Astellas Pays $50M for Access to Taysha's Rett, GAN Programs

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Dallas-based Taysha Gene Therapies has entered into a strategic equity investment and licensing deal with Astellas. The Tokyo-baesd pharma stands to gain access to Taysha’s gene therapy development programs for Rett syndrome and GAN.

The pact supports “our strategy to accelerate the development timelines and increase the probability of success across our pipeline,” said R.A. Session II, Taysha’s founder, president and CEO, during a call with reporters.

Under the terms of the arrangement, Astellas is investing $50 million to acquire 15% of Taysha’s outstanding common stock. Astellas also picks up an exclusive option to license two of Taysha’s clinical-stage gene therapy programs, TSHA-102 for Rett syndrome and TSHA-120 for GAN.

Rett syndrome is a severe genetic neurodevelopmental disorder caused by a mutation in the MECP2 gene, which is needed for neuronal and synaptic function in the brain. It occurs mostly in women and is one of the most common genetic diseases causing severe intellectual disability, globally.

GAN (giant axonal neuropathy) is a rare inherited genetic disorder that affects the central and peripheral nervous systems. It is the result of loss-of-function mutations in the gene coding for gigaxonin, resulting in dysregulation of intermediate filament turnover, a vital structural component of the cell.

“Astellas will also receive one board observer seat on the Taysha Board of Directors, which allows strategic alignment with Astellas and enables Taysha to leverage Astellas’ gene therapy expertise and manufacturing capabilities,” Session said.

"The next six to 12 months are going to be a busy time for Taysha,” said Kamran Alam, the company's CFO.

In December 2022, Taysha is holding a post-Phase II Type B meeting with the FDA and expects minutes and feedback from that meeting in January.

In the first half of 2023, Taysha expects to report preliminary data on the clinical study of TSHA-102 in Rett. It also plans to initiate a female pediatric study in Rett syndrome during the same time period. 

Alam said that although Astellas could trigger its licensing options immediately, it is more likely to be “tied to two key events” — the results of the FDA Type B meeting and the preliminary data readout.

Citing Astellas’ creativity in negotiating the terms of the deal, Alam said the “economics are negotiated at the time of the opt-in” … which provides “nice ways to model that…. Their flexibility on this for us was one of the key aspects of this deal.”

The primary use of the $50 million will be geared toward clinical operations of the two programs.

The company expects the funding will provide cash runway into the fourth quarter of 2023.

Session said the deal builds upon Astella’s acquisition of Audentes.

Astellas acquired San Francisco-based Audentes Therapeutics in December 2019 for a total equity value of about $3 billion. The acquisition added an additional Primary Focus Area, Genetic Regulation, to Astella’s three primary areas: Blindness & Regeneration; Mitochondria Biology; and Immuno-Oncology.

In June 2022, Astellas opened its Gene Therapy Manufacturing Facility in North Carolina.

“We run very similar manufacturing platforms,” Alam said. "It’s a very similar manufacturing process that I think we will be able to utilize quickly.”

Naoki Okamura, Astellas’ chief strategy officer said gene therapy is the cornerstone of Astellas' primary focus - genetic regulation.