Taysha Gene Therapies: Rett Syndrome Data Makes This A Must Watch

Taysha Gene Therapies (NASDAQ:TSHA) has made great progress recently in advancing its gene therapy known as TSHA-102 for the treatment of patients with Rett Syndrome. Despite only having data from one patient so far, with a second expected to start dosing in Q3 of 2023, the data shown thus far is impressive. The biotech noted that it intends to provide quarterly updates for its clinical programs, thus data from the second patient recruited into this phase 1/2 REVEAL trial, could be released by Q4 of 2023. If the second patient achieves a similar or better outcome than the first patient, then it will be confirmation that TSHA-102 may be highly suitable to treat patients with Rett Syndrome.

Besides such a catalyst in the coming months, this biotech has another gene therapy candidate being advanced, which is TSHA-120. This other gene therapy candidate is being advanced for the treatment of patients with Giant Axonal Neuropathy [GAN]. Taysha is gearing up to meet with the FDA in Q3 of 2023, whereby it and the agency will discuss a potential regulatory pathway forward for the use of TSHA-120 for the treatment of patients with GAN. Should this meeting conclude in a successful manner, then the company may be given the green light to initiate a pivotal study for this program. This remains to be seen, but this is another catalyst for traders/investors to look forward to. Lastly, it was able to obtain a $150 million private placement financing to boost its cash on hand. It believes that with this recent financing transaction, that it would have enough cash on hand to fund its operations into Q3 of 2025.

TSHA-102 Achieves Huge Improvement In First Patient With Rett Syndrome

Taysha Gene Therapies is advancing the use of gene therapy candidate TSHA-102 for the treatment of patients with Rett Syndrome. Rett Syndrome is a rare genetic neurological disorder by which severe impairment occurs in every aspect of an affected person's life. It affects many functions of life such as: Speech, coordination, and motor movement. It occurs as a result of a gene mutation, which is first recognized in infancy. While this disorder primarily affects girls, it is also being identified in many males as well. Other problems associated with this disease are muscle movements and communication skills. The thing is that most babies with Rett Syndrome develop as expected in the first 6 months of their life, however, they then lose such skills previously learned. They lose the ability to be able to communicate properly, crawl, walk or use their hands as needed. It is expected that the Rett Syndrome market will hit $515.06 million by 2029. This is a pretty good market opportunity for any biotech that can capture this market. Thus far, the whole market lies at the foot of Acadia Pharmaceuticals (ACAD), which received FDA approval of its drug Daybue for the treatment of Rett Syndrome in adult and pediatric patients 2 years of age and older. One thing to note is that Daybue is the first and only drug approved for the treatment of this patient population. However, another biotech with potential to capture this Rett Syndrome indication might be Anavex Life Sciences (AVXL). That's because it is gearing up to report top-line data from its potentially pivotal Anavex2-73-RS-003 phase 2/3 EXCELLENCE pediatric clinical trial. Top-line results from this study are expected to be released in the 2nd half of 2023. If this study succeeds, then this might be another possible competitor that Taysha Gene Therapies may have to ultimately contend with.

The thing is that the positive results that Taysha Gene Therapies was able to release, came from the phase 1/2 REVEAL trial, which used gene therapy TSHA-102 for the treatment of 1 patient with Rett Syndrome. Despite this only being one patient, it was noted that they had achieved improvement in key efficacy measures. Such clinical efficacy measures where improvement was achieved is as follows:

• Rett Syndrome Behavior Questionnaire [4-weeks post treatment]
• Clinical Global Impression - Severity [CGI-S]
• Clinical Global Impression - Improvement [CGI-I]

It was also noted that TSHA-102 was well tolerated, with no treatment emergent serious adverse events at 6-weeks. All these efficacy measures are great, but what is really outstanding is what this patient was able to accomplish after being given this therapy. Before this therapy their motor function was gone in early childhood, needed help to sit in an upright position and other issues. Once this patient was given TSHA-102, they were able to achieve a multitude of functions, such as the following:

• Improved breathing patterns
• Motor skills
• Vocalization
• Being able to sit without help for first time in over a decade
• Holding an object in a steady manner

While this was only observed in one patient thus far, it may be possible to see such marked improvement in another patient.

