Radiopharm Theranostics (ASX: RAD) crashes 21.6% despite A$40m capital raise and clinical milestones

Radiopharm Theranostics Limited (ASX: RAD; Nasdaq: RADX) shares plunged 21.6% on October 20, 2025, closing at A$0.029 after the radiopharmaceutical developer announced a dual-capital raise alongside a suite of positive clinical trial updates across its oncology pipeline. The sudden share price drop came as the market reacted to the company’s A$35 million institutional placement and a follow-up A$5 million share purchase plan (SPP), both priced at a steep discount of A$0.03 per share. This dilution-driven selloff overshadowed several encouraging clinical milestones in solid tumor indications such as brain metastases, HER2-positive cancers, PD-L1-positive tumors, and pancreatic adenocarcinoma.

Despite the market’s initial reaction, Radiopharm Theranostics enters the final quarter of 2025 with a significantly extended funding runway, a deepening clinical pipeline, and the continued support of its most notable strategic investor, Lantheus Holdings, Inc., which increased its stake to 14.5% through a fresh A$7.6 million investment. The sell-off appears to reflect investor discomfort with near-term dilution rather than long-term platform viability, particularly as Radiopharm gears up for multiple trial readouts and a potential expansion of its monoclonal antibody program.

Why did Radiopharm raise A$40 million, and how will the proceeds be allocated?

Radiopharm Theranostics confirmed that it had secured firm commitments for a A$35 million placement through the issuance of approximately 1.167 billion new ordinary shares at A$0.03 per share. These shares were offered to a mix of new and existing institutional investors across Australia and overseas, including key participation from Lantheus Holdings. Investors will also receive one free attaching option per share, exercisable at A$0.039 and expiring on October 31, 2027. The attaching options, which will require shareholder approval at the upcoming Extraordinary General Meeting in December 2025, are expected to be quoted on the ASX following the approval process.

In parallel, Radiopharm launched a share purchase plan to raise up to A$5 million from eligible shareholders in Australia and New Zealand. The SPP is structured on identical terms to the placement, including the option entitlement, and allows retail investors to apply for parcels of up to A$30,000 without incurring brokerage or transaction fees. While the targeted raise is A$5 million, the company has retained flexibility to increase or scale down the offer size based on demand.

In terms of allocation, Radiopharm has earmarked A$6 million for drug manufacturing, A$34 million for ongoing and upcoming clinical trials, and approximately A$19 million for general working capital, administrative overheads, and costs associated with the capital raise. Combined with the company’s existing cash balance of A$19 million as of September 30, 2025, the total funding pool extends Radiopharm’s operational runway into 2027.

What clinical developments did Radiopharm announce and how are they shaping investor expectations?

Alongside the capital raise, Radiopharm released a comprehensive clinical update showcasing progress across four core programs—each targeting difficult-to-treat solid tumors using radiopharmaceutical technologies. The announcements reflected early signs of efficacy, safety, and next-phase readiness across various trial stages.

The lead diagnostic candidate, RAD 101, is a small molecule radiolabeled with Fluorine-18, designed to target fatty acid synthase (FASN) in brain metastases. Interim data from the Phase 2b imaging trial in the United States showed clear uptake in metastatic lesions across the first three patients, confirming proof-of-concept and laying the groundwork for a global Phase 3 trial in 2026. Enrollment now stands at 12 out of 30 patients, with top-line data expected in the first half of 2026. The molecule already holds Fast Track Designation from the U.S. Food and Drug Administration.

In the therapeutic space, RAD 202, a nanobody targeting HER2 and radiolabeled with Lutetium-177, continues to generate encouraging signals in the Phase 1 HEAT trial. The first three patients dosed at the 30 mCi level demonstrated strong tumor uptake and favorable biodistribution without any drug-related adverse events. The Data Safety and Monitoring Committee has recommended escalation to the 75 mCi dose level. The company anticipates completing Cohort 2 by year-end, with full data from both cohorts also expected before the close of 2025.

Meanwhile, RAD 204, a PD-L1-targeting therapeutic using the same Lutetium-177 backbone, reported early evidence of clinical activity in difficult-to-treat cancers such as non-small cell lung cancer (NSCLC) and triple-negative breast cancer (TNBC). Two out of three NSCLC patients in the first cohort showed stable disease for 5.5 months, outperforming standard-of-care benchmarks. Six patients have been dosed across two cohorts, and safety data remains favorable, with no dose-limiting toxicities reported. A decision on dose escalation to the third level is pending.

The fourth active program, RAD 301, is a Gallium-68 labeled imaging agent targeting αvβ6 integrin, a marker associated with aggressive pancreatic cancer. Six out of nine planned patients have been dosed in the ongoing Phase 1 trial for metastatic disease, and initial imaging has confirmed uptake in αvβ6-positive lesions. Based on this data, Radiopharm intends to initiate a Phase 2 imaging trial in loco-regional pancreatic cancer patients, where earlier detection could enable more timely intervention and better surgical outcomes.

Beyond these core trials, Radiopharm’s pipeline also includes two preclinical monoclonal antibody assets—RV01 and RAD402—which are expected to enter Phase 1 trials by the end of 2025. This would bring the company’s active portfolio to six clinical-stage programs, a notable breadth for a firm still in its early commercialization timeline.

How are markets and institutional investors interpreting Radiopharm’s latest moves?

The immediate market reaction to Radiopharm’s announcements was distinctly negative, with shares falling by 21.6% and closing at a near-term low of A$0.029. The placement pricing, which carried a 19% discount to the last closing price and an 11.8% discount to the 15-day VWAP, likely spooked retail investors already wary of dilution. Trading volume surged to over 22 million shares, suggesting high turnover among short-term holders or profit-takers.

Yet institutional sentiment tells a more nuanced story. Lantheus’s decision to add A$7.6 million (approximately US$5 million) to its position speaks to a longer-term conviction in Radiopharm’s pipeline and platform strategy. Bell Potter Securities Limited acted as lead manager for the placement, with Leerink Partners and B. Riley Securities serving as U.S. placement agents—another signal that Radiopharm is now firmly attracting global biotech capital flows.

The company’s ability to raise A$40 million, in a sector where small-cap biotech funding has grown increasingly selective, reinforces its relative strength as a mid-tier clinical-stage player. The attaching options, which carry a 30% upside to the placement price, may further incentivize existing and new shareholders to maintain positions over the medium term.

What are the key clinical, financial, and regulatory milestones Radiopharm investors should watch through 2026?

Looking ahead, Radiopharm has outlined several key clinical and corporate milestones that could materially shift investor sentiment. Most notable among them are the Phase 2b top-line results for RAD 101 in brain metastases, and cohort results for RAD 202 and RAD 204 by the end of this year. The potential initiation of Phase 1 trials for RV01 and RAD402 by December 2025 will also serve as important indicators of pipeline breadth and R&D execution capability.

On the corporate side, the Extraordinary General Meeting scheduled for December 4, 2025, will be pivotal. Approval for the second tranche of the placement and the attaching options could clear the path for further fundraising flexibility and option liquidity on the ASX.

Investors will also be closely watching Radiopharm’s ability to secure partnerships, licensing agreements, or non-dilutive capital, which remain key value-unlocking levers for clinical-stage biotech companies heading into later-phase trials.

Key takeaways: Why Radiopharm Theranostics is still worth watching despite the steep sell-off

• Radiopharm Theranostics completed a heavily discounted A$35 million institutional placement and launched a A$5 million share purchase plan, sparking a 21.6 percent share price drop as investors reacted to dilution concerns.

• Strategic investor Lantheus Holdings Inc. deepened its position with a A$7.6 million commitment, lifting its stake to 14.5 percent and signaling continued institutional confidence in Radiopharm’s long‑term platform strategy.

• The raise extends Radiopharm’s funding runway through 2027, allocating A$34 million to clinical trials, A$6 million to manufacturing, and A$19 million to working capital and corporate expenses.

• Positive interim data were reported across four oncology programs — targeting brain metastases, HER2‑positive tumors, PD‑L1‑positive cancers, and pancreatic adenocarcinoma — each showing favorable safety and tumor‑uptake signals.

• Retail shareholders can participate in the share purchase plan on the same A$0.03 pricing as the placement, with free attaching options exercisable at A$0.039 until October 2027.

• The Extraordinary General Meeting on December 4, 2025 will be a key inflection point for shareholder approval of the second placement tranche and attaching‑option issuance.

• Despite short‑term volatility, Radiopharm’s expanding six‑program pipeline, institutional backing, and near‑term clinical catalysts position it as a small‑cap biotech to watch through 2026.