Clinical trial NCT06824155: HEAT Trial (HER2 Antibody Therapy With Lutetium-177)
Official title: Phase 0/1 Study of the Safety and Tolerability of 177Lu-RAD202, a Lutetium-177 Radiolabeled Single Domain Antibody Against Human Epidermal Growth Factor Receptor 2 in Patients With Advanced Solid Tumours
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: EARLY_PHASE1
Conditions: HER2 Gene Mutation
Advanced Solid Tumors
Keywords: HER2 positive
Neoplastic disorder
Advanced solid tumors
Lead sponsor: Radiopharm Theranostics, Ltd
Sponsor class: INDUSTRY
First posted: 2025-02-13
Enrollment: 35
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: TREATMENT

Brief summary: This is a first-in-human, Phase 0/1, open-label study of177Lu-RAD202 consisting of an Imaging Period with 177Lu-RAD202im(imaging dose) and a Treatment Period with 177Lu-RAD202tr(treatment dose) to determine the recommended dose(s) for future exploration of 177Lu-RAD202 in participants with HER2 expressing advanced solid tumours.

Detailed description: This is a first-in-human, Phase 0/1, open-label study of 177Lu-RAD202 consisting of an Imaging Period with 177Lu-RAD202im (imaging dose) and a Treatment Period with 177Lu-RAD202tr (treatment dose) to determine the recommended dose(s) for future exploration of 177Lu-RAD202 in participants with HER2 expressing advanced solid tumours.

Screening Period: Screening period of up to 4 weeks Phase 0 (Imaging Period): Low dose 177Lu-RAD202 (starting at 10mCi) administered on Day 1 with a follow-up period of 2 weeks to assess imaging, safety and dosimetry. Following assessment of the imaging, safety and dosimetry results of the first 3 to 6 participants dosed with 177Lu-RAD202im (10mCi) the dose may be increased in subsequent participants, if needed, to improve image quality. Prior to determining the recommended dose level of 177Lu-RAD202im for future exploration, there is a minimum of 2 weeks between administration of 177Lu-RAD202im in Phase 0 and 177Lu-RAD202tr in Phase I. Following the dose determination for imaging, the timeframe can be reduced to \< 2 weeks by the Sponsor based on emergent safety and imaging quality data.

Phase I (Treatment Period): 177Lu-RAD202tr dose escalation

* Treatment Period of up to 3 cycles every 6 weeks. Extension of the planned dose intervals are possible following discussion and agreement between the Sponsor and Investigator. After the first 3 cycles, additional cycles may be evaluated following review and approval by the Sponsor and Investigator, depending on emergent safety, dosimetry, image quality, clinical activity and pharmacokinetic data.
* DLT observation period for 177Lu-RAD202tr is 6 weeks following first injection of 177Lu-RAD202tr.
* Should an alternative treatment schedule be explored, the DLT observation period for 177Lu-RAD202tr at that dose level will be the proposed cycle duration.

Eligibility criteria: Inclusion Criteria:

1. Aged 18 years and older.
2. Written, voluntary, informed consent of the participants must be obtained in compliance with institutional, regional, and federal guidelines.
3. Participants with histologically or cytologically confirmed, HER2 positive advanced solid tumours that are relapsed/refractory, locally advanced not amenable to curative-intent therapy, or metastatic, with documented disease progression during or after their most recent line of anti-cancer therapy. Participants must be refractory to or intolerant of standard of care therapy or have no standard of care therapy available that is likely to provide clinical benefit.

   Participant HER2 positivity is determined by local testing and is defined as a score of 3+ on immunohistochemical analysis IHC), or, defined as a score of 2+ on IHC and positive results on in situ hybridisation (ISH).
4. Must have at least 1 measurable target lesion according to RECIST version 1.1.
5. Eastern Cooperative Oncology Group (ECOG) performance status ≤2.
6. Participants must have a life expectancy of ≥4 months in the opinion of the Investigator.
7. Women of childbearing potential (WOCBP) must have a negative serum beta-human chorionic gonadotropin (β-hCG) test and must not be breastfeeding. WOCBP are defined as those who are not surgically sterile or post-menopausal. Female participants will be considered post-menopausal if they have been amenorrheic for 12 months without an alternative medical cause.
8. WOCBP must agree to use a highly effective method of contraception during the study and for 60 days after the last dose of 177Lu-RAD202 (60 days is approximately 10 physical half-lives of 177Lu and \>480 effective half-lives of NM-02DOTAGA). Acceptable methods of contraception are described in Section 12.3.3 of the Protocol.
9. Male participants who are able to father a child must agree to avoid impregnating a partner and to adhere to a highly effective method of contraception during the study and for 90 days after the last dose of 177Lu-RAD202. All male participants must agree to not donate sperm during the study and at least 14 days after the last injection of 177Lu-RAD202im and/or 90 days after the last dose of 177Lu-RAD202tr, whichever occurs later. Acceptable methods of contraception are described in Section 12.3.3 of the Protocol.
10. Participants with previously treated brain metastases are eligible to participate if:

    1. They are neurologically and radiologically stable (no evidence of progression by imaging; same imaging modality \[magnetic resonance imaging (MRI) or computed tomography (CT) scan\] must be used for each assessment),
    2. Do not require steroids to treat associated neurological symptoms, and
    3. Participants have no history of leptomeningeal disease or spinal
11. For Phase 1 (Treatment Period): Participants must have positive lesion(s) by 177Lu-RAD202im SPECT/CT per central review.

