Taysha Gene Therapies Raises $150M for Its Rare Disease Drug Pipeline

Led by new investor RA Capital Management, the new funding is expected to extend Taysha's cash runway into the third quarter of 2025, and aid in its development of a gene therapy treatment targeting Rett Syndrome, a neurological disorder that occurs primarily in girls.

Dallas-based clinical-stage gene therapy company Taysha Gene Therapies has received private placement financing of roughly $150 million to support the development of gene therapies for the treatment of rare neurological diseases, including Rett syndrome.

Taysha uses machine learning to develop gene therapies for diseases of the central nervous system.

Sean Nolan

The company said the securities purchase agreement is expected to extend its cash runway into the third quarter of 2025.

The funding was led by new investor RA Capital Management, with participation from a large institutional investor, PBM Capital, RTW Investments LP, Venrock Healthcare Capital Partners, TCGX, Acuta Capital Partners, Kynam Capital Management LP, Octagon Capital, Invus, GordonMD Global Investments LP, and B Group Capital.

“We’re pleased by the support from this prestigious group of new and existing investors, which we believe highlights the enthusiasm of the early clinical readout of the first patient treated in our REVEAL trial and reinforces the potential of gene therapy to transform the lives of patients suffering from devastating diseases,” Taysha Chairman and CEO Sean Nolan said in a statement.

Nolan replaced Taysha’s founder, RA Session II, as CEO in December.

Nolan said the company expects the funding will primarily support the clinical development of TSHA-102 in Rett syndrome and provide support for TSHA-102 program activities.

Rett syndrome occurs primarily in girls

A rare genetic neurological disorder that occurs primarily in girls, Rett syndrome leads to severe impairments. Rett affects speech, purposeful hand use, and coordination, leaving individuals understanding more than they can communicate. Caused by a gene mutation, Rett is first recognized in infancy.

A growing number of males with Rett are now being identified, however.

“With this capital infusion, we believe we are well positioned to continue to execute across key program milestones,” Nolan said.

Taysha also reported encouraging treatment results from dosing its first adult Rett syndrome patient.

Taysha’s principal investigator Elsa Rossignol reported that the patient was able to “sit unassisted for the first time in over a decade, and she demonstrated the ability to unclasp her hands and hold an object steadily for the first time since infancy.”

Taysha said that before treatment with its TSHA-102 drug, the patient had limited body movement, required constant back support, and lost her motor function early in childhood.

Jefferies is acting as exclusive placement agent in the private placement, Taysha said.

Get on the list.
Dallas Innovates, every day.

Sign up to keep your eye on what’s new and next in Dallas-Fort Worth, every day.

One quick signup, and you’re done.  

R E A D   N E X T

  • Dallas-based Taysha Gene Therapies is starting a new chapter in its fight to tackle devastating neurological conditions with changes in its top executive leadership. Late Friday, the publicly traded biotech announced that Sean P. Nolan, the current chair of the board of directors and an experienced biopharmaceutical industry leader, is the company's new CEO. Nolan succeeds RA Session II, who has resigned from the post. Session will continue to serve on the company's board of directors, Taysha said in a news release. In addition, Sukumar (Suku) Nagendran M.D., a seasoned physician, pharmaceutical developer, and biotech executive was named president and…

  • R.A. Session II, president, CEO, and founder of Taysha Gene Therapies [Background image: Olena Yepifanova via iStock]

    The investment by Tokyo-based Astellas Pharma gives it a 15% stake in Taysha and positions it to potentially purchase the company, according to the Dallas Morning News. The Dallas-based biotech firm's pipeline includes the "first-and-only" gene therapy in clinical development for Rett syndrome and a Phase 1/2 development of a treatment for an inherited nervous system disorder that's awaiting regulatory feedback. “We believe this investment not only further validates the potential of our technology platform, but also reinforces the therapeutic and market opportunity of our two lead clinical assets,” Founder and CEO R.A. Sessions II says. 

  • "There are over 10,000 rare diseases that affect millions of people worldwide, and most of them are genetic," notes UT Southwestern's Steven Gray (above, with Susan Iannaccone, M.D.). Testing on a total of eight genetic diseases has been approved for funding by the Bespoke Gene Therapy Consortium and other organizations.

  • UT Southwestern researchers have used gene editing technology to develop what could be a breakthrough for dilated cardiomyopathy, a heart condition that affects one in 250 people worldwide. “The pace of this field is really breathtaking,” said Eric Olson, Ph.D., who co-led the study. “I expect that if this moves forward into patients, we’re not talking within decades—we’re talking within years.”​ 

  • A subsidiary of Boston-based Bain Capital Credit is backing the launch of Legacy Corporate Lending, a new asset-based lending company headquartered in Plano that will serve middle market companies that might not be able to readily access traditional forms of lending. “We are excited to establish this well-capitalized platform in partnership with Bain Capital Credit at a time when lending provides an essential solution to many companies,” Legacy Corporate Lending CEO Clark Griffith said in a statement. “We see a significant opportunity to leverage our combined credit investment and industry expertise to provide borrowers with flexible, solutions-oriented capital. We look…