Larimar Therapeutics, Inc.

Consistent Long-term Safety Profile.

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Longer-term dosing was generally well tolerated with thirteen adults on treatment for one year, seven for 18 months and three for two years.

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The most common adverse events remained mild-to-moderate local injection site reactions, which decreased in frequency over time and did not lead to any withdrawals from the study.

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Twenty-one participants discontinued since study initiation in January 2024.

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Ten participants experienced anaphylaxis and discontinued the study, including nine participants with prior nomlabofusp exposure; all participants who experienced anaphylaxis responded to standard therapy and all returned to their usual state of health with no further sequelae.

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Three participants experienced generalized urticaria and discontinued the study, with no new occurrences observed following initiation of antihistamine therapy.

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Other discontinuations included three associated with other adverse events and five discontinuations unrelated to treatment, primarily due to logistical factors.

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Of the eleven participants who had previously not been exposed to nomlabofusp, one had anaphylaxis.

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Sustained Increases in Skin FXN Levels Comparable to Asymptomatic Carriers. Skin frataxin (FXN) levels increased following nomlabofusp administration, with 82% (9/11) of participants achieving levels above those in asymptomatic carriers by six months, 100% (9/9) reaching this threshold at one year, and 100% (3/3) maintaining it through 18 months.

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