This phase II trial studies the effectiveness of ImmunoPulse IL-12® in treating patients with Merkel cell cancer. ImmunoPulse IL-12® is the combination of intratumoral interleukin-12 gene (also known as tavokinogene telseplasmid \[tavo\]) and in vivo electroporation-mediated plasmid deoxyribonucleic acid \[DNA\] vaccine therapy (tavo-EP) administered using the OncoSec Medical System (OMS). Placing the gene for interleukin-12 into Merkel cells may help the mount an effective anti-tumor immune response to kill tumor cells.
PRIMARY OBJECTIVES: I. To measure the effect of intratumoral injection of tavo followed by in vivo electroporation (EP) (electroporation-mediated plasmid DNA vaccine therapy) on the local expression of interleukin-12 (IL-12) in the tumor microenvironment in patients with Merkel cell carcinoma (MCC). SECONDARY OBJECTIVES: I. To assess the safety of tavo-EP in MCC. II. To assess the clinical efficacy of this treatment approach in MCC. III. To assess the immunologic changes resulting from this treatment approach. OUTLINE: Patients receive tavo intratumorally (IT) and undergo electrical discharge via OMS around the tumor site for electroporation-mediated plasmid DNA vaccine therapy on days 1, 5, and 8. Patients with unresectable disease may receive a second course of treatment in 12 weeks. Patients with localized disease proceed to definitive treatment as determined by the treating physician starting 2-4 weeks after the first injection. After completion of study treatment, patients are followed up at weeks 4-8 (for patients who received definitive treatment) or 12 (for patients with unresectable disease) and then annually for up to 5 years.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
15
Patients received intratumoral injection(s) of tavo.
Electroporation via OMS was performed immediately following intratumoral injection of tavo. A sterile applicator containing 6 stainless steel electrodes arranged in a circle were placed around the tumor. The applicator was connected to the OMS power supply and six pulses were administered to each tumor lesion at the approximate point of tavo injection.
Fred Hutchinson Cancer Research Center/University of Washington Cancer Consortium
Seattle, Washington, United States
Percentage of Participants Who Experienced At Least 2-Fold Increase in Expression of IL-12 Protein in the Tumor Tissue After Intratumoral (IT) pIL-12 Injections and In Vivo Electroporation
The MAGPIX assay was used to assess differential expression of hIL-12 in patient tumor tissue before and after treatment with intratumoral (IT) tavo injections and in vivo electroporation (EP). Expression of hIL-12 was used to identify patients who met the primary endpoint of a 2-fold or higher increase in expression of hIL-12 in tumors after treatment. Fold change was taken as a comparison of hIL-12 expression at Week 3:pre-treatment, Week 6:pre-treatment, Week 8:pre-treatment, or Week 13:pre-treatment over baseline (pre- treatment). The fold change was calculated as log2 (time point/baseline).
Time frame: Pre-treatment up to Week 13
Percentage of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs)
An AE was any untoward medical occurrence in a patient or clinical investigation participant administered a pharmaceutical product, medical treatment or procedure and which did not necessarily have to have had a causal relationship with this treatment. An adverse event could have, therefore, been any unfavorable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a medicinal product, medical treatment or procedure whether or not considered related to the medicinal product. An SAE was defined an any untoward medical occurrence that at any dosage resulted in one or more of the following: death, A life-threatening adverse event (real risk of dying), inpatient hospitalization or prolongation of existing hospitalization, persistent or significant disability/incapacity, congenital anomaly, required intervention to prevent permanent impairment of damage.
Time frame: From signing of informed consent to 8 weeks after the last dose of study treatment (up to 15 months)
Objective Response Rate (ORR) in Injected and Non-injected (Distant) Lesions
ORR is defined as the percentage of participants with evaluable lesions that achieved a complete response (CR) or partial response (PR) as assessed by the investigator using Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1. CR: Disappearance of all target lesions, non-target lesions, no new lesions, and normalization of tumor marker level. PR: At least a 30% decrease in the sum of diameters of target lesions, no progression in non-target lesion, and no new lesions. The same method was used to assess response rate for treated lesions and response rate for non-treated lesions. The best response rate for non-treated lesions was based on the number of patients who had at least one non-treated lesion.
Time frame: 3-4 weeks after the first dose in each cycle and then every 3 months until disease progression, death or withdrawal of consent (up to 15 months)
Time to Progression (TTP)
TTP is defined as the number of days between the treatment initiation date (Study Day 1) and the earliest date of documented disease progression as defined by RECIST 1.1 or death that is not associated with prior disease progression. Progression is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.1), as a 20% increase in the sum of the longest diameter of target lesions, or a measurable increase in a non-target lesion, or the appearance of new lesions.
Time frame: 3-4 weeks after the first dose in each cycle and then every 3 months until disease progression, death or withdrawal of consent (up to 15 months)
Overall Survival
Overall survival is defined as the time in days from the date of first study drug administration to the date of death.
Time frame: From the start of study treatment until death (up to 15 months)
Immunologic Effects of IT pIL-12 Injection and In Vivo EP Measured By: Percentage of Participants With a Positive Fold Change (Log2) in IL-12A Messenger Ribonucleic Acid (mRNA) for Patient Pre- and Post IT pIL 12 EP
Nanostring analysis was performed to determine the expression (mRNA) of IL-12. For each study patient, the fold change (log2 transformed) in IL-12A mRNA as measured by Nanostring was determined using the pre-treatment (screening) biopsy as a reference for the post treatment biopsy. A log2 fold change \>=1 is a positive result.
Time frame: Pre-treatment up to Week 13
Local Regression Rate
Local regression rate is defined as the percentage of participants with ≥30% regression (decrease in size) of at least one assessed local (injected) lesion.
Time frame: 3-4 weeks after the first dose in each cycle and then every 3 months until disease progression, death or withdrawal of consent (up to 15 months)
Distant Regression Rate
Distant regression rate is defined as the percentage of participants with ≥30% regression (decrease in size) of at least one assessed distant (non-injected) lesion.
Time frame: 3-4 weeks after the first dose in each cycle and then every 3 months until disease progression, death or withdrawal of consent (up to 15 months)
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