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Gene-Modified Immune Cells (FH-MCVA2TCR) in Treating Patients with Metastatic or Unresectable Merkel Cell Cancer

Trial Status: Active

This phase I / II trial studies the side effects of gene-modified immune cells (FH-MCVA2TCR) and to see how well they work in treating patients with Merkel cell cancer that has spread to other parts of the body (metastatic) or that cannot be removed by surgery (unresectable). Placing a gene that has been created in the laboratory into immune cells may improve the body's ability to fight Merkel cell cancer.

Inclusion Criteria

  • Metastatic or unresectable Merkel cell polyomavirus (MCPyV)-associated Merkel cell carcinoma (VP-MCC) that has progressed on or after prior treatment with a PD-1 axis immune checkpoint inhibitor.
  • Individuals that may be consented to undergo evaluation to determine potential eligibility must have a history of metastatic or unresectable Merkel cell carcinoma (MCC) (as documented by medical record).
  • Be capable of understanding and providing informed consent.
  • Participants must have metastatic or unresectable, histologically confirmed virus-positive MCC. Confirmation of diagnosis must be or have been performed by internal pathology review of initial or subsequent biopsy or other pathologic material at Fred Hutch/Seattle Cancer Care Alliance (SCCA).
  • Approximately 80% of MCCs are caused by Merkel cell polyomavirus T Antigens and the treatment is expected to only be effective in this population. Merkel cell polyomavirus positivity may be established through one of two means: positive Merkel cell polyomavirus T antigen serology (preferred) or immunohistochemistry of a primary or metastatic MCC tumor lesion (if T antigen seronegative).
  • MCPyV T Antigen serology will be performed with the anti-Merkel cell panel (AMERK) assay run through the University of Washington Medical Center Laboratory Medicine Clinical Immunology Laboratory. Positivity will be defined as a Merkel oncoprotein antibody titer (MSCTT) of >= 75 standard titer units (STU) at any time point from initial diagnosis onward. Patients with negative T antigen serology but MCPyV positive tumor by other methodologies will be considered for additional MCPyV testing as clinically appropriate, as the T antigen serology assays are highly specific but incompletely sensitive for MCPyV status. In this case, immunohistochemistry of any tumor lesion will be performed with the CM2B4 Merkel cell polyomavirus T antigen antibody. Expression of MCPyV in at least 10% of tumor cells will be considered positive. CM2B4 staining performed at any point clinically and at any clinical laboratory may be accepted. However, if CM2B4 staining has not been previously performed by a clinical pathology laboratory as part of MCC diagnostic workup, it will be performed in a clinical diagnostic pathology laboratory at University of Washington (UW)/Fred Hutchinson Cancer Research Center (FHCRC)/SCCA as per standard staining protocols. Persons are not required to have both CM2B4 positivity and seropositivity; either will be acceptable confirmation of viral status and if one negative and the other positive the patient will remain eligible provided other criteria are met.
  • Measurable disease by RECIST 1.1, with at least two tumor lesions * Participants must have measurable disease, defined as at least one target lesion that can be measured in at least one dimension (longest diameter to be recorded) as >= 10 mm, unless lymph node in which case short axis must be >= 15 mm. For patients with bone-only metastases, bony lesions can only be selected as a target lesion if they have a measurable soft-tissue component. If a patient has only one measurable target lesion, they must have a second MCC lesion (bone lesion, smaller lesion, etc.) that is amenable to HLA upregulation (with single fraction radiation), in order to allow for efficacy assessments; this second lesion does not need to be measurable. Baseline imaging (for example computed tomography [CT] chest/abdomen/pelvis and imaging of the affected extremity as appropriate), and brain imaging (magnetic resonance imaging [MRI] or CT scan) must be obtained within 45 days of prior to start of first planned FH-MCVA2TCR infusion. Positron emission tomography (PET) CT or MRI can be substituted for CTs as appropriate.
