Relief Therapeutics Announces Final Readout of PKU GOLIKE^® Clinical Trial

Clinical Trial Demonstrates Superior Metabolic Control During Prolonged Fasting in PKU Patients

Results Expected to Promote Awareness and Adoption of PKU GOLIKE^®

GENEVA (DEC. 16, 2024) – RELIEF THERAPEUTICS Holding SA (SIX: RLF, OTCQB: RLFTF, RLFTY) (Relief, or the Company), a biopharmaceutical company committed to delivering innovative treatment options for select specialty, unmet and rare diseases, today announced the full readout and compelling results from the clinical trial evaluating PKU GOLIKE as a protein substitute for the treatment of phenylketonuria (PKU) in patients during prolonged fasting periods. The study demonstrated that PKU GOLIKE, administered as the last daily dose and compared to standard amino acid protein substitutes, improved metabolic control by reducing harmful phenylalanine (Phe) levels and increasing beneficial tyrosine (Tyr) levels, both essential for brain function and metabolic health.

PKU patients often experience significant fluctuations in blood Phe levels during prolonged fasting periods, particularly at night, when protein breakdown causes Phe concentrations to peak in the early morning. These fluctuations are associated with cognitive difficulties and overall health impacts, making nighttime metabolic control an important focus in PKU management.

The Company-sponsored, randomized, crossover, controlled clinical study was conducted by the Inherited Metabolic Disorders Unit at Birmingham Children’s Hospital, UK, on pediatric patients with classical PKU, the condition’s most severe form. The trial compared PKU GOLIKE to standard amino acid protein substitutes in managing metabolic parameters during overnight fasting, the longest fasting period within 24 hours.

At the end of the one-week treatment period, patients receiving PKU GOLIKE as the last daily protein substitute dose showed a statistically significant reduction in blood Phe levels compared to those receiving standard amino acid substitutes (P=0.0002) and a statistically significant increase in blood Tyr levels (P=0.0113). Compared to baseline levels measured prior to the start of treatment, the PKU GOLIKE group achieved an average 17.8% reduction in blood Phe levels (P=0.0484) and an average 33.8% increase in blood Tyr levels (P=0.0008) upon awakening after the overnight fasting period. In comparison, when treated with standard amino acid protein substitutes, the same patients experienced an average 27.6% increase in blood Phe levels (P=0.0063) and no significant improvement in blood Tyr levels. Blood sample analysis at three early morning time points across the two groups revealed no significant differences in peak Phe levels upon reawakening in either group.

Highlighting the clinical significance of the findings, Prof. Anita MacDonald, principal investigator and leading dietitian in inherited metabolic disorders at Birmingham Children’s Hospital, stated: “Giving one dose of PKU GOLIKE as the final daily dose of protein substitute resulted in consistently better metabolic control in our cohort of patients with PKU. They all had classical PKU and were a particularly challenging group to control.”

These results confirm that PKU GOLIKE’s prolonged-release profile provides superior metabolic control during extended fasting periods compared to standard amino acid protein substitutes. The Company expects these findings to support adoption of PKU GOLIKE among healthcare providers and within the PKU community.

The study findings will be presented in a poster titled A Prolonged-Release Formula Has a Positive Impact on Morning Phenylalanine and Tyrosine Fluctuations in Patients with Classical Phenylketonuria at the 2025 ACMG Annual Clinical Genetics Meeting, March 18-22, 2025, in Los Angeles.

For more information on this study (NCT05487378), please visit clinicaltrials.gov.

ABOUT PHENYLKETONURIA
Phenylketonuria (PKU) is a genetic disorder caused by a deficiency of the enzyme needed to break down phenylalanine (Phe), leading to a toxic buildup of Phe from the consumption of foods containing protein or aspartame. Individuals with PKU lack the ability to metabolize Phe, which is present in many foods. Without treatment, PKU can cause severe neurological and developmental issues. The standard treatment involves a lifelong phenylalanine-restricted diet supplemented with amino acid-based, phenylalanine-free medical foods to prevent protein deficiency and optimize metabolic control.

 ABOUT PKU GOLIKE^®
PKU GOLIKE products are Foods for Special Medical Purposes (FSMPs) for the dietary management of PKU in children and adults. Developed with Relief’s proprietary, patent-protected Physiomimic Technology™ drug delivery platform, PKU GOLIKE products are the first prolonged-release amino acid FSMPs, characterized by a special coating that ensures physiological absorption of the amino acids mirroring that of natural proteins, while also masking the unpleasant taste and odor typically associated with amino acids. PKU GOLIKE products are marketed in the U.S. by Eton Pharmaceuticals Inc. under an exclusive license and supply agreement with Relief, in key European markets by Relief, and in select countries worldwide through licensing and distribution partners.

ABOUT RELIEF
Relief is a commercial-stage biopharmaceutical company committed to advancing treatment paradigms and delivering improvements in efficacy, safety, and convenience to benefit the lives of patients living with select specialty and rare diseases. Relief’s portfolio offers a balanced mix of marketed, revenue-generating products, proprietary, globally patented TEHCLO™ and Physiomimic™ platform technologies and a targeted clinical development pipeline consisting of risk-mitigated assets focused in three core therapeutic areas: rare skin diseases, rare metabolic disorders, and rare respiratory diseases. In addition, Relief is commercializing several legacy products via licensing and distribution partners. Headquartered in Geneva, Relief is listed on the SIX Swiss Exchange under the symbol RLF and quoted in the U.S. on OTCQB under the symbols RLFTF and RLFTY. For more information, visit www.relieftherapeutics.com.

CONTACT:
RELIEF THERAPEUTICS Holding SA
Jeremy Meinen
Chief Financial Officer
contact@relieftherapeutics.com

DISCLAIMER
This press release contains forward-looking statements, which may be identified by words such as "believe," "assume," "expect," "intend," "may," "could," "will," or similar expressions. These statements are based on current plans and assumptions and are subject to risks and uncertainties that could cause actual results, financial condition, performance, or achievements to differ materially from those expressed or implied. Such factors include, but are not limited to, changes in economic conditions, market developments, regulatory changes, competitive dynamics, and other risks or changes in circumstances. This communication is provided as of the date hereof, and Relief undertakes no obligation to update any forward-looking statements contained herein as a result of new information, future events or otherwise.