SwanBio raises $56m for rare neurological disease gene therapy

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SwanBio Therapeutics has raised $56 million in a second-round financing that will be used to advance its lead gene therapy candidate for adrenomyeloneuropathy (AMN) into clinical testing later this year.

The Series B takes the total raised by the Philadelphia-based biotech to $133 million and is earmarked for a phase 1/2 trial of the gene therapy – codenamed SBT101 – in the second half of this year.

The news follows a report in Endpoints last month that SwanBio had laid off around a quarter of its workforce after struggling to finalise the funding round.

SBT101 is an adeno-associate virus (AAV) based gene therapy that has been shown in preclinical studies to reduce disease markers and symptoms in mouse and non-human primate models of AMN, a progressive, inherited, and debilitating neurodegenerative disease.

AMN is a form of X-linked adrenoleukodystrophy (ALD) that is caused by a deficiency in the ABCD1 gene, which disrupts the function of cells in the spinal cord and other tissues, leading to the accumulation of toxic very long-chain fatty acids (VLCFAs) in some organs.

The disease causes nerves to degenerate and often impairs the function of the adrenal gland causing a range of symptoms including loss of mobility, incontinence, pain, and sexual dysfunction.

The prevalence of ALD is estimated as between one in 20,000 and one in 50,000 individuals worldwide, and AMN accounts for around 25% to 46% of all ALD cases.

Gene therapies have already been tested for other forms of ALD, which include cerebral adrenoleukodystrophy (CALD),  a severe form of a rare inherited neurological disease, as well as adrenal insufficiency disorder Addison's disease.

Last year, bluebird bio secured regulatory approval in the EU for its CALD gene therapy Skysona (elivaldogene autotemcel), although the biotech withdrew it from the market after deciding it was not feasible to make a viable gene therapy business in Europe.

SBT101 is set to be the first gene therapy for AMN to reach the clinical testing stage, and has already been cleared to start the phase 1/2 trial by the FDA, which has also awarded orphan drug and fast track status to the programme. The therapy is designed to compensate for the disease-causing ABCD1 gene.

Along with helping to fund the clinical trial, the latest cash injection will also be used to bring forward other gene therapies in SwanBio's pipeline, which includes candidates for other forms of spastic paraplegia as well as neuropathies caused by genetic mutations.

The Series B was led by SwanBio's founding investors Syncona Limited and Mass General Brigham Ventures.