  • Patients must have been previously treated with at least one dose of a PD-1 axis inhibitor (e.g. PD-1 or PD-L1 inhibiting monoclonal antibody such as pembrolizumab, nivolumab, avelumab, atezolizumab, durvalumab), developed progression of their MCC tumor on or after treatment, and not developed grade 3 or higher toxicity. At least four weeks must have passed between the administration of the first dose of PD-1 axis inhibitor and determination of progression. If there is significant clinical concern for pseudoprogression (i.e. progression developed rapidly after checkpoint inhibitor therapy), biopsy must be performed to demonstrate true progression. Patients may have received 1 or more prior systemic regimens for MCC. There is no upper limit on prior regimens. Patients may have received prior anti-PD-1/anti-PD-L1 in the neoadjuvant or adjuvant setting.
  • Participants must be HLA-A*02:01 in order for infused transgenic T cells to recognize antigen-major MHC complexes. HLA typing for HLA-A2 should be determined through molecular approaches at a clinical laboratory licensed for HLA testing.
  • Life expectancy must be anticipated to be > 3 months at trial entry.
  • Fewer than 0.5% of Merkel cell carcinomas occur in individuals aged 30 years or younger, thus the protocol includes only adult patients.
  • Capable of understanding and providing a written informed consent.
  • If fertile, willingness to comply with reproductive requirements.
  • Karnofsky performance status of >= 60%.
  • Should there be no tumor tissue that is accessible for biopsy, patients will still be considered for participation, at discretion of the investigator. Similarly, should an investigator determine that a biopsy cannot be performed safely for clinical reasons biopsies may be cancelled or retimed.
  • At least 3 weeks must have passed since any: immunotherapy (for example, T-cell infusions, immunomodulatory agents, interleukins, MCC vaccines, intravenous immunoglobulin, expanded polyclonal tumor infiltrating lymphocyte [TIL] or lymphokine-activated killer cell [LAK] therapy), natural killer (NK) therapy, small molecule or chemotherapy cancer treatment, other investigational agents or other systemic agents that target MCC. There is no washout period for radiation, so long as radiated lesion is not the lesion targeted for irradiation or RECIST measurements on the protocol.
  • Serum creatinine < 2.5 or estimated glomerular filtration rate (eGFR) > 30.
  • Total bilirubin (tBili) < 3.0. Patients with suspected Gilbert syndrome may be included if Tbili > 3 but no other evidence of hepatic dysfunction.
  • Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) < 5 x upper limit of normal (ULN).
  • =< grade 1 dyspnea.
  • Oxygen saturation (SaO2) >= 92% on ambient air.
  • If pulmonary function tests (PFTs) are performed based on the clinical judgment of the treating physician, patients with forced expiratory volume in one second (FEV1) >= 50% of predicted and diffusion capacity of the lung for carbon monoxide (DLCO) (corrected) of >= 40% of predicted will be eligible.
  • Patients 60 years of age or older are required to have left ventricular ejection fraction (LVEF) evaluation performed within 1 year prior to study treatment. LVEF may be established with echocardiogram or multigated acquisition (MUGA) scan, and must be >= 35%. Cardiac evaluation for other patients is at the discretion of the treating physician.
  • Absolute neutrophil count (ANC) > 1000 cells/mm^3.
  • Absolute lymphocyte count (ALC) > 200 cells/mm^3.
  • Hematocrit (HCT) > 30%.
  • Platelet count > 50K.

