** Larimar Therapeutics' LRMR.O shares fall 22.2% to $2.84 premarket

** LRMR has begun rolling submission for accelerated U.S. FDA approval of its drug nomlabofusp, a daily injection for Friedreich's ataxia, a rare and progressive nerve disease

** Company says FDA has signaled that LRMR's existing data sufficient to support a full review, with a potential mid-2027 launch, if approved

** Larimar reported cases of anaphylaxis in its latest study update, after similar safety concerns flagged last year

** Ten of 43 patients experienced anaphylaxis, a sudden and severe allergic reaction that can cause breathing problems, swelling and a drop in blood pressure

** Long-term study data shows patients on the drug for one year improved protein levels and signs of clinical benefit

** Company says about 21 of the 43 patients in the ongoing study have dropped out

** As of last close, stock down ~4% YTD