for people ages 18 years and up (full criteria)
at Encinitas, California and other locations
study started
completion around
Principal Investigator
by Tyler M. Seibert
Headshot of Tyler M. Seibert
Tyler M. Seibert



This phase II trial tests whether the addition of radiation to the primary tumor, typically given with stereotactic ablative radiation therapy (SABR), in combination with standard of care immunotherapy improves outcomes in patients with renal cell cancer that is not recommended for surgery and has spread to other places in the body (metastatic). Radiation therapy uses high energy photons to kill tumor cells and shrink tumors. Stereotactic body radiation therapy uses special equipment to position a patient and deliver radiation to tumors with high precision. This method may kill tumor cells with fewer doses of radiation over a shorter period and cause less damage to normal tissue. Immunotherapy with monoclonal antibodies, such as nivolumab, ipilimumab, avelumab, and pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Axitinib, cabozantinib, and lenvatinib are in a class of medications called antiangiogenic agents. They work by stopping the formation of blood vessels that bring oxygen and nutrients to tumor. This may slow the growth and spread of tumor. Giving SABR in combination with standard of care immunotherapy may help shrink or stabilize the cancer in patients with renal cell cancer.

Official Title

Randomized Phase II Stereotactic Ablative Radiation Therapy (SABR) for Metastatic Unresected Renal Cell Carcinoma (RCC) Receiving Immunotherapy (SAMURAI)



  1. To determine whether the addition of stereotactic ablative radiotherapy (SABR) to the primary tumor in combination with immunotherapy improves outcomes compared to immunotherapy alone in patients with metastatic, unresected, renal cell carcinoma (RCC). The primary endpoint is nephrectomy and radiographic progression-free survival (nrPFS) with progression determined as per iRECIST criteria.


  1. To assess the safety, toxicity and tolerability of the two treatment strategies as defined by Common Terminology Criteria for Adverse Events (CTCAE) version 5 in each treatment arm.

II. To assess the objective response rate (ORR) by Immune-related Response Evaluation Criteria in Solid Tumors (iRECIST) in each treatment arm.

III. Nephrectomy and radiographic progression-free survival excluding nephrectomies that were performed for non-protocol specified indications (nephrectomy and radiographic progression-free survival [nrPFS]2).

IV. Radiographic progression-free survival (rPFS). V. To assess overall survival (OS) in each treatment arm. VI. To assess the time to subsequent second-line therapy or death in each treatment arm.

VII. To assess the rate of cytoreductive nephrectomy in each treatment arm. VIII. To assess treatment-free survival in patients who discontinue therapy for reason other than radiographic disease progression.

IX. To assess the ORR by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 and iRECIST in the primary renal mass.


  1. To assess composite nrPFS in the predefined histological subgroups below:

Ia. Clear cell versus non-clear cell histology. Ib. International Metastatic RCC database consortium (IMDC) intermediate versus poor risk group.

Ic. Systemic treatment with immunotherapy-immunotherapy combination versus immunotherapy-vascular endothelial growth factor (VEGF) targeted therapy combination.

Id. Sarcomatoid versus non sarcomatoid variant. II. To identify prognostic and predictive biomarkers of response to SABR in the context of immunotherapy based treatment via assessment of tissue and blood based biomarkers.

III. To evaluate the abscopal effect of SABR with systemic therapy. IIIa. Compare ORR in non-irradiated target lesions in the control arm patients undergoing immunotherapy alone to the experimental arm undergoing SABR + immunotherapy.

IV. To evaluate the impact of treatment on level of inferior vena cava (IVC) thrombus.

  1. To compare accruing center identified iRECIST progression and centrally identified iRECIST progression events on computed tomography (CT).

OUTLINE: Patients are randomized to 1 of 2 arms.