Exclusion Criteria:

1. Participants who have any other known, active malignancy, except for treated cervical intraepithelial neoplasia, or nonmelanoma skin cancer. Participants with a history of malignancies of low recurrence potential who have received curative-intent therapy may be approved on a case-by-case basis in discussion with the study Sponsor, if it is determined not to put the participant at an increased risk of adverse drug effects and/or interfere with the integrity of study outcome.
2. Participants who have any medical condition that would, in the Investigator's judgment, prevent the participant's full participation in the clinical study due to safety concerns or compliance with clinical study procedures such as participants with severe claustrophobia who are unresponsive to oral anxiolytics, participants with low back pain who cannot lie comfortably on an imaging table, participants who are hyperactive or hyperkinetic such that they cannot tolerate lying still for multiple time-point imaging procedures, etc.
3. Residual toxicity Grade ≥ 2 from previously administered therapy (except for alopecia).
4. Inadequate organ functions as reflected in laboratory parameters:

   * Creatinine clearance (calculated using Cockcroft-Gault formula, or measured) \< 60 mL/min
   * Platelet count of \< 100 x 109/L
   * Absolute neutrophil count (ANC) \< 1.5 x 109/L
   * Haemoglobin \< 9 g/dL
   * Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \> 3 x ULN, or \> 5 x ULN for patients with known liver metastases
   * Total bilirubin \> 1.5 x ULN, except for participants with documented Gilbert's syndrome who are eligible if total bilirubin ≤ 3 x ULN
   * For participants not taking warfarin or other anticoagulants: international normalised ratio (INR) ≤1.5 or prothrombin time (PT) ≤1.5 x ULN; and either partial thromboplastin time or activated partial thromboplastin time (PTT or aPTT) ≤1.5 x ULN. Participants taking warfarin must be on a stable dose that results in a stable INR \<3.5. Among participants receiving other anticoagulant therapy, PT or aPTT must be within the intended therapeutic range of the anticoagulant.
5. Significant cardiovascular disease including:

   * Unstable angina and/or myocardial infarction within 6 months prior to screening
   * New York Heart Association Class II or greater congestive heart failure
   * Clinically significant abnormalities in rhythm, conduction, or morphology of resting ECG (e.g., complete left bundle branch block, third degree heart block)
   * QTcF \> 470 msec for females and QTcF \> 450 msec for males on screening electrocardiogram (ECG) or congenital long QT syndrome
   * Uncontrolled hypertension
   * Known LVEF \< 50%
6. History of uncontrolled allergic reactions and/or have hypersensitivity to anti-HER2 monoclonal antibodies, kanamycin A or aminoglycoside therapies, or other excipients that may induce hypersensitivity
7. Pregnant or lactating women
8. Participants who are receiving any other investigational agents

   The following exclusion criteria applies to participants in Phase 1 (Treatment Period):
9. Major surgery within 4 weeks prior to first dose of 177Lu-RAD202tr. Exceptions may be approved on a case-by-case basis in discussion with study Sponsor, if it is determined not to put the participant at an increased risk of adverse drug effects and/or interfere with the integrity of study outcome.
10. Received anti-cancer therapy, including chemotherapy, immunotherapy, radiation therapy, biologic, herbal therapy, or any investigational therapy or investigational device, within 28 days (or 5 half-lives for biologic/non-cytotoxic agents, whichever is shorter), prior to the first dose of 177Lu-RAD202tr.
11. Has had or is scheduled to have major surgery ≤28 days prior to the first dose of 177Lu-RAD202tr. Elective surgical procedures not considered to put participants at higher risk of AEs may be allowed on a case-by-case basis in discussion with the Sponsor.
12. Positive status for human immunodeficiency virus (HIV).
13. Active or chronic hepatitis B or C. Chronic hepatitis B or hepatitis C with undetectable viral loads on stable suppression therapy may be allowed on a case-by-case basis in discussion with study Sponsor.
14. Any medical condition which, in the opinion of the Investigator, places the participant at an unacceptably high risk for toxicities.
15. Any uncontrolled intercurrent illness or clinically significant uncontrolled condition(s), including but not limited to active bacterial, fungal, or viral infections requiring systemic therapy.

Primary outcomes:
measure: Time Activity Curves (TACs)
timeFrame: 72 hours
measure: Radiation dosimetry of Lu177-RAD202im
timeFrame: 72 hours
measure: Safety and tolerability of a single dose of 177Lu-RAD202tr
timeFrame: 6 weeks
measure: Recommended dose(s) of 177Lu-RAD202tr for future exploration
timeFrame: 6 weeks
measure: Pharmacokinetics of 177Lu-RAD202im
timeFrame: 72 hours
measure: Biokinetics of 177Lu-RAD202im
timeFrame: 72 hours
Secondary outcomes:
measure: Safety and tolerability of 177Lu-RAD202im
timeFrame: 6 weeks
measure: Recommended dose(s) of 177Lu-RAD202im for future exploration
timeFrame: 2 weeks
measure: Preliminary antitumor activity of 177Lu-RAD202tr
timeFrame: Up to 30 weeks
measure: Radiation dosimetry of 177Lu-RAD202tr
timeFrame: 72 hours
Other outcomes:
measure: Level of agreement between 177Lu-RAD202im and standard of care imaging
timeFrame: Up to 30 weeks
measure: Effect of 177Lu-RAD202im and 177Lu-RAD202tr on tumor markers
timeFrame: Up to 30 weeks
Locations:
city: Kingswood
country: Australia
facility: Nepean Hospital
state: New South Wales
city: Murdoch
country: Australia
facility: GenesisCare Murdoch
state: Western Australia
Study officials:
References: