First human use of [177Lu]Lu-ABY-271 to target HER2-positive metastatic breast cancer

A First-in-Human Phase 1, Open-label, Two-stage, Randomized Trial to Assess the Safety, Tolerability, and Biodistribution of [177Lu]Lu-ABY-271 in Tumors and Critical Organs in Subjects With HER2-positive Metastatic Breast Cancer

Phase 1 Interventional Affibody · NCT07081555

This first-in-human Phase 1 test will see if the radiopharmaceutical [177Lu]Lu-ABY-271 is safe and how it distributes in the body for people with HER2-positive metastatic breast cancer.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment21 (estimated)
Ages18 Years and up
SexFemale
SponsorAffibody Industry-sponsored
Locations3 sites (Gothenburg and 2 other locations)
Trial IDNCT07081555 on ClinicalTrials.gov

What this trial studies

This open-label, first-in-human Phase 1 effort has two parts to characterize safety, tolerability, and biodistribution of [177Lu]Lu-ABY-271 in HER2-positive metastatic breast cancer. Part A will sequentially enroll up to six subjects to measure tumor and critical-organ uptake and early safety signals. Part B will randomize 15 subjects across three protein mass dose levels (1:1:1) in two sequential cohorts with different radioactivity levels to identify an optimal protein mass dose for later trials. Key eligibility includes confirmed HER2 overexpression, at least one lesion ≥15 mm, and ECOG performance status ≤2, with Part B restricted to patients with recent radiologic progression and at least three prior systemic lines.

Who should consider this trial

Good fit: Ideal candidates are adults with unresectable locally advanced or metastatic HER2-positive breast cancer, an ECOG ≤2 and at least one measurable lesion ≥15 mm, with Part B reserved for those with recent progression after ≥3 prior systemic therapies.

Not a fit: Patients with HER2-negative disease, active untreated brain metastases, poor performance status (ECOG >2), very small lesions, or ongoing significant toxicities from prior therapy are unlikely to benefit.

Why it matters

Potential benefit: If successful, this agent could deliver targeted radiation to HER2-positive tumors and potentially control disease while limiting exposure to healthy organs.

How similar studies have performed: Lutetium-177 targeted radiotherapies have proven effective in other cancers and early-phase HER2-targeted radiopharmaceutical and affibody imaging work has been promising, but [177Lu]Lu-ABY-271 is being tested in humans for the first time.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Subject has unresectable locally advanced or metastatic breast cancer
* Subject with histologically or cytologically confirmed carcinoma with documented HER2 overexpression (biopsy not older than 2 years): immunohistochemistry (IHC) score 3+; OR 2+ and fluorescence in situ hybridization (ISH) positive
* At least one known tumor lesion ≥ 15 mm
* Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2

Part A only

\- Subject is in treatment, or planned to start a new line of standard systemic anti-tumor therapy

Part B only

* Subject has progressive disease, documented radiologically in the last three months
* Subject has received at least 3 lines of standard systemic anti-tumor therapy in the palliative setting
* Subject has received last dose of previous line of systemic anti-tumor therapy, and has no ongoing treatment related toxicities \> grade 1 (except alopecia) prior to planned first dose of \[177Lu\]Lu-ABY-271

Exclusion Criteria:

* Active brain metastases
* Administration of another IMP within 5 half-lives (for experimental biologics: 6 months or 5 half-lives, whichever is longer) of the planned first dose of \[177Lu\]Lu-ABY-271
* Exposure to any anti-tumor therapy since the last documented progression, including any radiotherapy within 7 days prior to the planned first dose of \[177Lu\]Lu-ABY-271

Where this trial is running

Gothenburg and 2 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Metastatic Breast CancerHER2 + Breast CancerRadiopharmaceuticalBiodistributionFirst-in-humanphase 1safety
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.