Radiopharm Theranostics Presents Initial Findings from Phase 1 First-in-Human HEAT Clinical Trial for 177Lu-RAD202 in HER2+ Solid Tumors at American Association for Cancer Research 2026
Rhea-AI Summary
Radiopharm Theranostics (Nasdaq: RADX) reported initial Phase 0/1 HEAT trial findings for 177Lu-RAD202 on April 20, 2026. In three patients dosed at 30 mCi, the agent showed meaningful tumor uptake, mainly in breast lesions, was generally well tolerated (predominantly Grade 1–2 AEs), and had no dose-limiting toxicities.
The Data Safety and Monitoring Committee approved escalation to the third cohort at 130 mCi; organ dosimetry remained within expected, clinically acceptable ranges.
AI-generated analysis. Not financial advice.
Positive
- Meaningful tumor uptake at 30 mCi in treated patients
- No dose-limiting toxicities observed in initial cohort
- DSMC approved escalation to 130 mCi cohort
Negative
- Early data from only three patients, limiting statistical confidence
- Efficacy at therapeutic doses unproven until higher-dose cohorts report results
News Market Reaction – RADX
On the day this news was published, RADX gained 4.59%, reflecting a moderate positive market reaction.
Data tracked by StockTitan Argus on the day of publication.
Key Figures
Market Reality Check
Peers on Argus
RADX fell 1.29% while momentum peers like BRNS and BCAB were up 15.05% and 3.70%, respectively, suggesting stock-specific trading rather than a broad biotech move.
Previous Clinical trial Reports
| Date | Event | Sentiment | Move | Catalyst |
|---|---|---|---|---|
| Apr 08 | Dose escalation update | Positive | +3.0% | DSMC cleared 177Lu-RAD202 dose escalation to 130mCi in HEAT trial. |
| Mar 27 | First patient dosed | Positive | +0.0% | Initiated Phase 1 trial of RAD 402 in advanced prostate cancer. |
| Mar 24 | Interim imaging data | Positive | -10.8% | RAD 101 achieved 90% PET–MRI concordance in Phase 2b brain metastases. |
| Feb 24 | First-in-human trial | Positive | +1.8% | Dosed first patient in Phase 1/2a trial of 177Lu‑BetaBart (RV‑01). |
| Dec 15 | Interim endpoint met | Positive | +149.5% | RAD 101 interim data showed 92% primary endpoint achievement in Phase 2b. |
Clinical trial headlines have often led to sizeable but mixed price reactions, with both strong rallies and sharp selloffs.
Over the last few months Radiopharm Theranostics has delivered multiple clinical updates across its pipeline. RAD 101 imaging data in brain metastases showed high PET–MRI concordance on Mar 24, 2026, yet shares fell 10.78%. First-patient dosing in the RAD 402 prostate cancer trial on Mar 27, 2026 saw no move, while advancing 177Lu-RAD202 to 130mCi (Cohort 3) on Apr 8, 2026 produced a 2.99% gain. Earlier, BetaBart (RV‑01) and RAD 101 interim data in 2025 triggered modest and very large positive moves, respectively. Today’s HEAT trial update fits this pattern of binary reactions to clinical progress.
Historical Comparison
Past clinical-trial headlines for RADX averaged a 28.71% move, while today’s HEAT trial update coincides with a 1.29% decline, making this reaction relatively muted versus history.
Clinical news flow shows a broad pipeline advancing: RAD 101 progressing through Phase 2b, 177Lu-RAD202 escalating doses in HEAT, RAD 402 starting Phase 1 in prostate cancer, and BetaBart (RV‑01) entering first-in-human Phase 1/2a.
Regulatory & Risk Context
An effective Form F-3 dated Dec 17, 2025 registers resale of up to 940,000 ADSs (281,999,998 ordinary shares) for existing holders. Proceeds from any ADS sales go to selling shareholders; the company receives cash only if associated options are exercised. The shelf remains active through Dec 17, 2028 and shows 0 recorded usages in the provided data.
Market Pulse Summary
This announcement provides first-in-human safety, biodistribution and tumor-uptake data for 177Lu‑RAD202 in the HEAT trial, with meaningful uptake at 30 mCi and mostly Grade 1–2 adverse events in three heavily pre-treated patients. It follows earlier clinical progress across RAD 101, RAD 402 and BetaBart programs. Investors may focus on upcoming higher-dose cohorts at 130 mCi, future efficacy signals, and how ongoing trial costs interact with the company’s existing F‑3 shelf and capital resources.
Key Terms
phase 0/1 medical
radiopharmaceutical medical
her2 medical
data safety and monitoring committee medical
biodistribution medical
dosimetry medical
treatment-emergent adverse events medical
dose-limiting toxicities medical
AI-generated analysis. Not financial advice.
177Lu-RAD202 demonstrated encouraging tumor uptake and a favorable safety profile in the lowest dose cohort
Data Safety and Monitoring Committee Recently Approved Advancing 177Lu-RAD202 to Next Highest Dose at 130 mCi
SYDNEY, April 20, 2026 (GLOBE NEWSWIRE) -- Radiopharm Theranostics (ASX: RAD, Nasdaq: RADX, “Radiopharm” or the “Company”), a clinical-stage biopharmaceutical company focused on developing innovative oncology radiopharmaceuticals for areas of high unmet medical need, today announced that new data from the ongoing Phase 0/1 HEAT trial (NCT06824155), evaluating 177Lu-RAD202, a first-in-class HER2-targeted radiopharmaceutical therapy, will be presented as a poster at the American Association for Cancer Research (AACR) Annual Meeting 2026, being held April 17–22, 2026 in San Diego, California.
