Tavokinogene Telseplasmid with Electroporation, Pembrolizumab, and Epacadostat in Treating Patients with Unresectable Squamous Cell Carcinoma of the Head and Neck

Status: Active


This phase II trial studies how well tavokinogene telseplasmid with electroporation, pembrolizumab, and epacadostat work in treating patients with squamous cell carcinoma of the head and neck that cannot be removed by surgery. Tavokinogene telseplasmid with electroporation is a gene therapy that may delay of tumor growth and which may have less toxicity than other methods of gene delivery. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body’s immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Epacadostat may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Giving tavokinogene telseplasmid with electroporation, pembrolizumab, and epacadostat may work better in treating squamous cell carcinoma of the head and neck.

Eligibility Criteria

Inclusion Criteria

  • Eastern Cooperative Oncology Group (ECOG) performance status 0-2
  • Life expectancy of at least 4 months
  • Patients must have histological or cytological diagnosis of carcinoma of the head and neck that is not amenable to surgical resection or locoregional radiation therapy with curative intent
  • At least one tumor accessible lesion (AL) for intratumoral injection. An AL is defined as meeting the following criteria; (1) at least 0.3 cm x 0.3 cm in longest perpendicular diameters (2) in a suitable location for application of electroporation. Tumors invading the carotid artery or at other sites that the investigator believes to be at high risk of life-threatening hemorrhage should not be injected and these lesions may not be used to meet the inclusion criterion for injectable lesions
  • Measurable disease as defined by Response Evaluation Criteria in Solid Tumors (RECIST) version (v)1.1; at least one lesion where the longest perpendicular diameter is at least 1.0 cm by clinical measurement; or at least 1.0 cm by radiographic imaging for non-nodal lesions; at least 1.5 cm in short axis by radiographic imaging for malignant lymph nodes; If the biopsied lesions were previously irradiated, they must demonstrate either radiographic or pathological evidence of recurrent or residual disease. It is not necessary that this lesion is also an AL.
  • If patient has known brain metastases, they must have stable neurologic status following local therapy (surgery or radiation) for at least 4 weeks without the use of steroids or on stable or decreasing dose of =< 10 mg daily prednisone (or equivalent), and must be without neurologic dysfunction that would confound the evaluation of neurologic and other adverse events (AEs) (patients with a history of carcinomatous meningitis are not eligible)
  • Patients may have had prior chemotherapy or immunotherapy or radiation therapy. Any drug related adverse events identified during prior therapy must be well controlled (typically resolution to =< grade 1, OR resolved upon investigator review prior to initiation of this therapy
  • No systemic antineoplastic therapy may be received by the patient between the time of the biopsy and the first administration of study treatment
  • Patient must agree to any protocol mandated biopsies of tumor (deemed accessible and safe for biopsy by the investigator’s assessment) and they must allow acquired tissue to be used for biomarker analysis
  • For women of childbearing potential, negative serum or urine pregnancy test within 14 days to the first epacadostat, pembrolizumab, or tavo-EP administration, and use of birth control from 30 days prior to the first epacadostat, pembrolizumab, or tavo-EP administration and 120 days following last day of epacadostat, pembrolizumab, or tavo-EP administration
  • Male patients must be surgically sterile, or must agree to use contraception during the study and at least 120 days following the last day of epacadostat, pembrolizumab, or tavo-EP administration

