FDA Activity Recap: March 2025 Features FDA Approvals in Hemophilia, ATTR Amyloidosis, and More

Last month, March 2025, the CGTLive^® team was diligently tracking the FDA's activities related to the development of cell and gene therapies for the treatment of rare, complex, and otherwise challenging diseases and disorders.

The agency has continued to ramp up its activities around these therapies as more of them progress through the pipeline in tandem. Last month proved no different, with the FDA approving Sanofi's fitusiran, an siRNA therapeutic intended to lower antithrombin, for use as routine prophylaxis in hemophilia A or hemophilia B, and Alnylam Pharmaceuticals' subcutaneous RNA interface therapy vutrisiran, marketed as Amvuttra, for the treatment of cardiomyopathy of wild-type or hereditary transthyretin-mediated amyloidosis (ATTR-CM). Our team has highlighted these, and several other important actions, below.

Click the read more buttons for more details and information about each update.

FDA Approves Sanofi’s siRNA Therapy Fitusiran for the Treatment of Hemophilia A and B

March 31, 2025 — The FDA has approved Sanofi's fitusiran, an siRNA therapeutic intended to lower antithrombin, for use as routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adult and pediatric patients aged 12 years and older with hemophilia A or hemophilia B, with or without factor VIII or IX inhibitors. The therapy will be marketed under the name Qfitlia.

Fitusiran is specifically expected to increase the production of thrombin by decreasing levels of antithrombin, with the goal of hemostasis restoration. The FDA's decision was made based on data from the ATLAS clinical development program, which includes the completed phase 3 clinical trials ATLAS-INH (NCT03417102), ATLAS-A/B (NCT03417245), and ATLAS-PPX (NCT03549871) and the ongoing phase 3 clinical trials ATLAS-NEO (NCT05662319), ATLAS-PEDS (NCT03974113), and ATLAS OLE (NCT03754790). Notably, the FDA also approved Siemens Healthineers’ companion diagnostic for fitusiran, refereed to as Innovance Antithrombin Assay, which is to be used to assess antithrombin levels in patients who have been prescribed fitusiran

“Qfitlia delivers the fewest doses of any prophylactic therapy in hemophilia, and its unique mechanism allows it to be used to treat all types of hemophilia, including with inhibitors and hemophilia B, where unmet medical needs remain," Guy Young, MD, the director of the Hemostasis and Thrombosis Center at Children's Hospital, Los Angeles, said in a statement. "By targeting antithrombin, which can be reliably measured with an FDA-cleared blood assay, Qfitlia is proven to help rebalance hemostasis and improve bleed rates and protection.”

FDA Accepts BLA for Capricor’s DMD Cardiomyopathy Cell Therapy Deramiocel With Priority Review

March 4, 2025 — The FDA has accepted the biologics license application (BLA) that Capricor Therapeutics submitted for Deramiocel (also known as CAP-1002), an investigational allogeneic cardiosphere-derived cell therapy intended to treat Duchenne muscular dystrophy (DMD) cardiomyopathy, with priority review. The agency has set the Prescription Drug User Fee Act (PDUFA) action date for the BLA as August 31, 2025.

According to Capricor, the FDA indicated it had not yet made a decision regarding whether an Advisory Committee meeting will be necessary during the review process, but that no potential review issues were noted by the agency. The BLA is supported by results from the completed HOPE-2 clinical trial (NCT03406780) and HOPE-2’s ongoing open-label extension (OLE) study (HOPE-2-OLE; NCT04428476), with data from these studies being compared to an FDA funded natural history dataset.

"We are thrilled to announce the acceptance of our BLA bringing us one step closer to providing this first-in-class treatment for Duchenne-cardiomyopathy, a condition for which there are no approved therapies" Linda Marbán, PhD, chief executive officer of Capricor Therapeutics, said in a statement. “If our application is successful, we expect deramiocel to be a lifelong treatment, administered quarterly, with the potential to be widely adopted across the DMD-cardiomyopathy treatment landscape. We want to extend our appreciation to the patients, their families and advocates who continue to work with Capricor and to the FDA for its commitment to accelerating treatments for DMD.”

Neurotech’s Encapsulated Cell Therapy Encelto Approved by FDA for Macular Telangiectasia Type 2

March 6, 2025 — Neurotech Pharmaceuticals’ revakinagene taroretcel-lwey (also known as NT-501), an allogeneic encapsulated cell therapy implant, has been approved by the FDA for the treatment of adults with idiopathic macular telangiectasia type 2 (MacTel). It is to be marketed under the name Encelto.

Notably, the therapy is the first therapy to be approved for MacTel. Neurotech expects that the therapy will become available in the United States in June 2025.

"This is a historic moment for the MacTel community, as Encelto becomes the first-ever FDA approved treatment for this vision-threatening disease,” Thomas M. Aaberg Jr, MD, the chief medical officer of Neurotech, said in a statement. “For those who have been affected by MacTel and for all who have supported this journey, today we look forward to a future where vision loss from MacTel may be slowed."

FDA Approves Alnylam’s Vutrisiran for the Treatment of ATTR Amyloidosis With Cardiomyopathy

March 20, 2025 — The FDA has approved Alnylam Pharmaceuticals' subcutaneous RNA interface therapy vutrisiran, marketed as Amvuttra, for the treatment of ATTR-CM. The therapy is approved for adult patients.

The therapy is specifically meant to cut down on cardiovascular mortality, cardiovascular hospitalizations, and urgent heart failure visits. Vutrisiran was approved for ATTR-CM on the basis of a supplemental New Drug Application (sNDA) submitted by Alnylam; the therapy had previously been approved by the FDA on June 13, 2022, for polyneuropathy manifestations of hereditary ATTR Amyloidosis (hATTR-PN).

“The FDA approval of Amvuttra for ATTR-CM marks a pivotal advancement for patients, providing a new and clinically differentiated treatment option that has been shown to improve outcomes, including cardiovascular mortality, and reduce progression for those living with this devastating disease,” Yvonne Greenstreet, MBChB, the chief executive officer of Alnylam, said in a statement. “I would like to extend my deepest gratitude to the patients who participated in our clinical trials, their families and caregivers, the clinical researchers, regulators, and my colleagues at Alnylam who made this approval possible. Today represents a significant milestone in our nearly 20 years of partnership with the ATTR amyloidosis community, but we are not stopping here. We will continue to innovate for patients with ATTR amyloidosis so they can live longer, better, healthier lives.”