San Lorenzo, California – TheNewswire - May 11, 2022 - GeneTether Therapeutics Inc. (“GeneTether” or the “Company”) (CSE:GTTX), an innovative genetic medicines company focused on creating best-in-class gene editing therapies based on its proprietary GeneTether™ platform, announces a new paper co-authored by R. Geoffrey Sargent, GeneTether CSO, and colleagues from The University of California, San Francisco, The University of Texas, Health Science Center at Houston (UTHealth Houston), Kumamoto University, University of Pavia, and University of Vermont College of Medicine.

The paper entitled “Seamless Gene Correction in the Human Cystic Fibrosis Transmembrane Conductance Regulator Locus by Vector Replacement and Vector Insertion Events,” published online in the peer-reviewed journal “Frontiers in Genome Editing,” describes novel homology directed recombination (“HDR”) products and the subsequent derivation of seamless gene correction of the W1282X CFTR mutation in human induced pluripotent stem cells. The corresponding senior author is R. Geoffrey Sargent, PhD, CSO at GeneTether; and the first, and co-corresponding, author is Shingo Suzuki, PhD, research instructor at The Brown Foundation Institute of Molecular Medicine in McGovern Medical School at UTHealth Houston.

The paper demonstrates a class of HDR products that appear to be often overlooked in experiments using the CRISPR/Cas9 nuclease. One of the goals of gene editing is to make “seamless” corrections of mutant genes to restore the normal or wild type DNA sequence without errors including undesired mutations or inadvertent DNA sequence changes. The most frequent approach for HDR gene corrections is to replace the target mutation with the normal DNA sequences, a process sometimes referred to as vector replacement events. The research in the paper demonstrates that for some DNA repair, templates used to replace target mutations results in the duplication of the target gene sequences. These are often referred to as vector insertion events which have the potential to allow creation of multiple cell lines, containing different DNA edits, starting from one parental cell line.

“If we go back to classic HDR gene editing, before CRISPR/Cas, Transcription Activator-Like Effector Nucleases (TALENs), and Zinc Finger Nucleases (ZFN), vector insertion events were well-known and shown to occur in organisms from yeast to human cell lines. Indeed, under certain circumstances, vector insertion events can occur more frequently than vector replacement events. In the paper, we show that vector insertion events frequently occur using CRISPR/Cas9 treated human-induced pluripotent stem cells. We have now observed these events in other human iPS cell lines and at other genes,” commented Dr. Sargent. “This expands the toolkit of ways to modify genes in cells to study disease and for developing new therapeutic approaches. I am excited to utilize these HDR vector insertion products in our GeneTether™ platform development.”

About GeneTether

Founded by EGB Ventures founder and managing partner, William J. Garner, M.D., and veteran gene editing researcher, R. Geoffrey Sargent, Ph.D., GeneTether is focused on developing its disruptive proprietary platform technology to significantly increase the efficiency of DNA insertion into the genome for gene correction and complementation strategies. The Company’s wholly-owned platform technology uses a proprietary method to “tether” donor DNA templates to the genome editing complex, making the template readily available for use during the genome editing repair stage. The Company is leveraging its platform technology to develop curative therapies for the treatment of rare genetic diseases. GeneTether’s proof of concept study demonstrated an approximately 7x higher gene editing efficiency as compared to the same gene editing payload without application of GeneTether’s technology.

For more information, visit www.genetether.com.

Contact:

Geoffrey Sargent, CSO

(833) 294-4363 ext. 3

geoff@genetether.com

Forward-Looking Disclaimer

This news release contains statements that constitute "forward-looking statements." Such forward looking statements involve known and unknown risks, uncertainties and other factors that may cause GeneTether’s actual results, performance or achievements, or developments in the industry to differ materially from the anticipated results, performance or achievements expressed or implied by such forward-looking statements. Forward looking statements are statements that are not historical facts and are generally, but not always, identified by the words "expects," "plans," "anticipates," "believes," "intends," "estimates," "projects," "potential" and similar expressions, or that events or conditions "will," "would," "may," "could" or "should" occur. Forward-looking statements in this news release include the expectation that the Company will utilize HDR vector insertion products in its GeneTether™ platform development and all other statements that are not statements of historical fact.

Although GeneTether believes the forward-looking information contained in this news release is reasonable based on information available on the date hereof, by their nature forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause our actual results, performance or achievements, or other future events, to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements.  By their nature, these statements involve a variety of assumptions, known and unknown risks and uncertainties and other factors, which may cause actual results, levels of activity and achievements to differ materially from those expressed or implied by such statements. Examples of such assumptions, risks and uncertainties include, without limitation, those set forth under the heading “Risk Factors” in the Company’s final prospectus dated March 21, 2022.

The forward-looking information contained in this news release represents the expectations of the Company as of the date of this news release and, accordingly, is subject to change after such date. Readers should not place undue importance on forward-looking information and should not rely upon this information as of any other date. While the Company may elect to, it does not undertake to update this information at any particular time except as required in accordance with applicable laws.

Neither the Canadian Securities Exchange nor its Regulation Service has approved nor disapproved the contents of this news release.