Exclusion Criteria

  • Active autoimmune disease that has required systemic treatment in past 2 years. Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency) is not considered a form of systemic treatment
  • Congestive heart failure (New York Heart Association class III to IV)
  • History or presence of an abnormal electrocardiogram (ECG) that, in the investigator's opinion, is clinically meaningful. Screening corrected QT (QTc) interval > 480 milliseconds is excluded. In the event that a single QTc is > 480 milliseconds, the subject may enroll if the average QTc for the 3 ECGs is < 480 milliseconds. For subjects with an intraventricular conduction delay (QRS interval > 120 milliseconds), the corrected JT (JTc) interval may be used in place of the QTc with sponsor approval. The JTc must be < 340 milliseconds if JTc is used in place of the QTc. Subjects with left bundle branch block are excluded
  • Uncontrolled or clinically significant conduction abnormalities (e.g., ventricular tachycardia on anti-arrhythmics are excluded), 1st degree atrioventricular (AV) block or asymptomatic left anterior fascicular block (LAFB)/right bundle branch block (RBBB) are eligible
  • Uncontrolled, symptomatic ischemia within 6 months of first dose of study treatment or known myocardial infarction in the previous six months
  • Patients with electronic pacemakers or defibrillators
  • Evidence of interstitial lung disease or active, noninfectious pneumonitis including symptomatic and/or pneumonitis requiring treatment
  • Any other current or previous malignancy within the past 2 years that, in the opinion of the principal investigator will interfere with study-specific endpoints
  • Evidence of significant active infection (e.g., pneumonia, cellulitis, wound abscess, etc.) requiring systemic therapy at time of study enrollment
  • Hepatitis B – Most nasopharyngeal cancer (NPC) patients have been infected with hepatitis B (Cancer Epidemol Biomarkers Prev. 2015. 24:1766-73, N = 711) and, therefore, the inclusion of healthy patients with a history of hepatitis B is a central part of this study. In addition, PD-1 antibodies have been proven to be safe in patients with active hepatitis and hepatocellular carcinoma (e.g. KEYNOTE 224). However, patients with hepatitis B virus (HBV) surface antigen positive (HBSAg) must have aspartate aminotransferase (AST) and total bilirubin < 1.5 x upper limit of normal (ULN) AND
  • Negative HBV ribonucleic acid (RNA) polymerase chain reaction (PCR) OR
  • On antivirals for HBV AND at least 8 weeks of prior anti-PD1 antibody therapy AND no history of AST or total bilirubin levels > 1.5 x ULN due to PD-1 antibody therapy
  • Hepatitis C (hepatitis C virus [HCV] RNA [qualitative] is detected)
  • Presence of a gastrointestinal condition that may affect drug absorption. Administration of epacadostat through a feeding tube is permitted
  • Patients receiving systemic steroid therapy for a chronic inflammatory condition. Topical steroids, nasal and inhaled steroids are permitted. Prednisone or equivalent =< 10 mg/day is permitted as hormone replacement; higher dosage prednisone should be stopped at least 14 days prior to cycle 1 day 1 (C1D1)
  • Receipt of live attenuated vaccine within 30 days before the first dose of study treatment. Examples of live vaccines include, but are not limited to, the following: measles, mumps, rubella, chicken pox, yellow fever, rabies, Bacillus Calmette-Guerin (BCG), and typhoid vaccine. Seasonal influenza vaccines for injection are generally killed virus vaccines and are allowed; however, intranasal influenza vaccines (e.g., FluMist) are live attenuated vaccines and are not allowed
  • Subjects receiving monoamine oxidase inhibitors (MAOIs) or drug which has significant MAOI activity (meperidine, linezolid, methylene blue) within the 21 days before screening
  • Any history of serotonin syndrome (SS) after receiving serotonergic drugs
  • Use of any UGT1A9 inhibitor from screening through follow-up period, including the following: diclofenac, imipramine, ketoconazole, mefenamic acid, and probenecid
  • Known allergy or reaction to any component of epacadostat, pembrolizumab, or tavo-EP formulation
  • Absolute neutrophil count (ANC) < 1.0 x 10^9/L
  • Platelets < 75 x 10^9/L
  • Hemoglobin < 9 g/dL or < 5.6 mmol/L (transfusion is acceptable to meet this criterion)
  • Serum creatinine >= 1.5 x institutional upper limit of normal (ULN) OR measured or calculated creatinine clearance (glomerular filtration rate can also be used in place of creatinine or creatinine clearance [CrCl]) < 50 mL/min for subjects with creatinine levels > 1.5 x institutional ULN
  • AST or alanine aminotransferase (ALT) > 2.5 x institutional ULN
  • Alkaline phosphatase > 2.5 x ULN. Note: Subjects with 1) bone metastases and gamma-glutamyl transpeptidase (GGT) < 2.5 x ULN may enroll if the alkaline phosphatase is < 5 x ULN
  • Total bilirubin above 1.5 x the institutional ULN AND conjugated bilirubin >= 2.0 x ULN
  • International normalized ratio (INR) or prothrombin time (PT) > 1.5 x ULN
  • Activated partial thromboplastin time (aPTT) > 1.5 x ULN

Locations & Contacts


San Francisco
UCSF Medical Center-Mount Zion
Status: Active
Contact: Chase M Heaton
Email: chase.heaton@ucsf.edu

Trial Objectives and Outline


I. Determine whether the combination of tavokinogene telseplasmid (tavo)-electroporation (EP), pembrolizumab, and epacadostat increases the best overall response rate (BORR) in squamous cell carcinoma of the head and neck (SCCHN) compared with historical data for pembrolizumab monotherapy.


I. Assess the safety of tavo-EP and pembrolizumab in combination with epacadostat (Common Terminology Criteria for Adverse Events [CTCAE] version 4).

II. Determine the durability of clinical benefits in patients treated with tavo-EP, pembrolizumab, and epacadostat as assessed by time to progression, median progression-free survival (PFS), median overall survival (OS).


I. Determine whether the combination of tavo-EP, pembrolizumab, and epacadostat increases the objective response rate in SCCHN compared with emerging data for pembrolizumab in combination with epacadostat.

II. Determine the effects of combination therapy on treated and untreated lesions by examining paired biopsy specimens for changes in inflammatory gene expression, relative proportion of effector versus regulatory T cells, evaluation of inflammatory cytokines, T-cell activation, clonality, and other hallmarks of immune activation.

III. Explore systemic markers of immune activation by examining circulating T-cell populations for changes in the frequency and effector function of short-lived effector cells and memory T cells.

IV. Explore changes in functional immune responses using enzyme-linked immunosorbent spot (Elispot) and other assays.

V. To explore biomarkers that inform scientific understanding of this therapeutic treatment through analysis of specimens retained for Future Biomedical Research.


Patients receive tavokinogene telseplasmid intratumorally (IT) and undergo electroporation on days 1, 5 and 8. Patients also receive pembrolizumab intravenously (IV) over 30 minutes on days 1 and 22, and epacadostat orally (PO) twice daily (BID). Treatment repeats every 42 days (6 weeks) for up to 9 cycles or 12 months in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed up at 30 days, then every 3 months for up to 36 months or 30 days after disease progression.

Trial Phase & Type

Trial Phase

Phase II

Trial Type


Lead Organization

Lead Organization
UCSF Medical Center-Mount Zion

Principal Investigator
Chase M Heaton

Trial IDs

Primary ID 172021
Secondary IDs NCI-2018-02901, 17-24044
Clinicaltrials.gov ID NCT03823131