One thing to note is that the advancement of TSHA-102 for the phase 1/2 REVEAL study is only being done in adult patients. That is, the company is already preparing to expand the use of this gene therapy for the pediatric patient population. It has already made a move to move into this specific pediatric patient population through several advancements in the recent year. It has already received clearance from the FDA to initiate TSHA-102 in pediatric patients with Rett Syndrome in the United States. Not only that, but it has also already submitted a Clinical Trial Authorization [CTA] to the MHRA for TSHA-102 for pediatric patients with Rett Syndrome. Thus, the potential here lies with the ability to eventually expand to the entire Rett Syndrome patient population and not just in adults.

Financials

According to the 10-Q SEC Filing, Taysha Gene Therapies had cash and cash equivalents of $45.1 million as of June 30, 2023. It was able to receive gross proceeds of $150 million from a Private Placement Financing [PIPE] from new and existing investors. With this newly obtained financing, plus the cash on hand it already had, it believes that it will have enough to fund its operations into Q3 of 2025. It should be good on cash for now, but I wouldn't preclude the possibility that it might have to raise additional cash later on. That's because it intends to release quarterly updates on clinical data. With the second patient dosed and data coming within the coming months, it's possible that this might cause the stock price to trade higher. This or any other positive catalyst might make management consider raising additional cash. Such a raise is not guaranteed to happen, but quite possible nonetheless.

Risks To Business

There are several risks that investors should be aware of before investing in Taysha Gene Therapies. The first risk to consider would be with respect to the ongoing phase 1/2 REVEAL study, which is using TSHA-102 for the treatment of adults with Rett Syndrome. That's because additional results from the second patient in the study are expected to be released at least by Q4 of 2023. Despite the first patient seeing improvement with multiple efficacy measures with TSHA-102 for Rett Syndrome, there is no guarantee that the second patient will achieve a similar or superior outcome. A second risk to consider would then be about the possible expansion opportunity with respect to the Rett Syndrome patient population.

The company has already taken steps to initiate a few early-stage studies using TSHA-102 in pediatric patients with this disorder. There is no assurance that clinical data generated in adults will then translate over to the pediatric patient population. A third and final risk would be with respect the upcoming FDA meeting in Q3 of 2023, which is slated to discuss the potential regulatory approval pathway of using TSHA-120 for the treatment of patients with GAN. Taysha believes that it has the potential to a regulatory pathway in advancing this candidate for this patient population. However, it won't truly know what the FDA wants until it meets with the agency during this quarter. A risk here would be that the FDA may require additional patients or a new study, before even considering allowing a pivotal one.

Conclusion

Taysha Gene Therapies has done well to advance the use of TSHA-102 for the treatment of adults with Rett Syndrome. However, further confirmation is truly needed before knowing whether or not there is a good chance for the company to eventually receive FDA approval for it. At least, the biotech has already thought about expanding the use of TSHA-102 for the pediatric patient populations, which will help it target a larger chunk of the Rett Syndrome market. This was done through the clearance of the Investigational New Drug [IND] application of TSHA-102 and submission of the Clinical Trial Application [CTA] to the United Kingdom [UK] Medicines and Healthcare products Regulatory Agency [MHRA] for TSHA-102 in pediatric patients with Rett Syndrome.

This article is published by Terry Chrisomalis, who runs the Biotech Analysis Central pharmaceutical service on Seeking Alpha Marketplace. If you like what you read here and would like to subscribe to, I'm currently offering a two-week free trial period for subscribers to take advantage of. My service offers a deep-dive analysis of many pharmaceutical companies. The Biotech Analysis Central SA marketplace is $49 per month, but for those who sign up for the yearly plan will be able to take advantage of a 33.50% discount price of $399 per year.