An Open Label Extension Study of CTI-1601 in Subjects With Friedreich's Ataxia

This is an open-label extension (OLE) study designed to evaluate the long-term safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and clinical effects of subcutaneous (SC) administration of CTI-1601, also known as nomlabofusp, in subjects with Friedreich's ataxia (FRDA).

The objectives of this OLE study are:

* To evaluate the safety of long-term subcutaneous (SC) administration of CTI-1601 in subjects with FRDA
* To evaluate the PK of long-term subcutaneous (SC) administration of CTI-1601 in subjects with FRDA
* To evaluate the effect of long-term subcutaneous (SC) administration of CTI-1601 in subjects with FRDA on:

  * Tissue FXN concentrations
  * Clinical evaluations of FRDA
  * Gene Expression and select lipids

This is an open label extension (OLE) study in patients with FRDA who participated in a prior clinical study of CTI-1601 to evaluate the safety, PK, PD, and clinical effects of long-term daily administration of CTI-1601.

Eligibility Criteria:
Inclusion Criteria:

* Subjects with FRDA who previously completed participation in a study of CTI-1601 will be eligible to participate in this study unless the subject experienced one or more of the following in a previous CTI-1601 study: a) serious adverse event (SAE) related to study drug; b) significant AE, defined as Grade 3 or higher according to the Common Terminology Criteria for Adverse Events (CTCAE), version 5.0 (or higher), related to study drug; c) some other event, related to participation in a previous study with CTI-1601, that supports the exclusion of the subject from participating in this study as determined by the Sponsor (i.e., an AE considered clinically significant by the Sponsor regardless of whether it met SAE criteria and regardless of CTCAE grade); d) Withdraw from participation in a previous study of CTI-1601 for any reason.
* Subject has a HbA1c less than or equal to 7.0%.
* Subject must demonstrate sufficient dexterity and visual acuity to prepare and self-administer SC injections of CTI-1601 QD or is able to identify a caregiver who will be trained and committed to prepare and administer the daily injections.

Exclusion Criteria:

Subjects are excluded from the study if any of the following exclusion criteria are met:

* Subjects who are confirmed as compound heterozygous (GAA repeat expansion on only one allele) for FRDA.
* Subject has any condition, disease, or situation, including a cardiac condition or disease, that in the opinion of the PI, could confound the results of the study or put the subject at undue risk, making participation inadvisable.
* Subject used any investigational drug (other than CTI-1601) or device within 90 days prior to Screening.
* Subject requires use of amiodarone.
* Subject used erythropoietin, etravirine, or gamma interferon within 90 days prior to Screening.
* Subject use of biotin supplementation that exceeds 30 mcg/day, either as part of a multivitamin or as a standalone supplement, within 7 days prior to the first dose of study drug. Biotin supplementation ≤30 mcg/day is permitted if taken at a stable dose and frequency for at least 28 days prior to Screening and there is a commitment from the subject to maintain the biotin dose throughout the study (due to interference with assays).
* Subject uses more than 3 grams of acetaminophen daily.
* Subject receives medication that requires SC injection in the abdomen or thigh.
* Subject is unable to discontinue medications that have not been at a stable dose and frequency for at least 28 days prior to Screening.
* Subject has a Screening echocardiogram (ECHO) LVEF \< 45%.
* Male subject has a QTcF \> 450 milliseconds or female subject has a QTcF \> 470 milliseconds on an ECG.