RVL-001 enters early n-of-1 studies for Rett syndrome and Pitt-Hopkins syndrome

Unravel Biosciences has dosed the first participants in 2 early proof-of-concept studies evaluating RVL-001, a proprietary formulation of vorinostat, for Rett syndrome (RTT) and Pitt-Hopkins syndrome (PTHS), according to a company announcement. The studies are placebo-controlled n-of-1 trials being conducted in Medellin, Colombia, with target enrollment of 15 patients with RTT and 5 with PTHS; completion is anticipated in the first quarter of 2027.¹

The update is notable because treatment options remain limited in both disorders. Rett syndrome is a rare neurodevelopmental disorder most often caused by pathogenic variants in MECP2, while Pitt-Hopkins syndrome is associated with TCF4 haploinsufficiency and has no approved drug therapy.^2,3 In the company statement, Richard Novak, PhD, cofounder and chief executive officer of Unravel, said, “Dosing our first patients in our RVL-001 trials is an important milestone for our company and for Rett syndrome and Pitt Hopkins syndrome patients.”¹

According to the press release, the RTT and PTHS studies are registered as NCT07150013 and NCT07150026 and are being run at the Universidad de Antioquia’s Group for Clinical Trials of PECET, an INVIMA-designated clinical trial site. Unravel described both trials as placebo-controlled n-of-1 studies, but did not provide additional methodological details in the announcement, such as treatment period length, crossover structure, or prespecified primary end points.¹ That limits immediate interpretation of how signal detection will be handled in a very small and clinically heterogeneous population.

RVL-001 is a formulation of vorinostat, a histone deacetylase (HDAC) inhibitor already approved in the US for cutaneous manifestations of refractory, persistent, or progressive cutaneous T-cell lymphoma.⁴ The company said the agent is being tested against a “novel therapeutic mechanism” in RTT and PTHS, and that its BioNAV platform identified the drug as a candidate for both disorders.¹ From a clinical perspective, however, the key question will be whether epigenetic modulation with vorinostat can produce measurable improvements in neurologic or autonomic symptoms without unacceptable adverse effects in pediatric patients with severe neurodevelopmental disease.

That question arises in a treatment landscape that remains sparse. Trofinetide became the first FDA-approved treatment for RTT in 2023, based on phase 3 data showing improvement on co-primary end points that included caregiver- and clinician-rated measures, although diarrhea and vomiting were common adverse events.² Rett syndrome care otherwise remains largely supportive and multidisciplinary, addressing seizures, breathing abnormalities, scoliosis, nutrition, and communication needs. For PTHS, management is supportive, with no approved disease-directed pharmacotherapy.³

The rationale for studying vorinostat in RTT and PTHS is biologically plausible in broad terms, given the role of transcriptional dysregulation in both disorders. Still, plausibility does not establish clinical benefit, and HDAC inhibition carries known safety considerations, including gastrointestinal toxicity, fatigue, thrombocytopenia, and electrocardiographic abnormalities in oncology use.⁴ Whether a proprietary formulation and dosing strategy can make the risk-benefit profile acceptable in these populations remains to be determined.

In the company release, principal investigator Carolina Lesmes, MD, said the site had spent several months preparing for the studies and was ready to support trial progress.¹ For clinicians and families, the start of enrollment may be encouraging, but the present announcement marks a developmental milestone rather than an efficacy readout. No interim data were disclosed, and no claims can yet be made about clinical response.

The studies’ small planned enrollment and individualized design may be appropriate for signal-finding in ultra-rare disorders, but they also underscore the limitations ahead. Even if positive, n-of-1 data may be difficult to generalize across the phenotypic spectrum of RTT and PTHS. Further work would likely need to clarify optimal end points, duration of benefit, age-related response, and safety with repeated dosing before any broader regulatory path becomes clear.

References

1. Unravel Biosciences Announces First Patient Dosed in RVL-001 Proof of Concept Studies for Rett Syndrome and Pitt Hopkins Syndrome. BusinessWire. May 12, 2026. Accessed May 12, 2026. https://www.businesswire.com/news/home/20260512041694/en/Unravel-Biosciences-Announces-First-Patient-Dosed-in-RVL-001-Proof-of-Concept-Studies-for-Rett-Syndrome-and-Pitt-Hopkins-Syndrome

2. Neul JL, Percy AK, Benke TA, et al. Trofinetide for the treatment of Rett syndrome: a randomized phase 3 study. Nat Med. 2023;29(6):1468-1475. doi:10.1038/s41591-023-02398-1

3. Rosenfeld JA, Leppig K, Ballif BC, et al. Genotype-phenotype analysis of TCF4 mutations causing Pitt-Hopkins syndrome shows increased seizure activity with missense mutations. Genet Med. 2009;11(11):797-805. doi:10.1097/GIM.0b013e3181bd38a9

4. US Food and Drug Administration. Zolinza (vorinostat) prescribing information. Revised 2024. Accessed May 12, 2026. https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/021991s023lbl.pdf