ARM I: Patients receive one of the following immunotherapy regimens per physician discretion: nivolumab intravenously (IV) over 30 minutes and ipilimumab IV over 30 minutes every 3 weeks for 4 doses followed by nivolumab IV over 30 minutes every 2 or 4 weeks; pembrolizumab IV over 30 minutes every 3 or 6 weeks and axitinib orally (PO) twice daily (BID); avelumab IV over 60 minutes every 2 weeks and axitinib PO BID; nivolumab IV over 30 minutes every 2 or 4 weeks and cabozantinib PO once daily (QD); OR pembrolizumab IV over 30 minutes every 3 or 6 weeks and lenvatinib PO QD. Treatment with immunotherapy continues in the absence of disease progression or unacceptable toxicity.

ARM II: Patients undergo SABR on 3 different days over 1-3 weeks and receive immunotherapy as in Arm I.

After completion of study treatment, patients are followed up every 6 months for 5 years, and then annually for 3 years.


Metastatic Renal Cell Carcinoma, Stage III Renal Cell Cancer AJCC v8, Stage IV Renal Cell Cancer AJCC v8, Unresectable Renal Cell Carcinoma, Carcinoma, Renal Cell Carcinoma, Pembrolizumab, Nivolumab, Ipilimumab, Avelumab, Lenvatinib, Axitinib, Monoclonal Antibodies, Cabozantinib, Stereotactic Ablative Radiotherapy


You can join if…

Open to people ages 18 years and up

  • Pathologically (histologically or cytologically) proven diagnosis of renal cell carcinoma prior to registration
  • Node-positive unresectable (TxN1Mx) or metastatic (TxNxM1) based on the following diagnostic workup:
    • History/physical examination within 45 days prior to registration
    • CT/magnetic resonance imaging (MRI) of the chest/abdomen/pelvis within 45 days prior to registration
  • Patients must have IMDC intermediate (1-2 factors) or poor risk disease (>= 3 factors)
  • Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial
  • Patients with measurable disease (node positive or metastatic) as defined by RECIST version 1.1 excluding the primary renal tumor
  • Patient not recommended for or refused immediate cytoreductive nephrectomy
  • Candidate for standard of care therapy with either immuno-oncology (IO)-IO or IO-VEGF combination regimen
  • Primary renal tumor measuring 20 cm or less in anterior to posterior dimension only on axial imaging
  • Age >= 18
  • Karnofsky performance status >= 60 within 45 days prior to registration
  • Hemoglobin >= 8 g/dL (transfusions are allowed) (within 45 days prior to registration)
  • Platelet count >= 50,000/mm3 (within 45 days prior to registration)
  • Absolute neutrophil count (ANC) >= 1500/mm3 (within 45 days prior to registration)
  • Calculated (Calc.) creatinine clearance >= 30 mL/min (within 45 days prior to registration)
    • For African American patients specifically whose renal function is not considered adequate by the formula above, an alternative formula that takes race into account (Chronic Kidney Disease Epidemiology Collaboration CKD-EPI formula) should be used for calculating the related estimated glomerular filtration rate (GFR) with a correction factor for African American race creatinine clearance for trial eligibility, where GFR >= 30 mL/min/1.73m2 will be considered adequate
  • Total bilirubin =< 1.5 x upper limit of normal (ULN) (except subjects with Gilbert Syndrome, who can have total bilirubin < 3.0 mg/dL) (within 45 days prior to registration)
  • Aspartate aminotransferase and alanine aminotransferase (AST and ALT) =< 3 x upper limit of normal (ULN) or < 5 x ULN if hepatic metastases present (within 45 days prior to registration)
  • Patients with known human immunodeficiency virus (HIV) on effective anti-retroviral therapy with undetectable viral load within 6 months are eligible for this trial. Testing is not required for entry into protocol
  • For patients with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable on suppressive therapy, if indicated
  • Patients with a history of hepatitis C virus (HCV) infection must have been treated and cured. Patients with HCV infection who are currently on treatment are eligible if they have an undetectable HCV viral load
  • The patient must agree to use a highly effective contraception, including men with vasectomies if they are having sex with a woman of childbearing potential or with a woman who is pregnant, while on study drug and for 6 months following the last dose of study drug. Childbearing potential is defined as any person who has experienced menarche and who has not undergone surgical sterilization (hysterectomy or bilateral oophorectomy) or who is not postmenopausal
  • The patient or a legally authorized representative must provide study-specific informed consent prior to study entry and, for patients treated in the United States (U.S.), authorization permitting release of personal health information

You CAN'T join if...

