A Phase 1 interventional study of ATO-101™ in Bladder Cancer, sponsored by Institut Cancerologie de l'Ouest. Not yet recruiting at 1 site in France. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-06-08.
Sponsored by Institut Cancerologie de l'Ouest · Phase 1, Interventional, and Treatment
Non-Muscle-Invasive Bladder cancer (NMIBC) tumours often recur despite TransUrethral Resection of Bladder (TURB) and Bacillus Calmette-Guerin (BCG) intravesical instillations, and have no effective conservative treatment options. Alpha emitters like Astatine-211 (211At), due to their short path and short half-life, show promise for superficial targets such as NMIBC.
Carbonic anhydrase IX (CAIX), overexpressed in 70-90% of NMIBC cases but absent in healthy tissues, is an ideal target.
A clinical feasibility Positron emission tomography-computed tomography (PET/CT) imaging study (Pertinence, NCT04897763) was conducted at Institut de cancérologie Ouest (ICO) in six patients using Girentuximab labelled with Zirconium-89 ([89Zr]Zr-girentuximab). It demonstrated successful tracer targeting and no radioactive leakage beyond the bladder following intravesical instillation. The study also confirmed the absence of toxicity, contamination, or significant additional staff radiation exposure.
ATO-101™ ([²¹¹At]At-girentuximab) could enable localised tumour destruction while preserving the bladder in patients with BCG-unresponsive NMIBC. The ongoing First In Human (FIH) study evaluate the safety of ATO-101™ in patients with BCG-unresponsive NMIBC.
294 studies on the registry are indexed under Non-Muscle Invasive Bladder Neoplasms; 126 are open to participants now.
This study's planned enrollment of 24 is below the median of 62 across 231 interventional studies indexed under Non-Muscle Invasive Bladder Neoplasms.
Browse Non-Muscle Invasive Bladder Neoplasms studies →Institut Cancerologie de l'Ouest is the lead sponsor of 109 studies on the registry; 20 are open to participants now.
Compared within Non-Muscle Invasive Bladder Neoplasms, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Urinary Bladder Neoplasms. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
\[211At\]At-Girentuximab (ATO-101™) intravesical administration
Drug: ATO-101™
The study drug: \[211At\]At-Girentuximab (ATO-101™) is administered via intravesical instillation
Also known as: [211At]At-Girentuximab
To determine the Maximum Tolerated Dose (MTD) of ATO-101™.
The primary endpoint is the occurrence of dose-limiting toxicities (DLTs) during the DLT observation period.
Time frame: 15 days
To determine the Recommended Dose for Expansion (RDE) of ATO-101™.
The primary endpoint is the occurrence of dose-limiting toxicities (DLTs) during the DLT observation period.
Time frame: 15 days
Start is estimated for Jan 2027; primary completion for Jan 2029, 24 months later.
Of 24 phase 1 interventional studies under Non-Muscle Invasive Bladder Neoplasms, half reached primary completion within 43 months of starting (the median), counting those still running; a quarter within 19 and three quarters within 61. This study's planned 24 months is below that.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Dec 2025. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Non-Muscle Invasive Bladder Neoplasms →
Institut Cancerologie de l'Ouest →