CTI-1601 for FRDA On Hold After Monkey Study Deaths


Sometimes, medical studies just don’t go the way that companies want them to. According to MedCity News, this is what biotechnology company Larimar Therapeutics (“Larimar”) was faced with during a study of their experimental therapy CTI-1601. The therapy is designed for patients with Friedreich’s ataxia (FRDA). But following a number of monkey deaths in one study, the entire clinical development program is now on hold.


According to Larimar:

CTI-1601 is a recombinant fusion protein intended to deliver human frataxin into the mitochondria of patients with Friedreich’s ataxia. Based solely on the results of our nonclinical development program, we believe CTI-1601 is processed to mature frataxin [which patients with FRDA are unable to produce enough of] and becomes active in mitochondrial metabolism.

Thus far, CTI-1601 earned Orphan Drug, Fast Track, and Rare Pediatric Disease designations.

The Issue

In studies evaluating varying CTI-1601 doses, no issues were observed. However, the FDA stopped the entire clinical development program following a series of monkey deaths within an ongoing non-human primate toxicology study. Altogether, the nearly 6-month long study served to determine how extended CTI-1601 dosing would impact patients. During the trial, a number of monkeys died. These monkeys were receiving the highest dose of CTI-1601, according to Larimar. Now, the FDA has put the study on hold until the agency can read and analyze a study report. Additionally, Larimar is unable to participate in any other clinical studies during this time.

This presents a huge blow to Larimar, as the company had already been studying varying doses within a Phase 1 trial. The trial highlighted how CTI-1601, administered subcutaneously, helped increase frataxin levels. Within this trial, doses were given at 50-100mg. Now, this trial has been halted. An additional trial, which was meant to start later this year, and a private financing deal, have also been squashed.

Larimar must now wait for the FDA decision. However, the company has stated that it is hopeful about a future for CTI-1601.

Friedreich’s Ataxia (FRDA)

FXN gene mutations cause Friedreich’s ataxia, a rare genetic disease which causes progressively worsening neurological and movement difficulties. Normally, FXN codes for frataxin production. Frataxin is found throughout the body, from the heart, spinal cord, and liver to the pancreas and voluntary muscles. It plays a role in mitochondrial function and energy. When the body fails to produce enough frataxin, cell degeneration occurs, causing a variety of health issues. Typically, symptom onset occurs between ages 5-15. However, around 25% of patients have late-onset FRDA which appears after 25 years old. Another small portion of patients have very late-onset FRDA, where symptoms do not appear until after 40. In these cases, FRDA usually progresses more slowly. An estimated 1 in every 40,000 Americans has FRDA.

Symptoms include:

  • Slurred or slowed speech
  • Diabetes
  • Scoliosis (abnormal spinal curvature)
  • Hearing and vision loss
  • Chest pain
  • Shortness of breath
  • Movement difficulties
  • Loss of reflexes
  • Muscle weakness
  • Foot deformities
  • Heart palpitations
  • Fatigue
  • Loss of coordination
Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

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