Other biotechs have also emerged, including one literally named PSMA TherapeuticsPSMA Therapeutics, hoping to go after that same target with a targeted radiation drug. Aktis, while still a radioligand biotech, wants to take the success Endocyte and Novartis had in PSMA-positive prostate cancer to a myriad of other indications, though it won’t say what they are. Aktis CEO Matthew Roden did offer that the biotech has two lead programs, and “we are not going after PSMA.” “Rather we took that finding and said we need to find a way to translate that into other commonly occurring tumor types,” Roden told Endpoints News. So Aktis is building out a platform of mini-proteins that could direct radiation in the form of decaying atoms to an array of tumors. And now, the biotech has an additional $84 million to develop that portfolio and build out its radioisotope supply. Aktis was born from MPM Capital in 2020 and launched from stealth a year later with $72 million, which included backing from Novartis and Bristol Myers Squibb. Now, the biotech has added a third Big Pharma backer in Merck’s venture arm. Novartis bet $6B on the idea — now Versant, venBio have $45M to birth a platform play for radiopharmaceuticals Aside from developing its homing protein platform, Aktis has also been tackling a key issue in the targeted radiation field — radioisotope supply. Radioisotopes, these large (relatively speaking), decaying atoms, are the crux of the approach: The particles they emit are lethal to cells. But Actinium-225, the radioisotope Aktis and others are using, hadn’t had much purpose before targeted radiotherapy came along.
So prior to 2020, when a key paper on an Actinium-225 radiotherapy was published, no one really was capable of making Actinium-225 at scale, Roden said.
The supply issue is further complicated by the very nature of radioisotopes — they decay.
“You can’t really build up an inventory of a drug that has a decaying isotope in it, so you have to make fresh ones every week,” Roden noted.
On Tuesday, Aktis announced three Actinium-225 supply contracts which use different methods to make the radioisotope. Roden said they will give Aktis access to the isotope through its preclinical, clinical and even commercial stages.
“That’s necessary, but not sufficient to have the end-to-end supply chain, and we have lots of work ongoing to continue to build out that network of supply that’s needed to deliver what we intend to be mainstream anti-cancer agents,” Roden said. The radioligand space has grown substantially in the past few years. Novartis has been the frontrunner here, with two approved drugs in Pluvicto and Lutathera, which is indicated for certain digestive tract cancers. Versant and venBio unveiled RayzeBio in 2020. And last year, Bayer bought PSMA TherapeuticsPSMA Therapeutics and its fellow Weill Cornell spinout Noria to buoy its own radiation therapy pipeline. Also last year, German biotech ITM raised $109 million as its radioligand for digestive tract cancers is going through a Phase III study. Just yesterday, the Australian biotech AdvanCell disclosed an $18 million AUD round led by Morningside. Other new investors in Aktis included Cowen Healthcare Investments, MRL Ventures Fund, ArrowMark Partners, Mirae Asset Venture Investment, Timefolio Capital, and Pappas Capital. Aktis’ existing investors — MPM Capital, Vida Ventures, EcoR1 Capital, Octagon Capital, TCG Crossover, Bristol Myers Squibb, and Novartis — also pitched in.