For a healthier world

What does Quercis Pharma do?

Quercis is studying the use of its novel, proprietary and orally available anti-thrombotic, anti-cancer, antiviral and immuno-modulatory platforms to deliver innovative, effective, safe and broadly accessible treatments to patients with potentially life-threatening conditions addressing significant unmet medical needs.

With its portfolio of PDI inhibitors and Mast Cell Activation Modulators– – Quercis Pharma is committed to develop next-generation anti-thrombotics that turn off the blood clotting mechanism instead of thinning the blood without increasing the risk of bruising and bleeding while addressing VTE in cancer and eventually their use to prevent thrombosis in high-risk Sickle-Cell Disease, Cardiac and Stroke patients.

Strong initial data has indicated potential anti-neoplastic effects of our PDI inhibitors. We are committed to understanding the contribution of PDI to cancer tumorigenesis and cancer metastasis.

The relationship between viral illness and thrombosis and how PDI influences this as well as inflammasome behavior in the presence of our drug candidates gives us real hope for future thrombosis prevention and treatment in cancer, viral illnesses and other diseases.

Quercis has a preliminary program in ALS where a combination of Zafirlukast and Kinisoquin™ is being tested.

Initial Focus

Our initial focus and lead indication is on prevention of venous thrombosis and pulmonary embolism in high-risk cancer patients with our drug candidate Kinisoquin™, containing our patented Isoquercetin formulation.

Secondary Focus

Our secondary focus is on prevention of thrombosis in steady state and crisis-prone sickle cell disease patients so addressing with an accessible medication the unmet medical need of millions of predominantly impoverished patients worldwide.


The safety of our investigational drug has been proven in various studies, with no serious side effects having been identified, in particular our drug candidate for cancer thrombosis and sickle cell disease has to date shown no increased bleeding risk in clinical trials conducted in collaboration with Harvard Medical School and the United States National Institutes of Health (NIH).


A clinical Phase 2 study in the United States has shown that Kinisoquin™ reduced hypercoagulability in cancer patients at high risk for thrombosis with an improved benefit/risk ratio. https://doi.org/10.1172/jci.insight.125851

A clinical Phase 2 study conducted by the NIH showed that Kinisoquin™ treatment attenuated blood coagulation, platelet aggregation and inducible tissue factor gene expression in adults with sickle cell disease. https://www.sciencedirect.com/science/article/pii/S2473952923006353

Unique pathway

Our unique pathway is based on a new mechanism of action that arrests and/or reverses platelet aggregation with a profile that conveys vastly lowered bleeding risk compared to current standard of care.


Quercis believes that drug development must be focused squarely on patient needs and that means ALL patient populations not just wealthy ones in first world countries. The humanitarian aspect of the Company is to look at treating global diseases in impoverished populations and to work with Governments and NGOs to improve healthcare in countries where they find it difficult to pay for development or production of new drugs to combat critical health threats such as Sickle Cell Disease. We plan to ensure that our next generation medications, available as capsules or tablets, drugs are made available to those less fortunate at massive discounts of 90% and more to less privileged communities around the world. Quercis plans to partner with Governments as well as NGOs to achieve this goal. Many wars are brought about by suffering of impoverished, less educated and oppressed populations who want to “break free” of an endless cycle of poverty, deplorable living conditions and lack of access to proper healthcare as a result of economic woes. Quercis is aware that it alone cannot solve all these complex problems, but we believe we can make a major contribution to health and peace by ensuring that the most vulnerable of human populations can access new orally available and affordable drugs.

Selection of Published Medical Articles

Kinisoquin™ (our Isoquercetin-based drug candidate) reduces coagulation markers in cancer patients at risk of thrombosis


Kinisoquin™ (our Isoquercetin-based drug candidate) reduces coagulation markers in sickle cell disease patients


Zafirlukast® (our repurposed drug candidate) has the potential to treat ovarian cancer. Thiol isomerase inhibition with zafirlukast represents a novel, well-tolerated therapeutic in the treatment of ovarian cancer.


Journal of Clinical Investigation

Kinisoquin™ (our Isoquercetin-based drug candidate) reduces coagulation markers in patients at risk of thrombosis

About us

Quercis Pharma AG is a privately owned, biopharmaceutical company based in Zug, Switzerland. Quercis Pharma is advancing a development pipeline of late-stage clinical studies that focus on the prevention of VTE in cancer patients and sickle cell disease. In addition, Quercis plans to target cancers and other diseases associated with thrombotic events. The Company’s lead drug candidate acts as an anti-thrombotic with significantly lower risk of thrombosis and resulting adverse events than existing treatments. The Company also has a combination drug for cancer and neurological indications in development.

Our Credo - Core Values