Silence Therapeutics is snatching back two siRNA drug targets developed through a $20 million collaboration with Mallinckrodt.
The two companies agreed in 2019 to develop three siRNA drug targets that would silence the complement cascade in complement-mediated disorders. One of the programs, SLN500, has produced a candidate called SLN501, which is listed in Mallinckrodt’s pipeline as a phase 1 asset.
But now Silence wants the other two programs back to continue work, according to a Tuesday press release. The biotech will not have to make any payments under the terms of the deal, but Mallinckrodt will be eligible for success-based milestones and royalties on net sales if the candidates advance. Financial details of the agreement were not disclosed.
The deal was originally worth $20 million upfront with $2 billion on the line for Silence for all three programs. For the SLN500 program, Silence could have received $10 million in research milestones for each candidate advanced, plus a further $663 million in clinical, regulatory and commercial milestones. The remaining programs were worth up to $703 million in milestones for each asset that emerged.
Silence received a $2 million payment from Mallinckrodt in April 2021 when pre-clinical development work for the SLN500 program advanced. At that time, Silence said SLN501 was moving towards investigational new drug-enabling studies. In May 2022, Silence reported a $3 million milestone payment when a clinical trial application was filed for the therapy.
The two programs aren’t all that Silence is getting back from Mallinckrodt. The company also poached the U.K. pharma’s Chief Scientific Officer Steven Romano, M.D., who will now serve as Chief Medical Officer and Head of Research and Development at Silence, according to a separate release issued Tuesday morning. Romano joined Silence’s board in July 2019 with the signing of the original collaboration and has been overseeing the biotech’s complement portfolio. He previously served 16 years at Pfizer before arriving at Mallinckrodt.
Romano will replace Giles Campion, M.D., who will retire at the end of the year.