“These first-in-human results represent an important early milestone for our HER2-targeted radiopharmaceutical program,” said Dr. Dimitris Voliotis, Chief Medical Officer of Radiopharm Theranostics. “In a heavily pre-treated patient population with significant unmet need, 177Lu-RAD202 demonstrated encouraging tumor uptake and a favorable safety profile at the lowest dose level. Importantly, the observed dosimetry supports continued dose escalation, which was recently approved by the Data Safety and Monitoring Committee (DSMC) to advance to the third cohort at 130 mCi dosing. We look forward to further evaluating the therapeutic potential of this novel approach and expect to see signs of antitumor activity at higher, more therapeutic dose levels.”
The AACR poster highlights first-in-human safety, biodistribution, dosimetry and tumor uptake clinical findings from the initial lowest dose cohort of three patients with advanced HER2-positive breast and urothelial cancers who had received multiple prior metastatic therapies and were dosed at 30 mCi.
Key Findings from the AACR Abstract and Poster
- Meaningful tumor uptake of 177Lu-RAD202 was observed at the initial and lowest dose level of 30 mCi, particularly in breast cancer lesions
- 177Lu-RAD202 was generally well tolerated in the first three treated patients, with predominantly Grade 1–2 treatment-emergent adverse events
- No dose-limiting toxicities or treatment discontinuations due to adverse events were observed
- Organ-level absorbed radiation doses were within expected and clinically acceptable ranges, supporting continued dose escalation
Poster Presentation Details
- Title: A First-in-Class HER2-Targeted Radiopharmaceutical Therapy: Initial Findings from the Phase 0/1 HEAT Trial of 177Lu-RAD202 in HER2+ Advanced Solid Tumors
- Abstract Number: CT046
- Presenter: Dimitris Voliotis, M.D., Chief Medical Officer of Radiopharm Theranostics
- Session: Poster Session
- Dates: April 20, 2026 at 9:00 AM PT
The complete poster can be found on the Company’s website here.
On April 8, 2026, Radiopharm Theranostics announced the positive recommendation from the Data Safety and Monitoring Committee (DSMC) to advance 177Lu-RAD202 to the third cohort at a dose level of 130mCi in the Phase 1 ‘HEAT’ clinical trial in patients with HER2-positive advanced solid tumors1. The DSMC is a multidisciplinary committee that conducts detailed reviews of study data, discusses potential safety events and provides recommendations regarding trial continuation.
About the HEAT Trial
177Lu-RAD202 is a Lutetium-177–labeled single-domain antibody (sdAb) designed to target HER2-expressing tumors. The sdAb format enables deep tumor penetration and rapid systemic clearance, while the beta-emitting isotope 177Lu delivers cytotoxic radiation with potential bystander effects independent of HER2 receptor density.
The HEAT trial (HER2-Antibody Therapy with Lutetium-177; (NCT06824155) is a first-in-human, open-label, multicenter integrated Phase 0/1 study evaluating 177Lu-RAD202 in patients with HER2-positive locally-advanced or metastatic solid tumors.
- Phase 0 evaluates biodistribution, pharmacokinetics, and radiation dosimetry using an imaging dose
- Phase 1 consists of multiple-dose escalation to assess safety, tolerability, tumor targeting, and to determine the recommended Phase 2 dose
About RAD202:
RAD202 is a proprietary single-domain monoclonal antibody (sdAb) that targets the Human Epidermal Growth Factor Receptor 2 (HER2)-positive expression in advanced solid tumors. HER2 is overexpressed in breast cancer and several other solid tumors and represents a validated target in oncology. In a previous diagnostic study of ten HER2-positive breast cancer patients, RAD202 demonstrated clinical proof-of-concept and had positive safety and biodistribution2,3.
About Radiopharm Theranostics
Radiopharm Theranostics is a clinical stage radiotherapeutics company developing a world-class platform of innovative radiopharmaceutical products for diagnostic and therapeutic applications in areas of high unmet medical need. Radiopharm is listed on ASX (RAD) and on NASDAQ (RADX). The company has a pipeline of distinct and highly differentiated platform technologies spanning peptides, small molecules and monoclonal antibodies for use in cancer. The clinical program includes one Phase 2 and five Phase 1 trials in a variety of solid tumor cancers including lung, breast, prostate and brain. Learn more at radiopharmtheranostics.com.
Authorized on behalf of the Radiopharm Theranostics Board of Directors by Executive Chairman Paul Hopper.
For more information:
Investors:
Riccardo Canevari
CEO & Managing Director
P: +1 862 309 0293
E: rc@radiopharmtheranostics.com
Anne Marie Fields
Precision AQ (formerly Stern IR)
E: annemarie.fields@precisionaq.com
Media:
Matt Wright
NWR Communications
P: +61 451 896 420
E: matt@nwrcommunications.com.au
Follow Radiopharm Theranostics:
Website – https://radiopharmtheranostics.com/
X – https://x.com/TeamRadiopharm
LinkedIn – https://www.linkedin.com/company/radiopharm-theranostics/
InvestorHub – https://investorhub.radiopharmtheranostics.com/
1 clinicaltrials.gov/study/NCT06824155
2 Zhao et al, Br Canc Res (2024)
3 Zhao et al, Mol Pharmaceut (2021)
