Intellia Therapeutics Cleared to Resume Key Gene Therapy Trial

The U.S. Food and Drug Administration (FDA) has granted Intellia Therapeutics permission to restart a major Phase 3 clinical trial. This authorization allows the company to proceed with its MAGNITUDE-2 study, which is evaluating the gene therapy candidate nexiguran ziclumeran (nex-z) for patients with hereditary transthyretin amyloidosis with polyneuropathy (ATTRv-PN). The decision marks a significant advancement for the firm's CRISPR-based development pipeline, even as a related study remains on hold.

Following a clinical hold initiated in late October, the FDA officially lifted the restriction on January 27. Intellia can now resume patient recruitment and treatment administration in this late-stage trial, with plans to restart operations promptly.

The initial suspension was triggered by a serious adverse event involving liver toxicity that occurred in a separate but related study named MAGNITUDE. To address safety concerns and enable the continuation of the ATTRv-PN program, Intellia and the regulatory agency agreed on specific modifications to the trial protocol. Key changes include:

• Enhanced safety monitoring of liver function throughout the study period.
• An increase in the target enrollment from approximately 50 to about 60 participants.

These adjustments are designed to provide more rigorous oversight of the gene therapy's safety profile in this patient population and to strengthen the statistical robustness of the findings.

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Parallel Cardiac Study Remains on Clinical Hold

While the MAGNITUDE-2 trial moves forward, the FDA's clinical hold on the Phase 3 MAGNITUDE study remains in effect. That investigation is testing the same nex-z therapy for a different manifestation of the disease, transthyretin amyloidosis with cardiomyopathy (ATTR-CM), which primarily affects the heart.

Intellia states that discussions with the FDA regarding the path forward for the MAGNITUDE trial are ongoing. Whether and in what form that study may continue is contingent upon further alignment with the regulator. The recent clearance applies explicitly only to the MAGNITUDE-2 trial.

Strategic Implications for Intellia's Pipeline

The partial lifting of the clinical hold represents a crucial step forward for Intellia's CRISPR-focused therapeutic programs. It enables the progression of a core late-stage project for ATTRv-PN while the company and regulators continue to evaluate potential risks in the ATTR-CM program.

In parallel, another major milestone is on the horizon. Intellia anticipates reporting initial topline results from its separate Phase 3 HAELO study in the first half of 2026. That trial is evaluating a gene therapy for hereditary angioedema. The clinical data from both the MAGNITUDE-2 and HAELO studies are expected to be primary factors shaping the market's assessment of Intellia's clinical progress throughout the coming year.