket, cytotoxic compounds and usher in a new class of targeted, non-hormonal therapeutics."
Dr. Tanya Petrossian
CEO, Founder, and Inventor​
Programs in development
Guided by the same precision-based design that defines our platform, EndoCyclic is advancing a new generation of targeted peptide medicines that translate discovery into clinical impact.
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EndoCyclic is laser-focused on completely transforming the way endometriosis is diagnosed and treated through two groundbreaking innovations: FemLUNA is a revolutionary first-in-class imaging diagnostic peptide that, for the first time, enables precise visualization of all subtypes of active disease without surgery. ENDO-205 is a groundbreaking, non-hormonal therapeutic that eliminates lesions at their origin, allowing pain and inflammation to naturally subside as the disease resolves without the need for immune suppression.
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“These are not derivatives of something else,” said Dr. Petrossian. “They’re brand new. Built from scratch to do one job, and do it well.”
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Building on these breakthroughs, EndoCyclic is expanding its precision peptide platform into cancer, fibrotic, and other women’s health diseases. Together, these programs reflect a unified vision to redefine how diseases are detected and treated through precision-engineered, non-hormonal peptides that restore health from within.
A new approach to chronic disease
Every person carries cells that could one day become abnormal. Pre-endometriotic, pre-cancerous, pre-fibrotic. The difference is often whether the body notices, and clears them.
“Our peptides help restore that surveillance system,” said Dr. Petrossian. “They’re not forcing the body to do something unnatural. They’re helping it recognize what’s out of place and respond appropriately.”
“We’ve seen peptides do amazing things, drugs like Ozempic and Wegovy have transformed how we treat metabolic disease,” she added. “Now we’re using that same power to take on endometriosis.”