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Ichor Therapeutics, Inc.

Ichor Unveils Orally Bioavailable Antibody-like Scaffold in ACS Biochemistry

Published on 6 MAY 2018

LAFAYETTE, NY: This weekend, a landmark biotechnology was published for the first time in the peer-reviewed journal ACS Biochemistry. The article, “RPtag as an orally bioavailable, hyper stable epitope tag and generalizable protein binding scaffold,” describes a foundational technology that could have huge implications in drug discovery, diagnostics, and clinical antibody therapy.

“Development of the RPtag system, which was conducted entirely in-house from computer modelling through in vivo studies and without academic collaborators, is a true testament to the brilliance of Adam Blanden [Ichor CSO], leadership of Aaron Wolfe [Ichor COO], and dedication of our research team. The impact this technology has had on our own drug discovery efforts has been incredible. Its widespread deployment as a commercial product will have profound implications.”

– Kelsey Moody, CEO at Ichor Therapeutics, Inc.


Protein manufacturing is a massive technical hurdle that must be overcome for scientists to discover new drug candidates to treat disease. The 1st and 2nd generations of RPtag were the basis of a suite of protein chemistry tools that allow many hard or impossible-to-make proteins to be manufactured at scale for the first time.

Antoxerene, Inc., an Ichor portfolio company, has used the RPtag system for drug discovery. The company has identified new small molecule leads that target a major oncology pathway and a pathway implicated in the emerging field of age-associated senescence. The company is working to develop new classes of drugs based on these findings.

RecombiPure, Inc., also an Ichor portfolio company, plans to release the RPtag system as a product line to support life science researchers. The company will initially sell affinity chromatography kits, which aid in protein expression and purification. Additional kits to support other biochemistry techniques are scheduled for release, including ELISA, FRET, and IP-pull downs.

Senior biochemistry technician Ellie Lumen provides instruction on protein production using RPtag.


Antibodies are widely used in the life sciences because of their ability to bind targets of interest with high specificity. Many diagnostic tests rely upon antibodies for this reason. However, antibodies are fragile, and have a short shelf life that requires refrigeration. Cold-chain management of antibodies increases cost and severely limits access to diagnostic testing in the developing world.

The 3rd generation of RPtag features a programmable binding interface that, like antibodies, can be engineered to bind targets of interest with high specificity. Unlike antibodies, the RPtag platform is incredibly stable in harsh environmental conditions and can even survive repeat boiling. This 3rd generation of RPtag is being developed by Ichor into rugged diagnostic kits that can be deployed to meet the needs of humanitarian efforts in developing countries where cold supply chain is not accessible.

RPtag is in development for drug discovery, diagnostics, and clinical use.


In addition to diagnostic tests, the high specificity of antibodies also makes them useful in clinical applications. There are over 70 approved antibody therapies, which treat diseases from cancer and rheumatoid arthritis, to age-related macular degeneration and asthma, and beyond. The widespread use of clinical antibodies has led to the development of over a dozen competing scaffolds, several of which are now in clinical trials.

A limitation of these therapies is that they cannot survive the gastrointestinal tract like small molecule drugs and must therefore be administered by injection or infusion.

RPtag survives the gastrointestinal tract and was engineered to be taken up and delivered into the blood stream through the vitamin B12/intrinsic factor pathway. Further work to develop RPtag into a portfolio of therapeutic candidates by Ichor is ongoing.


All media inquiries should be directed to Stephanie Martens at info@ichortherapeutics.com.


This press release may contain certain forward-looking statements and information, as defined within the meaning of the Securities Act of 1933 and the Securities Exchange Act of 1934, and is subject to the Safe Harbor within such laws. This press release contains statements about expected future events that are forward-looking in nature and subject to risks and uncertainties.  Such forward-looking statements by definition involve risks, uncertainties and other factors, which may cause the actual results, performance or achievements of Ichor Therapeutics, Inc., Antoxerene, Inc., and RecombiPure, Inc. to be materially different from the statements made herein.