QURE Or RGNX: Which Gene Therapy Was FDA Chief Really Warning About In Rare Disease Remarks?

(MENAFN- AsiaNet News)

• FDA Commissioner Marty Makary flagged concerns around invasive gene therapies delivered via skull openings.
• Investors initially linked the remarks to uniQure's AMT-130, a Huntington's disease gene therapy.
• Regenxbio's RGX-121 has also faced pressure, including a recent Complete Response Letter and clinical holds.

Shares of UniQure, Inc. (QURE) tumbled to a five-month low on Thursday after remarks from U.S. Food and Drug Administration (FDA) Commissioner Marty Makary triggered fears that its Huntington's disease gene therapy could face fresh regulatory hurdles.

However, a growing debate among analysts suggests the comments may not have been aimed at UniQure at all, but rather at Regenxbio, whose own gene therapy program recently received a rejection from the FDA.

QURE stock slumped 31% on Thursday, while RGNX stock gained 2.6%.

FDA Chief Flags Invasive Gene Therapies

In a CNBC interview, Makary defended the FDA's increasingly cautious stance toward rare disease therapies. He referenced a treatment in which researchers drilled small openings into patients' skulls to deliver a therapy that ultimately failed to show benefit in a randomized trial and carried safety risks.

“I have a lot of sympathy for those patients. There's nothing out there to offer them, but we're not going to go ahead and approve something like that that has morbidity associated with it,” Makary said.

Although he did not name a company, investors quickly interpreted the comments as a reference to UniQure's AMT-130, an investigational gene therapy for Huntington's disease that is delivered directly into the brain through a neurosurgical procedure.

Analysts Split On Makary's Target

RBC Capital Markets said the comments appeared to be directed at UniQure's Huntington's program. The firm described the situation as“disappointing,” but reiterated its 'Outperform' rating and maintained a $45 price target, implying a 163% upside from the stock's current levels.

Stifel took a similar tone, saying the stock's decline was“understandable,” noting Makary appeared to reference AMT-130 as an example of a therapy the FDA has not supported.

However, not all analysts agreed. Leerink argued that the remarks were more likely directed at Regenxbio's RGX-121 gene therapy than at UniQure's program.

The firm noted Makary seemed to be referencing a therapy that had already undergone regulatory review and failed to demonstrate sufficient effectiveness, which aligns with RGX-121.

UniQure Faces FDA Approval Uncertainty

The latest pressure adds to a shifting regulatory path for AMT-130 in recent months. Last year, UniQure said feedback from the FDA suggested data from its Phase I/II studies may no longer be sufficient to support a biologics license application (BLA), marking a change from earlier guidance.

In December, final meeting minutes from a pre-BLA discussion confirmed the agency was unlikely to consider existing trial data as primary evidence for approval. The company said last month that it had scheduled a Type A meeting with the FDA to discuss the data package supporting a potential accelerated approval pathway.

The company said it expects to provide a regulatory update once it receives the official meeting minutes.

Separately, earlier this month, UniQure reported updated preliminary Phase I/IIa data for its Fabry disease gene therapy AMT-191, showing sustained increases in enzyme activity among treated patients. The therapy has received Orphan Drug and Fast Track designations.

Regenxbio's RGX-121 Also Under Scrutiny

Regenerxbio's gene therapy programs have also faced regulatory challenges. Last month, the FDA placed a clinical hold on RGX-111, an investigational gene therapy for Hurler syndrome, and RGX-121, a gene therapy for Hunter syndrome, following a preliminary analysis of a tumor case in a treated patient.

Earlier this month, the FDA issued a Complete Response Letter (CRL) for RGX-121, citing concerns including uncertainty around study population definition, external control comparability and use of a surrogate endpoint.

While H.C. Wainwright said the CRL was in line with expectations following the earlier clinical hold, Morgan Stanley said the decision cited insufficient evidence of effectiveness and highlighted uncertainty around the regulatory path forward.

FDA Opens Door For Tailored Gene Therapies

Makary's remarks also came shortly after the FDA issued draft guidance to accelerate approvals of highly individualized therapies targeting ultra-rare conditions. The proposed framework is intended to provide regulatory flexibility in situations where traditional randomized trials are not feasible due to very small patient populations.

The guidance focuses on therapies that directly address the underlying genetic or biological cause of disease, including genome-editing and RNA-based treatments. Under the framework, sponsors may rely on natural history data and mechanistic evidence, rather than large clinical trials, to support effectiveness and safety.

How Did Stocktwits Users React?

On Stocktwits, retail sentiment for QURE was 'extremely bullish' amid a 1,230% surge in 24-hour message volume, while sentiment for RGNX remained 'neutral' amid 'extremely low' volumes. 

QURE sentiment and message volume as of February 27 | Source: Stocktwits RGNX sentiment and message volume as of February 27 | Source: Stocktwits

One user said,“I saw the interview again. Makary is not talking about Qure. We do not even have a BLA with FDA yet. This is a miracle treatment for Huntington's disease. I am loading up in the morning.

Another user said,“If people thought it could be RGNX, you would think RGNX would be down.”

While QURE stock fell 28% year-to-date, RGNX stock has declined 39% over the same period.

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