Core Insights - Rocket Pharmaceuticals (RCKT) received FDA accelerated approval for its gene therapy Kresladi (marnetegragene autotemcel) to treat severe leukocyte adhesion deficiency-I (LAD-I), an ultra-rare genetic disorder [1][7] - Kresladi is the first gene therapy approved for children with severe LAD-I due to biallelic variants in ITGB2 without a matched sibling donor for allogeneic hematopoietic stem cell transplant [2][7] - Despite the approval, RCKT shares fell by 20% following the announcement [2][6] FDA Approval Details - The FDA approved Kresladi ahead of the expected decision date, which was initially set for March 28, 2026 [5][6] - The approval was based on the treatment's ability to increase specific immune cell markers (CD18 and CD11a), with long-term clinical benefits to be confirmed through further studies [6][8] - The company received a Rare Pediatric Disease Priority Review Voucher (PRV) as an incentive for developing treatments for rare diseases, which it plans to monetize for financial flexibility [7][8] Market Performance - RCKT's stock has increased by 7.4% year-to-date, contrasting with a 0.6% decline in the industry [4] - The stock's decline post-approval may reflect investor sentiment regarding the need for long-term data to validate the treatment's efficacy [6] Historical Context - Prior to the recent approval, the FDA had issued a complete response letter (CRL) in June 2024, requesting additional information on the Chemistry Manufacturing and Controls (CMC) related to Kresladi [9][10] - This was the second request for additional information from the FDA, indicating a challenging regulatory pathway for the product [10]