Exclusion Criteria

  • Pregnancy or lactation: Participants of childbearing potential must have a negative serum pregnancy test within the 2 weeks preceding FH-MCVA2TCR infusion. Childbearing potential is defined as women who have not been surgically sterilized and who are not post-menopausal (free of menses for at least 1 year).
  • Active autoimmune disease requiring immunosuppressive therapy is excluded unless discussed with the principal investigator (PI).
  • Kidney transplant will be considered on a case by case basis requiring discussion with PI. If kidney transplant, patient must have dialysis access, dialysis plan, supportive nephrologist, willingness to stop transplant immunosuppression, and express understanding that rejection is likely. Dialysis or costs related to transplant kidney will not be supported by the study. Participants having had any other solid organ transplants will be excluded, as will those with a history of allogeneic stem cell transplant.
  • Corticosteroid therapy at a dose equivalent of > 10 mg prednisone per day.
  • Concurrent use of other investigational agents or MCC directed therapies.
  • Chronic lymphocytic leukemia (CLL) or other active hematologic malignancy.
  • Active uncontrolled infection. Human immunodeficiency virus (HIV) positive participants on highly active antiretroviral therapy (HAART) with a CD4 count > 500 cells/mm^3 are considered controlled, as are individuals with a history of hepatitis C who have successfully completed antiviral therapy with an undetectable viral load, and those with hepatitis B who have hepatitis well controlled on medication.
  • Uncontrolled concurrent illness. Participants may not have uncontrolled or concurrent illness including, but not limited to, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.
  • Untreated brain metastases. Participants with small asymptomatic brain metastases (< 1 cm) or those with brain metastases previously treated with surgery or radiotherapy will be considered for inclusion at discretion of principal investigator, so long as other eligibility criteria are met.
  • Grade 3 or higher immune related adverse event (iRAE) to any prior PD-1 axis blocking agent.
  • Participants receiving treatment for prior immune-related adverse event (iRAE) are excluded, with exception of hormone supplementation or corticosteroid therapy at equivalent of up to 10 mg prednisone per day, unless otherwise approved by PI.
  • Study participants must not have significant active underlying neurologic disease, unless approved by PI. Mild neuropathy related to diabetes or prior chemotherapy is acceptable.
  • Other medical, social, or psychiatric factor that interferes with medical appropriateness and/or ability to comply with study, as determined by PI.


Fred Hutch / University of Washington Cancer Consortium
Status: ACTIVE
Contact: Joshua Veatch
Phone: 206-667-5108


I. To evaluate the safety of adoptive T cell therapy using FH-MCVA2TCR (defined as an observed treatment-related grade 3 or higher toxicity rate consistent with a true rate =< 40%).

II. To demonstrate clinical activity of FH-MCVA2TCR (defined as an observed response rate that statistically exceeds 5%).


I. Persistence of infused transgenic T cells in peripheral blood.

II. Migration of infused transgenic T cells into tumor tissue.

III. Determine progression free and overall survival of treated individuals.

IV. Determination of preferred dose of FH-MCVA2TCR.

V. Determine objective response rates by immune related Response Evaluation Criteria in Solid Tumors (RECIST) criteria.


I. Phenotype of infused T cells that persist and localize to tumor.

II. Functional capacity of infused transgenic T cells.

III. Determination of the presence or absence of epitope spreading (broadening of immune responses) to other Merkel cell polyomavirus (MCPyV) and/or neoantigen epitopes in the peripheral blood and/or tumor environment.

IV. Evaluation of changes in the tumor tissue and microenvironment that may correlate with success and/or failure of the autologous CD8+ and CD4+ transgenic T cells expressing high affinity MCPyV-specific T-cell receptors (TCRs) combined with avelumab and class I major histocompatibility complex (MHC) -upregulation (ATTAC) regimen.

OUTLINE: This is a dose escalation study of FH-MCVA2TCR autologous T-cells.

Patients receive FH-MCVA2TCR T-cells intravenously (IV) over 60-120 minutes. Patients also receive standard of care avelumab IV over 1 hour every 2 weeks for 1 year or pembrolizumab IV over 30 minutes every 3 weeks for 1 year and a single fraction of radiotherapy to one tumor lesion 3-5 days prior to T-cell infusion(s). Patients with partial response or stable disease may then receive an additional course of FH-MCVA2TCR T-cells.

After completion of study treatment, patients are followed up periodically for up to 15 years.

Trial Phase Phase I/II

Trial Type Treatment

Lead Organization
Fred Hutch / University of Washington Cancer Consortium

Principal Investigator
Joshua Veatch

  • Primary ID RG1003611
  • Secondary IDs NCI-2018-02483, ATTAC-MCC, 9845
  • ID NCT03747484