BLA for Rocket’s LAD-I Gene Therapy Under Review by FDA Again

The FDA has accepted Rocket Pharmaceuticals’ resubmission of a biologics license application (BLA) for marnetegragene autotemcel (RP-L201, to be marketed as Kresladi), a genetically modified autologous hematopoietic stem cell therapy intended to treat leukocyte adhesion deficiency type 1 (LAD-I).¹

The FDA has set the Prescription Drug User Fee Act (PDUFA) action date for the BLA at March 28, 2026. Data from a global phase 1/2 clinical trial (NCT03812263) that showed a 100% overall survival rate in all enrolled patients for at least 1 year post treatment, and through the entire duration of follow-up, support the BLA. According to Rocket, this trial met all of its primary and secondary end points, with the incidence of significant infections having decreased substantially in comparison with levels before treatment and observed indications of skin lesion improvement and restored wound-healing capability. With regard to safety, Rocket noted that Kresladi was “well tolerated” and that there were no serious adverse events deemed related to treatment reported in the now completed study.¹

“We value the continued dialogue with the FDA and believe the BLA moves Rocket closer to our goal of delivering a onetime gene therapy to patients facing the devastating effects of severe LAD-I,” Gaurav Shah, MD, the CEO of Rocket, said in a statement.¹ “For these patients, survival beyond childhood is uncommon. Bone marrow transplant is currently the only treatment option; has substantial morbidity, mortality, and cost; and may not be available in time for these children. As we approach our new PDUFA date, we are focused on the opportunity to make this therapy available to patients who need it most.”

Rocket previously submitted a BLA to the FDA for Kresladi that was accepted by the FDA with priority review in October 2023.² This initial BLA was met with a complete response letter (CRL) in June 2024 related to a request for more Chemistry Manufacturing and Controls (CMC) information.³ Rocket stated at the time that it had met with FDA officials and aligned on the “limited” information requested. The CRL marked the second time the FDA has requested more CMC information, after the agency had extended its priority review for Kresladi, pushing back the BLA’s original PDUFA date from March 31, 2024, to June 30 to allow additional time to review clarifying information submitted by Rocket in response to FDA information requests.⁴

In 2022, CGTLive® spoke with primary investigator of the phase 1/2 trial Donald B. Kohn, MD, distinguished professor of microbiology, immunology, molecular genetics, and pediatrics (hematology/oncology) and director of the Human Gene Medicine Program at UCLA. Kohn discussed the data from the study that had been presented at the 2022 American Society of Gene & Cell Therapy Annual Meeting, from May 16 to 19, 2022, in Washington, DC.⁵

Notably, earlier this month, Rocket voluntarily withdrew a BLA for one of its other investigational gene therapy products, mozafancogene autotemcel (also known as fanca-cel and RP-L102), which was in development for Fanconi anemia.⁶ Rocket quietly announced the move in a United States Securities and Exchange Commission (SEC) Form 8-K, citing corporate prioritization as the reason for its decision. The company specifically pointed out that it intends to focus its resources on “programs with the clearest regulatory and commercial pathways” and that it had stopped investing resources in the development of RP-L102 as of July 2025.

“The Company’s decision to withdraw the BLA is based on business and strategic considerations and does not reflect concerns regarding the safety or efficacy profile of RP-L102,” Rocket wrote in the SEC document.⁶

REFERENCES
1. Rocket Pharmaceuticals announces FDA acceptance of BLA resubmission of KRESLADI for the treatment of severe leukocyte adhesion deficiency-I (LAD-I). News release. Rocket Pharmaceuticals Inc. October 14, 2025. Accessed October 14, 2025. https://ir.rocketpharma.com/news-releases/news-release-details/rocket-pharmaceuticals-announces-fda-acceptance-bla-resubmission
2. Rocket Pharmaceuticals announces FDA acceptance of biologics license application with priority review for RP-L201 (marnetegragene autotemcel) for the treatment of severe leukocyte adhesion deficiency-I (LAD-I). News release. Rocket Pharmaceuticals Inc. October 2, 2023. Accessed October 14, 2025. https://www.biospace.com/article/releases/rocket-pharmaceuticals-announces-fda-acceptance-of-biologics-license-application-with-priority-review-for-rp-l201-marnetegragene-autotemcel-for-the-treatment-of-severe-leukocyte-adhesion-deficiency-i-lad-i-/
3. Rocket Pharmaceuticals provides regulatory update on KRESLADI (marnetegragene autotemcel; marne-cel). News release. Rocket Pharmaceuticals Inc. June 28, 2024. Accessed October 14, 2025. https://finance.yahoo.com/news/rocket-pharmaceuticals-provides-regulatory-kresladi-112700392.html
4. Rocket Pharmaceuticals announces update on FDA review timeline of KRESLADI (marnetegragene autotemcel) for the treatment of severe leukocyte adhesion deficiency-I (LAD-I). News release. Rocket Pharmaceuticals Inc. February 13, 2024. Accessed October 14, 2025. https://www.biospace.com/article/releases/rocket-pharmaceuticals-announces-update-on-fda-review-timeline-of-kresladi-marnetegragene-autotemcel-for-the-treatment-of-severe-leukocyte-adhesion-deficiency-i-lad-i-/
5. Kohn DB, Sevilla J, Rao G, et al. 1188: interim results from an ongoing phase 1/2 study of lentiviral-mediated ex-vivo gene therapy for pediatric patients with severe leukocyte adhesion deficiency-I (LAD-I). Presented at: 2022 American Society of Gene & Cell Therapy Annual Meeting; May 16-19, 2022; Washington, DC.
6. Form 8-K, United States Securities and Exchange Commission. Rocket Pharmaceuticals. October 3, 2025. Accessed October 14, 2025. https://ir.rocketpharma.com/node/12966/html