Larimar Therapeutics, Inc. ("Larimar") (Nasdaq: LRMR), a clinical-stage biotechnology company focused on developing treatments for Friedreich's ataxia (FA) and other complex rare diseases, today announced that the United States Food and Drug Administration (FDA) has placed a clinical hold on the CTI-1601 clinical program and that the company will not be closing a previously announced private placement financing. CTI-1601 is a recombinant fusion protein intended to deliver human frataxin into the mitochondria of patients with FA who are unable to produce enough of this essential protein.

The clinical hold follows the previous notification by Larimar to the FDA of mortalities which occurred at the highest dose levels in an ongoing 180-day non-human primate (NHP) toxicology study, which is designed to support extended dosing of patients with CTI-1601. In the clinical hold letter, the FDA stated it needs a full study report from the ongoing NHP study and Larimar may not initiate additional clinical trials until the company has submitted the report and received notification from the agency that additional clinical trials may commence.

"While the notification of a formal clinical hold is disappointing, it does not change our previously stated clinical development strategy for CTI-1601," said Carole Ben-Maimon, MD, President and Chief Executive Officer of Larimar. "Patient safety is our top priority, and we will continue with our plan to complete the NHP toxicology study, assess the data, and discuss that data with FDA to obtain their consent prior to initiating our Jive and pediatric MAD trials. Based on all of the information we have regarding CTI-1601's safety profile to date, we continue to believe there is a path forward toward the initiation of our Jive and pediatric MAD trials. However, due to the additional regulatory requirements that come with responding to a formal clinical hold, we believe there is a possibility that the initiation of these trials may be delayed into 2022. Regarding the termination of the previously announced private placement financing, as of March 31, 2021, we have $81.4 million in cash and investments, which provides cash runway through the first half of 2022."

The safety of CTI-1601 was previously evaluated in Phase 1 single- and multiple-ascending dose clinical trials. Recently announced data from these trials indicate that repeated subcutaneous injections of CTI-1601 were generally well tolerated at doses up to 100 mg administered daily for 13 days. No serious adverse events, important medical events, or treatment-related severe adverse events were reported in the trial and the number and severity of adverse events did not increase with increasing exposure to CTI-1601. The most common adverse events were mild and moderate injection site reactions. Data from the MAD trial also showed that daily subcutaneous injections of CTI-1601 at doses of 50 mg or 100 mg resulted in frataxin levels in peripheral tissues (buccal cells) that were at or in excess of those that would be expected in phenotypically normal heterozygous carriers.

About CTI-1601

CTI-1601 is a recombinant fusion protein intended to deliver human frataxin into the mitochondria of patients with Friedreich's ataxia who are unable to produce enough of this essential protein. Currently in Phase 1 clinical trials in the U.S., CTI-1601 has been granted Rare Pediatric Disease designation, Fast Track designation and Orphan Drug designation by the U.S. Food and Drug Administration (FDA), Orphan Drug Designation by the European Commission, and PRIME designation by the European Medicines Agency.

About Larimar Therapeutics

Larimar Therapeutics, Inc. (Nasdaq: LRMR), is a clinical-stage biotechnology company focused on developing treatments for complex rare diseases. Larimar's lead compound, CTI-1601, is currently being evaluated in a Phase 1 clinical program in the U.S. as a potential treatment for FA. Larimar also plans to use its intracellular delivery platform to design other fusion proteins to target additional rare diseases characterized by deficiencies in intracellular bioactive compounds.