  • Patients with planned treatment of all metastatic disease with definitive therapy including either surgery, ablative (non-palliative) doses of radiation, or intervention of some type (definitive interventional radiology techniques) to ALL metastatic sites rendering the patient without extra-renal measurable disease. Patients NOT planned for definitive treatment of all metastatic sites are eligible. Lesions radiated palliatively are not eligible for response assessment
  • Patients with untreated or unstable brain metastases or cranial epidural disease
    • Note: Patients who have been adequately treated with radiotherapy, radiosurgery, or surgery and stable for at least 4 weeks prior to registration as documented by MRI or CT imaging or deemed stable by clinical investigator are eligible. Treated brain metastases are defined as having no ongoing requirement for steroids and no evidence of progression or hemorrhage after treatment for at least 4 weeks prior to registration as documented by MRI or CT imaging or deemed stable by clinical investigator
  • Prior radiotherapy to the kidney that would result in overlap of radiation therapy fields treatment of the primary tumor
  • Any systemic therapy for metastatic renal cell carcinoma (RCC) that was initiated > 90 days before registration, note that prior chemotherapy for a different cancer is allowed (completed > 3 years prior to registration)
  • Severe, active comorbidity defined as follows:
    • Active autoimmune disease requiring ongoing therapy including systemic treatment with corticosteroids (> 10 mg daily prednisone equivalents) or other immunosuppressive medications daily. Inhaled steroids and adrenal replacement steroid doses > 10 mg daily prednisone equivalents are permitted in the absence of active autoimmune disease
    • History of severe allergic, anaphylactic or other hypersensitivity reactions to chimeric or humanized antibodies
    • Active tuberculosis (purified protein derivative [PPD] response without active tuberculosis [TB] is allowed)
    • Uncontrolled hypertension (systolic blood pressure [BP] > 190 mmHg or diastolic BP > 110 mmHg)
    • Major surgery requiring hospital admission ≤ 28 days prior to registration.
    • Any serious (requiring hospital stay or long-term rehab) non-healing wound, ulcer, or bone fracture within 45 days prior to registration
    • Any arterial thrombotic (ST elevation myocardial infarction [STEMI], non-ST elevation myocardial infarction [NSTEMI], cerebrovascular accident [CVA], etc) events within 180 days prior to registration
    • Active New York (NY) Heart Association class 3-4 heart failure symptoms
    • Moderate or severe hepatic impairment (Child-Pugh B or C)
    • Any history of untreated pulmonary embolism or deep venous thrombosis (DVT) within 180 days prior to registration. (Any asymptomatic or treated pulmonary embolism or asymptomatic treated deep venous thrombosis > 30 days prior to registration is allowed)
    • Unstable cardiac arrhythmia within 180 days prior to registration
    • History of abdominal fistula, gastrointestinal perforation, intra-abdominal abscess, bowel obstruction, or gastric outlet obstruction within 180 days prior to registration
    • History of or active inflammatory bowel disease
    • Malabsorption syndrome within 45 days prior to registration
  • Pregnancy and individuals unwilling to discontinue nursing. For women of child bearing potential must have a negative pregnancy test =< 45 days prior to registration


  • UC San Diego Health System - Encinitas accepting new patients
    Encinitas California 92024 United States
  • UC San Diego Moores Cancer Center accepting new patients
    La Jolla California 92093 United States
  • UC San Diego Medical Center - Hillcrest accepting new patients
    San Diego California 92103 United States

Lead Scientist at UCSD

  • Tyler M. Seibert
    Dr. Seibert is a clinical translational researcher working on imaging and genetics for cancer detection and treatment. More at


accepting new patients
Start Date
Completion Date
NRG Oncology
Phase 2 research study
Study Type
Expecting 240 study participants
Last Updated