MIRM Enrolls First Patient in Phase II Fragile X Syndrome Study

Mirum Pharmaceuticals MIRM announced that it has enrolled the first patient in the phase II BLOOM study evaluating its newly in-licensed PDE4D inhibitor, MRM-3379, for treating Fragile X syndrome (FXS).

The BLOOM study will evaluate the safety, tolerability and potential clinical benefit of MRM-3379 in male participants with a confirmed genetic diagnosis of FXS, a rare genetic neurocognitive disorder.

Currently, there are no approved therapies for the given indication.

The primary endpoint of the BLOOM study is safety and tolerability. Top-line data from the same is expected in 2027.

FXS is caused by a mutation in the FMR1 gene, which is the most common inherited form of intellectual disability and autism. This neurocognitive condition affects around 50,000 males in the United States and Europe.

Last October, Mirum in-licensed worldwide rights to develop and commercialize MRM-3379 from Enthorin Therapeutics and Dart Neuroscience.

Per the company, MRM-3379 has shown improvements across several cognitive and behavioral symptoms linked to FXS, and a favorable tolerability in healthy volunteers in preclinical studies. If successfully developed, MRM-3379 may offer a novel approach to improving cognition and daily function for patients living with FXS.

MIRM’s Price Performance

Year to date, shares of Mirum have rallied 69.3% compared with the industry’s rise of 20.3%.

MIRM’s Marketed Drugs Aid Growth & Other Pipeline

Mirum’s lead product, Livmarli (maralixibat), an orally administered ileal bile acid transporter (“IBAT”) inhibitor, is approved for the treatment of cholestatic pruritus in patients with Alagille syndrome (“ALGS”) worldwide. The drug is also approved for treating certain patients with progressive familial intrahepatic cholestasis (“PFIC”) in the United States and Europe.

The FDA has also approved a new tablet formulation of Livmarli for treating cholestatic pruritus in patients with ALGS and PFIC. The oral tablet is likely to offer convenience for older patients.

In the first nine months of 2025, Livmarli’s net product sales were $253.6 million, up 70% year over year. The drug has been driving the majority of the company’s revenues.

Besides Livmarli, Mirum is also making good progress with Cholbam capsules and Ctexli tablets, which are approved for certain rare diseases. Sales of the bile acid products also increased during the first nine months of 2025.

Meanwhile, Mirum’s lead pipeline candidate, volixibat, is currently being evaluated in two phase IIb studies for treating patients with primary biliary cholangitis (the VANTAGE study) and primary sclerosing cholangitis (the VISTAS study).

Enrollment in the VISTAS study was completed in September 2025, with top-line data expected to be announced in the second quarter of 2026. The company expects to complete enrollment in the VANTAGE study in 2026.

MIRM's Zacks Rank & Stocks to Consider

Mirum currently carries a Zacks Rank #3 (Hold).

Some better-ranked stocks in the biotech sector are CorMedix CRMD, Arcutis Biotherapeutics ARQT and ADMA Biologics ADMA. While CRMD currently sports a Zacks Rank #1 (Strong Buy), ARQT and ADMA carry a Zacks Rank #2 (Buy) each, at present. You can see the complete list of today’s Zacks #1 Rank stocks here.

In the past 60 days, estimates for CorMedix’s 2025 earnings per share (EPS) have increased from $1.83 to $2.87. EPS estimates for 2026 have moved up from $2.48 to $2.88 during the same period. CRMD stock has surged 20.8% year to date.

CorMedix’s earnings beat estimates in each of the trailing four quarters, with an average surprise of 27.04%.

In the past 60 days, estimates for Arcutis Biotherapeutics’ loss per share have narrowed from 44 cents to 24 cents for 2025. During the same time, EPS estimates for 2026 have increased from 9 cents to 41 cents. Year to date, shares of ARQT have rallied 118%.

Arcutis Biotherapeutics’ earnings beat estimates in each of the trailing four quarters, the average surprise being 64.80%.

In the past 60 days, estimates for ADMA Biologics’ EPS have increased from 57 cents to 58 cents for 2025. During the same time, EPS estimates for 2026 have improved from 88 cents to 90 cents. Year to date, shares of ADMA have gained 13%.

ADMA Biologics’ earnings beat estimates in one of the trailing four quarters, matched once and missed the same on the remaining two occasions, with the average negative surprise being 3.01%.

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