The purpose of this study is to evaluate the safety and tolerability of DF-003 in retinal dystrophy, optic nerve edema, splenomegaly, anhidrosis, and migraine headache (ROSAH) syndrome patients.

This is a Phase Ib open-label, single-arm, single-dose study that will be conducted in up to 12 ROSAH syndrome patients. The study will investigate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of DF-003 (study drug). DF-003 will be administered orally (PO), once daily (QD) for 28 days (4 weeks). Patients will be followed up for 8 weeks after administration of the last dose of study drug.

A total of 8 patients will be evaluated in one cohort. The cohort will have a minimum of 6 patients. Additional patients (maximum of 12 patients) may be enrolled in the event of insufficient data after a review of safety data by the Study Safety Committee. Patients will receive loading doses of 140 mg DF-003 on Days 1, 2, and 3, followed by a maintenance dose of 45 mg DF-003 starting on Day 4 through Day 28. Individual dose modification is not allowed in this study.

Inclusion Criteria:

1. Sufficient understanding of the purpose and procedures required for the study.
2. Body mass index (BMI) of 18.0 to 35.0 kg/m2, inclusive.
3. Genetic testing for ALPK1 mutations that has been shown to be associated with ROSAH syndrome (e.g. T237M or Y254C, or T237A mutations).
4. Signs of uveitis (anterior and/or posterior) in the eye (e.g. macula edema, optic nerve edema, retinal vasculitis, or retinal vascular leakage).
5. Patients must be deemed healthy except for diagnosis of ROSAH syndrome and its clinical manifestation.
6. Patients must be at least 18 years of age but no older than 65 years of age at the time of Screening.

Exclusion Criteria:

1. Males who plan to father a child or donate sperm while enrolled in this study or within 90 days after the last dose of study drug.

2. Females who are pregnant, breastfeeding, planning to become pregnant, or planning to donate eggs while on study medication or within 90 days after the last dose of study drug.

3. Use of any of the following prohibited medications:

   • Agents that are known to have systemic anti-inflammatory responses or high risk for nephrotoxicity or hepatotoxicity
   • Moderate CYP3A4 inhibitors: e.g., amiodarone, amprenavir, conivaptan, delavirdine, diltiazem, erythromycin, fluconazole, fosamprenavir, imatinib, miconazole, verapamil, grapefruit juice, cat's claw (Dolichandra unguis-cati), Echinacea augustifolia, wild cherry, chamomile, licorice
   • Strong CYP3A4 inhibitors: e.g., ceritinib, clarithromycin, cobicistat, elvitegravir/ritonavir, idelalisib, indinavir/ritonavir, itraconazole, ketoconazole, lopinavir/ritonavir, nefazodone, nelfinavir, paritaprevir/ritonavir, ombitasvir/paritaprevir/ritonavir (and/or dasabuvir), posaconazole, ritonavir, saquinavir/ritonavir, telithromycin, tipranavir/ritonavir, voriconazole.
   • Strong CYP3A4 inducers: apalutamide, carbamazepine, enzalutamide, ivosidenib, lumacaftor/ivacaftor, mitotane, phenytoin, rifampin, St. John's wort.
   • Digoxin
   • Agents known to cause Torsade de Pointes: Disopyramide, procainamide, quinidine, sotalol, azithromycin, clarithromycin, erythromycin, ciprofloxacin, levofloxacin, moxifloxacin, fluconazole, ketoconazole, pentamidine, voriconazole, haloperidol, thioridazine, ziprasidone, citalopram, escitalopram, dolasetron, droperidol, granisetron, and ondansetron
   • Investigational agents (small molecules and oligonucleotides), vaccines, or invasive medical devices within 28 days (4 weeks, or 5 half-lives, whichever is longer) prior to enrollment or having received a biological product within 6 months prior to enrollment.

4. History of significant hypersensitivity to products related to DF-003 (including excipients of the formulations) as well as severe hypersensitivity reactions (like angioedema) to any drugs.

5. Recent (within 3 months prior to screening) or acute changes in the following laboratory values:

   • Platelet count ≤ 120,000/mm3, or
   • Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) > ULN
   • Bilirubin (total, direct) > ULN or
   • International Normalization Ratio (INR) > ULN, or
   • Serum albumin less than the lower limit of normal, or
   • Estimated creatinine clearance < 70 mL/min/1.73 m2 at Screening, calculated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula, or
   • Hemoglobin A1c (HbA1c) > 8%.

6. Moderate or severe hepatic impairment (categorized as Child-Pugh class B and C, respectively, on the Child-Pugh Score for Cirrhosis Mortality)

As this is an open label study, there are no blinding requirements for safety data.