Partner Therapeutics Announces Partnership with SIRS Therapeutics and F4 Pharma to Explore Potential Uses for FX06 in Biodefense Applications

FX-06 is a synthetic peptide with a broad spectrum of potential applications associated with endothelial barrier integrity, blood vessel permeability and inflammation

Potential applications include COVID-19, pandemic, chemical, biological, radiological and nuclear threats

Lexington, MA – March 3, 2021 — Partner Therapeutics, Inc. (PTx), a commercial biotech company, announces a licensing and collaboration agreement with Munich-based SIRS Therapeutics and Vienna-based F4 Pharma to support the development of FX-06, a synthetic peptide that has a broad spectrum of potential indications. The partnership will focus on exploring potential collaborations with the U.S. Government to develop FX-06 as a medical countermeasure against high priority threats for which there are significant unmet needs.

SIRS and F4 Pharma are developing FX-06 in diseases associated with capillary leak with a current focus on treating patients with COVID-19. FX-06 is a fibrin-derived peptide (peptide Bβ 15–42) that binds to VE-Cadherin, thereby restoring the barrier function of the endothelium. Based upon its ability to restore barrier function, prevent vascular leak and leukocyte transmigration and reduce vasoconstriction, FX-06 is anticipated to mitigate the duration and severity of hemorrhage and accelerate recovery from barrier integrity loss resulting from pandemic and biological threats, such as COVID-19 and hemorrhagic fevers, as well as chemical agents and acute radiation exposure.

“We are excited to work with Partner Therapeutics, given their impressive track record in late stage development in the area of medical countermeasures for bio-threats and their industry experienced development team. In collaboration with Partners Therapeutics we are focused on exploring FX-06 in areas of high interest and medical need,” said Anne Burger, CEO of SIRS Therapeutics.
Petra Wülfroth, CSO and co-founder of F4 Pharma “The current SARS-CoV-2 pandemic has highlighted the public vulnerability caused by viruses, however, other biological or chemical threat agents can also evolve into a major public concern. FX-06 has a broad applicability in diseases and pathological conditions caused by systemic inflammation and increased permeability of the blood vessels.” She added, “we believe its mechanism of action makes it promising tool to protect people.”
“FX-06 has been shown to counteract vascular leak and its fatal consequences from a variety of causes including thrombin, oxygen radicals, bacteria and viruses. Efficacy has been demonstrated in animal models of septic shock, hemorrhagic shock, dengue shock syndrome, capillary leak, hemorrhagic fever, reperfusion injury, transplantation and acute lung injury”, said Debasish Roychowdhury, MD, Chief Technology Officer at Partner Therapeutics. “We look forward to the opportunity to further explore the utility of FX-06 as a solution to the high priority threats identified by the U.S. Government”.

“We look forward to the opportunity to work with our partners at SIRS and F4 Pharma to advance the development of FX06 as a potentially important treatment for COVID-19 as well as future pandemic threats and unmet needs for medical countermeasures,” said John McManus, Chief Business Officer at Partner Therapeutics. “We believe that FX-06’s activity in both animal and human models could make it a powerful potential tool for both known and unknown threats”.

PTx plans to accelerate the development of FX-06 as a state-of-the-art pharmaceutical prototype MCM for the treatment of multiple biothreats of interest to the US Government. PTx is currently conducting two clinical trials of Leukine®, an FDA-approved immune modulator, in patients with COVID-19 under a $35 million development contract with the Department of Defense Joint Program Executive Office – Chemical Biological Radiological Nuclear (JPEO-CBRN). Leukine was FDA-approved for the treatment of the hematological damage due to acute radiation exposure under an advanced development contract with the Biomedical Advanced Research and Development Authority (BARDA) and is held in the Strategic National Stockpile for use in this indication.

PTx is an integrated biotechnology company focused on the development and commercialization of late-stage therapeutics that improve health outcomes in the treatment of cancer and other serious diseases. The company believes in delivering products and supporting medical teams with the purpose of achieving superior outcomes for patients and their families. Visit

SIRS Therapeutics GmbH is a development stage biopharmaceutical company that develops FX06, a fibrin-derived peptide for the treatment of diseases related to capillary leakage e.g., ARDS in patients with underlying COVID-19 infection. The Company was founded with initial investments from Wellington Partners in 2020 and is located in Germany.

F4 Pharma is a privately owned Austrian biotechnology company focusing on the development of the platform molecule FX06 in several indications with high unmet medical need. It is the intention of F4 Pharma to provide a safe and efficacious therapy to patients and physicians in critical disease situations in intensive care.

The endothelium, i.e. the inner layer of the blood vessels, plays an important role in the homeostasis between the blood within the vessel and the surrounding tissue. In many pathological disease situations, this well-balanced equilibrium is disturbed causing an increased permeability of the blood vessel and allowing inflammatory cells to invade into the surrounding tissue. The synthetic peptide FX06 binds to the contact points between the cells, normalizes increased permeability and reduces the systemic inflammation of the endothelium.