Regeneron is turning its attention to radiopharmaceuticals as the latest anti-obesity measures start to pay off.
The New York-based biopharmaceutical company is paying Australia’s Tellix Pharmaceuticals $40 million upfront to initially work on four solid tumor programs. Regeneron selects specific targets based on its proprietary antibody portfolio.
The idea is to leverage Telix’s radiopharmaceutical manufacturing platform to advance these four programs. According to the April 13 release, Regeneron also has the option to expand the partnership to four more programs in exchange for a larger upfront payment.
If a product is brought to market, Telix and Regeneron will split global commercialization costs and profits, with Telix also retaining the option to jointly promote certain potential products. If Telix decides to opt out of this co-funding model for any of its programs, it could instead receive up to $535 million in development and commercial milestones per program and low double-digit royalties on net sales.
This means that if Telix does not adopt a cost-sharing model for all four programs, it could potentially earn up to $2.1 billion in biobacks, assuming each reaches all milestones.
Israel Lowy, MD, Regeneron’s head of oncology clinical development, suggested that these radiopharmaceuticals could be combined with the company’s blockbuster cancer drug Libtayo.
“Regeneron is excited to enter the targeted radiopharmaceutical space and explore the utility of these agents as monotherapy or in rational combination with our immunotherapy platform, particularly in areas with unmet patient needs, such as lung cancer, where our PD-1 inhibitors are the global standard of care,” Loewy said in the release.
Regeneron likely hopes its radiopharmaceutical business will be as productive as its recent further foray into obesity. Regeneron, which paid $80 million upfront in 2025 to secure a third-stage GLP-1/GIP dual agonist from Hanso Pharma, reported data from its Chinese partner last month suggesting the therapy could be comparable to Eli Lilly’s Zepbound in terms of weight loss.
“At Regeneron, we follow science to determine the best treatment approach for each disease and are continually expanding our toolbox of therapeutic avenues, from monoclonal and bispecific antibodies to cell therapies and more,” said John Lin, MD, Regeneron’s senior vice president of oncology and antibody technology research.
“Targeted radiopharmaceuticals are a rapidly emerging frontier in the field of oncology and an exciting opportunity to bring new treatment options to patients in need,” Lin added.
When it comes to radiopharmaceuticals, Telix is your best bet. The Melbourne-based biotech company had at one time been planning a $200 million Nasdaq IPO in 2024, but had second thoughts at the last minute. Instead, Telix focused its energies on fleshing out its radiopharmaceutical capabilities, acquiring Texas-based CDMO IsoTherapeutics for $13.6 million and acquiring ARTMS and its cyclotron-based isotope production platform for $82 million.
Additionally, Telix acquired RLS Radiopharmacies to secure access to the RLS network of 31 radiopharmacies across the United States and purchased certain assets from radiopharmaceutical company ImaginAb.
Since then, Telix has confirmed “promising efficacy” for its radiation therapy TLX101 in a small, single-arm study in brain tumor patients. However, the company’s diagnostics portfolio suffered some regulatory setbacks last year when the FDA withheld approval of Telix’s glioma contrast agent Pixclara and kidney cancer diagnostic Zircaix.
Interestingly, the collaboration between Regeneron and Telix will also extend to diagnostics, with the companies saying only that Telix will lead the commercialization of these assets and Regeneron will receive “a percentage of the profits.”
“Our partnership with Regeneron reflects a highly complementary set of capabilities and a unique opportunity to explore what a truly ‘next generation’ biologic-based radiopharmaceutical can potentially do for patients,” said Christian Behrenbruch, group CEO of Teryx, in a release this morning. “We are well-positioned to work toward our common goal of advancing the next generation of precision radiopharmaceuticals for patients with difficult-to-treat cancers.”
