Aktis Oncology Inc. said it closed its upsized initial public offering (IPO) on January 12, 2026, selling 17.65 million shares of common stock at $18.00 per share. The underwriters also exercised in full their option to purchase an additional 2.65 million shares at the same price, bringing total gross proceeds to approximately $365.4 million before underwriting discounts and offering expenses.
The company’s common stock began trading on the Nasdaq Global Select Market on January 9 under the ticker symbol AKTS.
The IPO brings new capital to the Boston-based, clinical-stage biotech company as it advances a pipeline of targeted radiopharmaceuticals for solid tumors.
Aktis develops these therapies using a proprietary platform of small, engineered proteins known as miniproteins. These molecules are designed to bind selectively to specific proteins on the surface of tumor cells and carry radioactive payloads to those sites.
In the prospectus, the company said that the miniproteins are large enough to achieve antibody-like specificity, yet small enough to penetrate solid tumors efficiently and clear more quickly from normal tissues. The same targeting molecules can be linked to imaging or therapeutic isotopes, allowing the platform to support both tumor visualization and targeted radiation delivery.
Aktis’ most advanced program, [225Ac]Ac-AKY-1189, targets Nectin-4, a surface protein expressed in urothelial cancer and several other solid tumor types, with limited expression in most normal adult tissues. The drug candidate consists of a Nectin-4-binding miniprotein linked to actinium-225, an alpha-emitting radioisotope.
Aktis is evaluating the compound in a multi-site Phase Ib clinical trial in the US for patients with locally advanced or metastatic urothelial cancer and other Nectin-4-expressing tumors. The study is designed to assess safety, radiation distribution and early clinical signals, with preliminary dose-escalation results expected in 2027.
A second clinical program, [225Ac]Ac-AKY-2519, targets B7-H3, another tumor-associated surface protein found in a range of solid cancers, including prostate, lung and breast tumors. Aktis has completed early imaging and dosimetry studies using diagnostic versions of this construct and plans to submit an Investigational New Drug application (IND) in the first half of 2026. If cleared by the FDA, the company intends to initiate a Phase Ib trial in the second half of the year.
Beyond its wholly owned pipeline, Aktis also has a discovery collaboration with Eli Lilly focused on generating new targeted radiopharmaceutical candidates against tumor targets outside its internal programs, while retaining global development and commercialization rights to its proprietary portfolio. The IPO proceeds will be used to support these development efforts.
Aktis expects to allocate approximately $140 million to $150 million to advance the ongoing Phase Ib trial of its Nectin-4-targeted program and about $70 million to $80 million to move the B7-H3 program into Phase Ib testing.
In parallel, the company is building out isotope supply partnerships and an internal current good manufacturing practice facility to support clinical manufacturing and future scale-up. The facility is expected to become operational in the second half of 2026.
Alongside miniprotein-based targeting approaches such as those being developed by Aktis, other groups are advancing a range of radiopharmaceutical formats, including antibody-based radioligand therapeutics and radioantibody conjugates designed to deliver alpha-emitting isotopes to well-validated tumor targets.
In January, Swiss Rockets and Alloy Therapeutics announced a multi-target research collaboration to generate new antibody-based radioligand therapeutics, combining discovery platforms with radiochemistry and isotope development.
In parallel, Convergent Therapeutics expanded its partnership with NorthStar Medical Radioisotopes to secure dedicated actinium-225 manufacturing capacity for its PSMA-targeted (a cell-surface protein highly expressed in prostate tumors) alpha-emitting radioantibody in late-stage development for metastatic castration-resistant prostate cancer.
Actinium Pharmaceuticals has also reported new preclinical data for its actinium-225-based antibody radioconjugate ATNM-400 in solid tumor models.
If you want your company to be featured on Xtalks.com, please email [email protected].
Join or login to leave a comment
JOIN LOGIN