IONS Up on FDA's Breakthrough Tag for ION582 in Angelman Syndrome

Ionis Pharmaceuticals IONS announced that the FDA has granted the Breakthrough Therapy designation to its pipeline candidate, ION582, for the treatment of Angelman syndrome (AS), a rare neurological disease.

Shares of Ionis were up 5.6% yesterday, following the announcement of the news.

AS is a rare neurogenetic disorder that impacts around 1 in 21,000 people globally. The disease often presents in infancy, which leads to severe developmental challenges, including cognitive and motor impairments, speech loss, balance issues, seizures, anxiety and sleep disturbances, taking a severe toll on the quality of life. Currently, no disease-modifying therapies are approved for treating AS.

Year to date, shares of Ionis have surged 84.2% compared with the industry’s rise of 12.5%.

How Does the FDA's Breakthrough Tag Benefit Ionis?

The FDA’s Breakthrough Therapy designation speeds up the development and review of drugs for serious or life-threatening conditions. This designation is granted when early clinical evidence suggests the drug may significantly improve over existing treatments on one or more important clinical measures. Drug/candidates with this designation receive more intensive guidance and organizational support from the FDA authorities.

The FDA’s Breakthrough Therapy tag to ION582 was based on data from the phase I/II HALOS study, which evaluated ION582 for treating AS. Data from the same showed that treatment with ION582 led to consistent and encouraging clinical improvement across all AS functional domains, including communication, cognition and motor function, while demonstrating a favorable safety and tolerability.

Earlier this year, Ionis initiated the phase III REVEAL study evaluating ION582 for treating children and adults with AS.

The FDA previously granted an Orphan Drug designation, Fast Track designation and Rare Pediatric designations to ION582 for treating AS.

Ultragenyx Pharmaceuticals RARE is also developing its pipeline candidate, GTX-102 (apazunersen), to treat AS.

In June, the FDA granted a Breakthrough Therapy designation to RARE’s GTX-102 for treating AS. Ultragenyx has completed enrollment and is currently dosing patients in the phase III Aspire study evaluating GTX-102 for treating patients with AS.

With both ION582 and GTX-102 in phase III development for AS, it remains to be seen which will succeed in gaining the first FDA approval for this rare disorder.

Ionis Pharmaceuticals, Inc. Price

Ionis Pharmaceuticals, Inc. price | Ionis Pharmaceuticals, Inc. Quote

IONS' Zacks Rank & Stocks to Consider

Ionis currently has a Zacks Rank #3 (Hold). Some better-ranked stocks in the biotech sector are Akero Therapeutics AKRO and Adaptive Biotechnologies ADPT, each carrying a Zacks Rank #2 (Buy) at present. You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.

In the past 60 days, estimates for Akero Therapeutics’ 2025 loss per share have narrowed from $3.93 to $3.82. Loss per share estimates for 2026 have narrowed from $4.27 to $4.12 during the same period. AKRO stock has surged 60.4% year to date.

Akero Therapeutics’ earnings beat estimates in three of the trailing four quarters while missing the same on the remaining occasion, the average surprise being 49.24%.

In the past 60 days, estimates for Adaptive Biotechnologies’ 2025 loss per share have narrowed from 87 cents to 71 cents. Loss per share estimates for 2026 have narrowed from 65 cents to 60 cents during the same period. ADPT stock has soared 110.3% year to date.

Adaptive Biotechnologies’ earnings beat estimates in each of the trailing four quarters, the average surprise being 23.99%.

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This article originally published on Zacks Investment Research (zacks.com).

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