Purespring Therapeutics has reeled in £80 million ($105 million) to test two gene therapies in humans.
The Sofinnova Partners-led Series B, disclosed Wednesday morning, will carry the London startup into an open-label Phase 1/2 next year for a kidney disease that has attracted a lot of attention in recent years from regulators and pharmaceutical acquirers.
The startup’s lead gene therapy, PS-002, will be investigated for IgA nephropathy, or IgAN. The autoimmune and kidney disease, in which too much IgA protein stays in the kidneys, can lead to end-stage renal disease.
Julian HanakPurespring anticipates it could snag an accelerated approval from its upcoming Phase 1/2, CEO Julian Hanak told Endpoints News. Travere, Novartis and Calliditas have received FDA nods in the past few years for their oral medicines.
During that approval process, Purespring would plan to launch a confirmatory Phase 3 to get full approval, Hanak said. To fund that, Purespring would have a few options: raise a crossover round, go through an IPO and/or secure a commercialization partnership with a pharma company, the CEO said.
Purespring’s experimental gene therapy goes after a particular cell type known as the podocyte, which is key to a kidney’s ability to operate. Judo Bio, a new siRNA startup that emerged earlier this week with $100 million, also plans to target podocytes to directly treat renal diseases.
Purespring’s candidate “actually could work in conjunction and in complementation with some of the new therapies coming on the market,” Hanak said. “It’ll be a one-and-done therapy because it’s gene therapy and because podocytes are totally differentiated, non-dividing cells. Once the gene therapy is in them, we’ll get persistence of expression.”
There’s been a wave of M&A in the IgAN field, with Novartis, Vertex and Biogen each dishing out more than $1 billion to buy clinical-stage drug developers Chinook, Alpine Immune Sciences and Human Immunology Biosciences, respectively, in the past 15 months.
“I think the industry has woken up to the fact that this is a huge unmet medical need,” Hanak said. He initially joined Purespring as chief development officer in 2021, coming from Biogen, where he served as CMC leader for the gene therapy work acquired from Nightstar.
More kidney diseases
Purespring could go into “any other complement-mediated kidney disease affecting podocytes, so lupus nephritis, ANCA vasculitis and so on,” Hanak said, but the initial focus is on IgAN and an undisclosed second indication that will enter the clinic before the Series B runs out in a few years.
The startup could also ink partnerships over the coming two years, the CEO said. “Companies have been approaching us about access to our platform to deliver their genes to the kidney,” he added.
It has an internal process development manufacturing setup, Hanak said, noting the company also works with Charles River for plasmid DNA and with Columbus, OH-based Andelyn Biosciences for vector supplies.
“We have to get the cost of goods for the product down, which we’ve been able to do,” Hanak said. “Our dose is very low, 50-to-100-fold lower than a traditional, systemic gene therapy because of our platform.”
Purespring derived from the work of University of Bristol professor Moin Saleem, who works in pediatric renal medicine. The company launched with a £45 million Series A from Syncona in November 2020.
Syncona returned for the Series B alongside Forbion. The respective UK and Dutch investors have paired up with other gene therapy companies before, including a $170 million round for ophthalmology-focused Beacon Therapeutics in July.
Other Purespring investors include Gilde Healthcare and British Patient Capital.
The company has 46 employees and doesn’t plan to rapidly hire. “We have all the juice we need to deliver,” Hanak said.