Shares of the international gene therapy developer uniQure (QURE -1.30%) have been soaring. Investors are responding to positive news regarding the Food and Drug Administration (FDA) and the company's Huntington's disease candidate.

During the first 12 days of December, shares of uniQure rocketed 152% higher, and investors want to know if this stock has legs that can propel it further in 2025. Let's weigh the positive news that drove the stock through the roof against some challenges the drugmaker faces to see if it's a smart stock to buy now.

Why uniQure stock is soaring

Shares of uniQure surged on Dec. 10 after the company gave investors great news regarding AMT-130, an experimental gene therapy it's developing to treat Huntington's disease. According to uniQure, the agency is willing to review an application for accelerated approval based on an ongoing pair of phase 1/2 clinical trials.

An accelerated approval based on ongoing studies could be a big deal because Huntington's disease progresses slowly. The clinical trials the FDA said it would consider began way back in 2019 and aren't expected to finish until 2029.

Reasons to remain cautious

The FDA has not yet started reviewing an application for the accelerated approval of AMT-130. The agency is expected to hold another meeting with uniQure in the first half of 2025 where it will, hopefully, outline a path forward.

Before getting too confident about a green light from the FDA, it's important to remember the pair of phase 1/2 trials included a control group that was given a sham procedure instead of AMT-130 injections. The control group was allowed to cross over and receive AMT-130 after 12 months, and several did. Unfortunately, 12 months isn't enough time for most early-stage Huntington's disease patients to present measurably worsening symptoms.

UniQure says the agency is willing to compare data from the phase 1/2 studies against long-term natural history external controls. The agency might be willing to consider an external control group. Everyone involved would much rather see a significant improvement versus the originally intended control group.

I wouldn't expect an already successful developer of gene therapies like uniQure to misrepresent FDA communications. In situations like this, though, it's important to understand the agency could have insisted on a new phase 3 trial as Wall Street had been expecting. Communications with the FDA are a private matter, and the agency as a rule never comments publicly on the accuracy of a drug developer's press releases.

Gene therapies are hard to sell, as uniQure investors learned with its first approved therapy, Hemgenix. The FDA approved Hemgenix for the treatment of hemophilia B in 2022, and it carries a list price of about $3.5 million. Unfortunately, uniQure's marketing partner CSL Behring isn't selling much of the treatment. In the third quarter, uniQure reported license revenues that reached just $2.3 million.

AMT-130 is a once-and-done gene therapy, which means you can't turn it off if it leads to unintended side effects. Wave Life Sciences is developing an RNA-based therapy with regular dosing that the Huntington's community could end up preferring.

Time to buy?

Huntington's disease is an inherited disorder that affects around 70,000 people in the U.S. and Europe. That's more than twice as prevalent as hemophilia B, plus Huntington's disease patients have fewer treatment options. There are still no approved drugs that slow the progression of the disease.

This summer, we learned that treatment with AMT-130 significantly lowered the amount of harmful protein fragments in circulation that indicate brain injury. It also slowed disease progression by 80% versus external controls, according to disease severity test scores.

With such strong evidence of a meaningful benefit, there's a pretty good chance this drug will earn FDA approval in 2026. Independent drug launches are unpredictable, but AMT-130 has a much better chance in the underserved Huntington's disease indication than Hemegenix did with the relatively well-served hemophilia B population.

Sales estimates for AMT-130 suggest more than $1 billion annually at its peak. The company probably won't have to ask for more capital for at least a couple of years. It finished September with $435 million in cash after burning through $44.4 million in the third quarter.

At the moment, uniQure sports an extremely modest $734 million market cap that could increase more than tenfold if AMT-130 earns FDA approval and goes on to generate more than $1 billion in annual sales. Buying this stock now to hold at least a few years could be a smart bet, but only for folks with an extremely high risk tolerance.