A Phase 2, Single Center, Open-Label, Multiple Dose Escalation Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Daily Subcutaneously Administered ELX-02 in Patients With Nephropathic Cystinosis Bearing One or More CTNS Gene (Cystinosin) Nonsense Mutations

This is a Phase 2 open label study to evaluate the safety, tolerability, PK, and PD of multiple dose levels of SC administered ELX-02 in patients with cystinosis with nonsense mutation in at least one allele.

Six patients will be enrolled in the trial.

The study will comprise of the following periods for each patient:

• A screening period of up to 6 weeks
• A total treatment period of 4 weeks
• A safety follow-up period of 4 weeks after the last treatment

Each patient will receive three escalating doses as follows:

• Treatment period 1: ELX-02 0.5 mg/kg SC daily for 7 days (total dose not to exceed 3.5 mg/kg for this week; the daily dose will be individualized to achieve the target weekly exposure of about 47.5 µg*h/mL)
• Treatment period 2: ELX-02 1.0 mg/kg SC daily for 7 days (total dose not to exceed 7.0 mg/kg for this week; the daily dose will be individualized to achieve the target weekly exposure of about 95 µg*h/mL)
• Treatment period 3: ELX-02 2.0 mg/kg SC daily for 14 days (total dose not to exceed 14 mg/kg for these two weeks; the daily dose will be individualized to achieve the target weekly exposure of about 190 µg*h/mL)