Cycle Pharmaceuticals announced the launch of HARLIKU, the first and only FDA-approved treatment for reducing urinary homogentisic acid (HGA) in adult patients with alkaptonuria (AKU).¹

AKU, also known as Black Bone Disease, is an ultra-rare genetic metabolic disorder that affects approximately one in 1,000,000 people in the US.²

HARLIKU can reduce urinary HGA production by up to 97% through the inhibition of an upstream enzyme.¹ Clinical data demonstrated that nitisinone-treated patients experienced significant improvement in pain, energy levels, and physical functioning.³

With the launch of HARLIKU, patients now have the option of treatment, guidance and care tailored to the unique needs of AKU. Accompanied by our dedicated support program, Cycle Vita™, patients will receive individualized support* from onboarding to continuous product and clinical support throughout treatment.

“AKU is an ultra-rare condition with slow progression and variable presentation, which makes diagnosis and accessing appropriate care difficult.^{2, 4} With the launch of HARLIKU, Cycle Vita can now provide patients with AKU the individualized support they need to navigate their treatment from diagnosis onwards.” – Jamie Ray, Director – Patient Support Program, Cycle Pharmaceuticals

“The launch of HARLIKU marks an exciting milestone for our AKU community. As the first commercially available treatment for AKU in the United States, it will empower patients to take a more proactive role in their care, paving the way for personalized treatment discussions and helping to reduce barriers to access.” - Nick Sireau, CEO and Chair of Trustees, AKU Society

Indications

HARLIKU™ is indicated for the reduction of urine homogentisic acid (HGA) in adult patients with alkaptonuria (AKU).

Important Safety Information

Do not prescribe HARLIKU to patients allergic to nitisinone or any other contained ingredients.

Warnings and Precautions:

Ocular Symptoms and Hyperkeratotic Plaques Due to Elevated Plasma Tyrosine Level:

Ocular signs and symptoms including keratitis, corneal opacities, corneal irritation, corneal ulcers, conjunctivitis, eye pain, and photophobia, have been reported in patients.

• Perform slit-lamp examination prior to treatment and regularly thereafter. Reexamine patients if symptoms develop or tyrosine levels are > 500 micromole/L. Assess plasma tyrosine levels in patients with an abrupt change in neurological status.
• Perform a clinical laboratory assessment, including plasma tyrosine levels, in patients with an abrupt change in neurological status.

Leukopenia and Severe Thrombocytopenia

In clinical trials, patients with hereditary tyrosinemia type 1 (HT-1) treated with another oral formulation of nitisinone and dietary restriction developed reversible leukopenia (3%), thrombocytopenia (3%), or both (1.5%). No patients developed infections or bleeding as a result of the episodes of leukopenia and thrombocytopenia. Monitor platelet and white blood cell counts during HARLIKU therapy.

Adverse Reactions:

The most common adverse reactions (≥1%) reported in patients with AKU taking nitisinone in clinical trials are elevated tyrosine levels, thrombocytopenia and keratitis.

Drug Interactions:

• Nitisinone is a moderate CYP2C9 inhibitor and a weak CYP2E1 inducer. Potential clinical impact of Harliku administration with CYP2C9 substrates. Reduce the dosage of the co-administered drugs metabolized by CYP2C9 by half. Additional dosage adjustments may be needed.
• Nitisinone is an inhibitor of OAT1/OAT3. Potential clinical impact of administration with OAT1/OAT3 substrates. Patients should be monitored for potential adverse reactions.

Use in Specific Populations:

Pregnancy: Limited available data with nitisinone use in pregnant women are not sufficient to determine a drug-associated risk of adverse developmental outcomes. The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes.

Lactation: The developmental and health benefits of breastfeeding should be considered against the mother’s clinical need for HARLIKU, along with potential adverse effects on the breastfed infant from HARLIKU or from the underlying maternal condition.

Pediatric Use: The safety and effectiveness of HARLIKU have not been established in pediatric patients with AKU.

Geriatric Use: Insufficient data from clinical studies of HARLIKU to determine if patients ≥ 65 years of age respond differently. Elderly patients should be cautious reflecting any decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

For more detailed information, please refer to the full Prescribing Information at harliku.com/pi

To report SUSPECTED ADVERSE REACTIONS, contact Cycle Pharmaceuticals at

1-855-831-5413, or the FDA at: 1-800-FDA-1088 or www.fda.gov/medwatch.

US-HKU-2500015 | June 2025

References

1. HARLIKU (nitisinone) Tablets. Prescribing Information. Cycle Pharmaceuticals Ltd
2. Introne WJ, Perry M, Chen M. 2003 (updated 2021). Alkaptonuria. Available at: https://www.ncbi.nlm.nih.gov/sites/books/NBK1454/ [Accessed May 29 2025]
3. Spears KR, Rossignol F, Perry MB, et al. 2024 Patient-reported outcomes and functional assessments of patients with Alkaptonuria in a 3-year Nitisinone treatment trial. Mol Genet Metab. 143(1-2),108562. doi:10.1016/j.ymgme.2024.108562
4. Zatkova, A., Ranganath, L., & Kadasi, L. 2020. Alkaptonuria: Current Perspectives. The application of clinical genetics, 13, 37–47. doi:10.2147/TACG.S186773

*Some areas of support may not be accessible to all patients. Eligibility criteria may apply to ensure compliance with all applicable federal and state requirements, and benefits may be limited to commercially insured patients only. For more detailed information about eligibility, terms and conditions, please contact the Cycle Vita team at 888-360-8482.

©2025 Cycle Pharmaceuticals Limited. All rights reserved.

HARLIKU™ and Cycle Vita™ are trademarks of Cycle Pharmaceuticals Limited in the United States.

About Cycle Pharmaceuticals

Cycle Pharmaceuticals was founded in 2012 with the sole aim of delivering drug treatments and product support to the underserved rare disease patient community. Cycle Pharma focuses on rare genetic conditions in metabolic, immunology, urology, and oncology, as well as neurology, where we focus on multiple sclerosis. Cycle Pharma is headquartered in Cambridge, UK and has offices in Boston, Massachusetts. For more information, please visit www.cyclepharma.com and follow us on X, LinkedIn and Facebook.

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