Regenxbio said the FDA will reconsider its mucopolysaccharidosis type II (Hunter syndrome) gene therapy (Navsunli / RGX-121) after the agency rejected the filing earlier this year. Regenxbio said FDA staff acknowledged its existing clinical data as sufficient for the accelerated approval pathway without requiring a new placebo-controlled trial. The company expects to resubmit in the third quarter. Regenxbio described that the FDA aligned on “next steps” after discussions over issues previously flagged—most notably uncertainty about eligibility criteria and concerns about the comparability of external controls. The reversal adds to a pattern of regulatory walkbacks under new leadership in recent weeks, with similar reconsiderations reported for other rare-disease programs. Market focus now shifts to what labeling discussions and resubmission timelines look like as Regenxbio prepares its next FDA package.