A Dose Escalation and Dose Optimization Phase 1A/1B Study to Evaluate Safety, Tolerability and Dosimetry of Radioligand Therapy with Ly4337713 in Adults with Fap-Positive Solid Tumors (Firebolt)

Study of Investigational Medicine for FAP-Positive Solid Tumors

M
Mateusz Opyrchal, MD, PhD

Primary Investigator

Recruiting
18 years - 100 years
All
Phase N/A
3 participants needed
1 Location

Brief description of study

This is a study of LY4337713 in participants with certain types of cancer that is advanced or has spread. Participants must have cancer with high levels of a protein called fibroblast activation protein (FAP). The purpose of this study is to evaluate safety, side effects, and efficacy of LY4337713. In addition, this study will evaluate how much LY4337713 gets into the bloodstream, how it is broken down, and how long it takes the body to get rid of it. 

Interested in participating? For more information about this research study or other cancer-related clinical trials at IU Simon Comprehensive Cancer Center, please contact:

IU Clinical Trials Office 
Phone: (317) 278-5632

Detailed description of study

Phase 1a (Escalation) 
Primary: To assess the safety and tolerability of LY4337713. Secondary: To assess the biodistribution and radiation dosimetry of LY4337713 to normal organs. To characterize the PK properties of LY4337713. To assess preliminary antitumor activity of LY4337713.

Phase 1a (Optimization) 
Primary: To determine the optimal dose and schedule of LY4337713. Secondary: To assess preliminary antitumor activity of LY4337713.

Phase 1b (Expansion) 
Primary: To assess, for each dose expansion cohort, the antitumor activity of LY4337713. Secondary: To assess the safety and tolerability of LY4337713. To assess, for each dose expansion cohort, the antitumor activity of LY4337713

For each participant, the study will last about 5 years.

Eligibility of study

You may be eligible for this study if you meet the following criteria:

  • Conditions: Fap-Positive Solid Tumors, Cancer
  • Age: 18 years - 100 years
  • Gender: All

Inclusion Criteria:

  • Must have clinical or imaging evidence of fibroblast activation protein (FAP) expression per local assessment
  • Must have histologically or cytologically confirmed diagnosis of one of the following:
    • Adenocarcinoma of the pancreas
    • Hormone receptor (HR)-positive human epidermal growth factor 2 (HER2)-negative breast cancer
    • HER2-positive breast cancer
    • Triple negative breast cancer (TNBC)
    • Platinum-resistant or refractory ovarian cancer
    • Other solid tumors
      • Gastric cancer (adenocarcinoma)
      • Colorectal cancer (CRC)
      • Esophageal cancer (squamous cell carcinoma or adenocarcinoma)
      • Cholangiocarcinoma
  • Must have received prior treatments as indicated below:
    • Phase 1a
      • Adenocarcinoma of the pancreas: Participants must have progressed after at least 1, but no more than 2 prior regimens for locally advanced unresectable or metastatic disease.
      • HR-positive HER2-negative breast cancer: Participants must have received less than or equal to (≤)5 prior lines of treatment for advanced or metastatic disease, which must include a cyclin-dependent kinase 4/6 inhibitor.
      • HER2-positive breast cancer: Participants must have progressed on at least 2 lines of HER2-targeted therapy, which should include at least 1 antibody-drug conjugate (ADC) for metastatic disease (if locally available).
      • TNBC: Participants must have progressed on at least 2 lines of therapy for metastatic disease.
      • Platinum-resistant or refractory ovarian cancer: Participants must have progressed on or after at least 1 platinum-based therapy.
      • Other solid tumors (gastric cancer, CRC, esophageal and cholangiocarcinoma): Participants must have received greater than or equal to (≥)1 prior line of systemic therapy for advanced or metastatic disease; including prior line(s) in combination with immunotherapy or vascular endothelial growth factor inhibitor.
    • Phase 1b:
      • Participants must have advanced or metastatic solid tumors and have received ≥1 prior line of therapy.
  • Must have an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 to 1.
  • Measured creatinine clearance ≥60 milliliters per minute (mL/min)

Exclusion Criteria:

  • Have known active central nervous system (CNS) metastases or carcinomatous meningitis.
  • Have history of Grade 4 myelosuppression lasting greater than (>)7 days, or Grade 3 myelosuppression requiring more than 6 weeks recovery.
  • Have significant cardiovascular disease
  • Have prolongation of the corrected QTcF >470 milliseconds (msec) during screening. QTcF is calculated using Fridericia's Formula: QTcF = QT/(RR0.33)
  • Have evidence of ongoing and untreated urinary tract obstruction
  • Had previous hemi- or total-body radiation.
  • Had previous adoptive T-cell therapy (e.g., chimeric antigen receptor T-cell [CAR-T therapy, T-cell receptor [TCR] therapy, etc.)
  • Unable to lie flat during, or otherwise tolerate, single photon emission computed tomography (SPECT), positron emission tomography (PET), computed tomography (CT) or magnetic resonance imaging (MRI).

This study investigates an investigational medicine for treating adults with advanced cancers that have high levels of a protein called fibroblast activation protein (FAP). The purpose of this study is to evaluate safety, side effects, and the amount of the investigational medicine that enters the bloodstream, how it is broken down, and how long it takes the body to clear it.

Participants will receive different doses to find the best and safest amount. The study will also check how the investigational medicine spreads in the body and its initial effects on tumors. Participants will undergo various tests and procedures to monitor these effects.

  • Who can participate: Adults with advanced or metastatic FAP-positive solid tumors, such as pancreatic, breast, ovarian, and other specified cancers, may participate. Participants must have received prior treatments and have a good performance status.
  • Study details: Participants will receive an investigational medicine and undergo tests to monitor safety and effects. Some participants may receive a placebo, which is an inactive substance that looks like the investigational medicine but does not contain any medicine.
  • Study timelines: The study will last about 5 years.
Updated on 30 Apr 2026. Study ID: CTO-J6K-OX-JSFA, 29429

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