RYZ401 for solid tumors that express somatostatin receptors

Phase 1 First-in-Human, Dose Escalation and Dose Expansion Study of RYZ401, a Novel Radiopharmaceutical Therapy Labeled With Actinium-225, in Subjects With Neuroendocrine Tumors and Other Solid Tumors Expressing Somatostatin Receptors.

Phase 1 Interventional RayzeBio, Inc. · NCT07165132

This trial will try RYZ401, a targeted radiotherapy, in adults with neuroendocrine or other solid tumors that show somatostatin receptors to find a safe dose and see if it shrinks tumors.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment104 (estimated)
Ages18 Years and up
SexAll
SponsorRayzeBio, Inc. Industry-sponsored
Locations4 sites (Iowa City, Iowa and 3 other locations)
Trial IDNCT07165132 on ClinicalTrials.gov

What this trial studies

This is a Phase 1, open-label dose-escalation and dose-expansion trial of RYZ401 in adults with SSTR-positive neuroendocrine tumors (NETs) and selected other solid tumors. The dose-escalation phase seeks the recommended Phase 2 dose (RP2D) and optimal regimen, followed by expansion cohorts focused on GEP-NETs and other frequently SSTR-expressing indications. Key endpoints include safety, tolerability, and preliminary anti-tumor activity, with eligibility confirmed by SSTR-PET imaging and requirements for adequate organ function. Patients who previously received peptide receptor radionuclide therapy such as lutetium-177 are excluded.

Who should consider this trial

Good fit: Adults (≥18) with histologically confirmed well-differentiated (Grade 1–3) metastatic or unresectable NETs or other SSTR-positive solid tumors, measurable disease on SSTR-PET, and adequate renal, hepatic, and hematologic function are the intended candidates.

Not a fit: Patients whose tumors lack SSTR expression, those with prior peptide receptor radionuclide therapy such as Lu-177, or those with inadequate organ function are unlikely to benefit from this trial.

Why it matters

Potential benefit: If successful, RYZ401 could offer a new targeted radiotherapy option that shrinks or stabilizes SSTR-positive NETs while maintaining a manageable safety profile.

How similar studies have performed: Related SSTR-targeted radiotherapies, most notably 177Lu-DOTATATE, have shown clinical benefit in GEP-NETs, so this approach builds on established radioligand therapy while testing a different agent.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion criteria:

* At least 18 years old at the time of signing the main study informed consent form (ICF).
* Histologically confirmed:

Dose Escalation (all cohorts): Grades 1-3 WD, metastatic or locally advanced and unresectable NET at any primary site, including, but not limited to, GI, pancreatic, lung, thyroid, breast, urogenital, and adrenal tumors.

* Dose Expansion Cohort A: Grades 1-3 WD, metastatic or locally advanced and unresectable GEP-NETs
* Dose Expansion Cohort B: metastatic or locally advanced and unresectable tumors known to frequently express SSTR, limited to the following indications:

  * WD NETs (Grades 1-3) from primary sites other than gastrointestinal and pancreatic (including, but not limited to, lung, thyroid, breast, urogenital, and adrenal tumors) Meningioma (Grades 1-3)

    * SSTR-positive disease, as assessed by SSTR-PET imaging
    * Adequate renal, hematologic and hepatic function

Exclusion criteria:

* Prior RPT, including Lu-177.
* Prior solid organ or bone marrow transplantation.
* Use of chronic systemic steroid therapy.
* Significant cardiovascular disease
* Resistant hypertension
* Uncontrolled diabetes
* Prior history of liver cirrhosis
* HIV, hepatitis B infection or known active hepatitis C virus infection.

Note: Additional criteria may apply and will be assessed by the study site

Where this trial is running

Iowa City, Iowa and 3 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 GEP-NETGastroenteropancreatic Neuroendocrine TumorGastroenteropancreatic Neuroendocrine Tumor DiseaseNeuroendocrine TumorsCarcinoidCarcinoid TumorPancreatic NETSolid Tumor
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.