Lantheus Holdings Discloses 20.9% Stake in Radiopharm Theranostics via Three Private Placements
RADX is trading near its 52-week low of $2.044 (1.8% above the low) on light trading volume (0.1× avg).
Summary
Lantheus Holdings disclosed a 20.9% beneficial ownership stake in Radiopharm Theranostics, built through three private placements totaling US$15 million between 2024 and 2025, including options to purchase 255 million additional shares.
Key Events · Ownership and Investor Activity · RADX
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Lantheus Discloses 20.9% Ownership Stake
Lantheus Holdings and subsidiaries report beneficial ownership of 792,958,513 ordinary shares, representing 20.9% of Radiopharm Theranostics' outstanding shares as of July 27, 2026.
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Three Private Placements Total US$15M
Lantheus Omega invested US$5 million in each of three placements: 149.6M shares at A$0.05 (Aug 2024), 133.3M shares at A$0.06 (Jan 2025), and 255M shares at A$0.03 plus 255M options (Dec 2025).
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Options Add Potential Future Dilution
Lantheus holds options to purchase 255,000,000 additional ordinary shares at A$0.039 per share, expiring October 31, 2027. If exercised, this would increase its stake beyond 20.9%.
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Strategic Investment Tied to Asset Purchase
The investment is connected to a June 2024 Purchase and Development Agreement under which Lantheus acquired rights to two preclinical radiopharmaceutical assets for a US$2 million upfront payment plus milestone and royalty obligations.
Analysis · RADX · Life Sciences
Lantheus Holdings, through its wholly-owned subsidiary Lantheus Omega, has accumulated a 20.9% beneficial ownership stake in Radiopharm Theranostics through three separate private placements totaling US$15 million. The stake includes 537.9 million ordinary shares and options to purchase an additional 255 million shares at A$0.039 each. This is the first public disclosure of the full ownership position, which was built between August 2024 and December 2025. The strategic investment is tied to a June 2024 Purchase and Development Agreement under which Lantheus acquired rights to two preclinical radiopharmaceutical assets. For Radiopharm, which reported a going-concern warning and only A$4.14 million in cash on August 28, 2026, the presence of a well-capitalized strategic investor with deep radiopharmaceutical expertise is a meaningful validation, though the 20.9% stake also represents significant potential future selling pressure if Lantheus decides to exit.
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At the time of this filing, RADX was trading at $2.08 on NASDAQ in the Life Sciences sector, with a market capitalization of approximately $31.2M. The 52-week trading range was $2.04 to $16.25. This filing was assessed with neutral market sentiment and an importance score of 7 out of 10.