Rampart Bioscience, a startup focused on developing DNA-based therapies without using viral vectors, has reportedly shut down less than two years after its launch. The closure was first reported by Endpoints News after interviews with two former employees. According to one source, the company had already undergone two rounds of downsizing in the previous year. Rampart’s website and LinkedIn page are no longer accessible.
BioSpace reached out to CEO Louis Breton and other staff members for confirmation but did not receive an immediate response.
Rampart launched from stealth mode in October 2023, announcing $85 million in Series A funding in addition to $40 million in seed capital. The company centered its efforts on a proprietary platform called HALO, which it said could avoid the risks associated with viral vector delivery methods commonly used for gene therapies.
Viral vectors are currently the main method for delivering genetic medicines into cells but can lead to serious or even fatal side effects. These risks became prominent when Sarepta Therapeutics’ Duchenne muscular dystrophy therapy Elevidys was linked to patient deaths last year. In March 2025, one patient died from severe acute liver failure while on the therapy; another death was reported in June.
Rampart aimed to address these safety issues but did not provide detailed public explanations about its technology. The company disclosed only limited information about its approach, stating that its assets “contain novel structural elements that drive nuclear trafficking and retention while avoiding immune responses,” according to Jefferey Bartlett, co-founder and chief innovation and technical officer, during the Series A announcement in October 2023.
The company was listed among BioSpace’s NextGen Class of 2025 as one of the most anticipated emerging biotechs. Rampart intended to use its HALO platform to develop treatments for hypophosphatasia, a rare disorder affecting bone mineralization, though this program did not advance to clinical trials.
