This was a Phase 2, open-label study of the NY-ESO-1 ISCOMATRIX® (ISCOM) vaccine administered as an intramuscular injection given every 4 weeks to subjects with measurable advanced malignant melanoma. Study objectives included determination of the anticancer activity, cellular and humoral immunogenicity, and safety and tolerability of the NY-ESO-1 ISCOM vaccine administered alone or preceded by a single administration of low-dose cyclophosphamide.
In Cohort 1, 6 subjects were initially vaccinated with the NY-ESO-1 ISCOM vaccine at a dose of 100 µg of the NY-ESO-1 protein + 120 µg of the ISCOM adjuvant. These 6 subjects were monitored for dose-limiting toxicity (DLT) for 7 days after the first vaccination. Upon observation of tolerability (ie, \< 2/6 subjects with DLT), enrollment proceeded to a total accrual of approximately 25 subjects. Subjects received 3 vaccinations administered every 4 weeks (ie, weeks 1, 5, and 9) followed by immunological and clinical response evaluations, with clinical responses categorized according to the Response Evaluation Criteria in Solid Tumors (RECIST). In the absence of disease progression, subjects may have received 3 additional vaccinations administered every 4 weeks, followed by additional vaccinations administered every 12 weeks thereafter until development of disease progression or other criteria for discontinuation. In Cohort 2, subjects received the NY-ESO-1 ISCOM vaccine on the same schedule as described for Cohort 1, but Cohort 2 subjects also received a single intravenous infusion of low-dose cyclophosphamide 1 day prior to each NY-ESO-1 ISCOM vaccination. If responses were observed in 2 of 16 subjects initially treated in Cohort 2, then 9 additional subjects were to be accrued to Cohort 2, for a total potential accrual of 25 subjects.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
46
NY-ESO-1 ISCOM vaccine (100 μg of the NY-ESO-1 protein formulated with 120 μg of ISCOM adjuvant) administered as an intramuscular injection every 4 weeks for 3 doses in every cycle.
Cyclophosphamide (300 mg/m\^2) administered as an intravenous injection 1 day prior to each vaccination with NY-ESO-1 ISCOM (100 μg of the NY-ESO-1 protein formulated with 120 μg of ISCOM adjuvant), which was administered as an intramuscular injection every 4 weeks for 3 doses in every cycle.
Peter MacCallum Cancer Institute
East Melbourne, Victoria, Australia
Austin Health (Ludwig Institute Oncology Unit)
Heidelberg, Victoria, Australia
Number of Subjects With Best Overall Tumor Response
Tumor responses were evaluated using computed tomography and categorized according to RECIST (version 1.0) at baseline, at week 11, between weeks 23 and 25, and every 12 weeks thereafter. Per RECIST, target lesions are categorized as follows: Complete Response (CR): Disappearance of all target lesions \[no evidence of disease\]; Partial Response (PR): ≥ 30% decrease in the sum of the longest diameter of target lesions; Progressive Disease (PD): ≥ 20% increase in the sum of the longest diameter of target lesions; Stable Disease (SD): small changes that do not meet above criteria.
Time frame: Up to 22 months
Cellular Immunogenicity of the NY-ESO-1 ISCOM Vaccine
Blood samples were drawn to measure cellular response at pretreatment and weeks 3, 7, 11, between weeks 23 and 25, week 33, and every 12 weeks thereafter. Cellular immunity included an assay for gamma interferon-producing T cells and enumeration of NY-ESO-1b-specific T cells, detected by fluorescent labeled human leukocyte antigen (HLA)-A2 tetramers carrying the NY-ESO-1b peptide, expressed as percent positive staining of CD4+ and CD8+ T cells. Data are presented for CD4+ and CD8+ T-cell responses (not mutually exclusive) that were pre-existing at baseline (BL) or presented at any time post-BL.
Time frame: Up to 22 months
Post-Vaccination Delayed-type Hypersensitivity (DTH) Reactions
NY-ESO-1-specific DTH was measured by intradermal injection with the full-length NY-ESO-1 protein, NY-ESO-1b peptide, and NY-ESO-1 DP4 peptide at pretreatment, week 11, and between week 23 and 25. DTH reactions (eg, local skin irritation) were evaluated 2 days after DTH injections. Data presented are based on injections with the full-length peptide, as these data are considered to be representative of the comprehensive DTH results.
Time frame: Up to 22 months
Humoral Immunogenicity of the NY-ESO-1 ISCOM Vaccine
Blood samples were drawn to measure humoral immunologic response at pretreatment and weeks 3, 7, 11, 33, and every 12 weeks thereafter. Humoral immunity was assessed by measurement of antibodies to NY-ESO-1 by enzyme-linked immunosorbent assay (ELISA). Data are presented according to baseline (BL) NY-ESO-1 antibody positivity and the time to seroconversion, if applicable.
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Time frame: Up to 22 months
Number of Subjects With Treatment-emergent Adverse Events
Toxicity was graded in accordance with the National Cancer Institute Common Terminology Criteria for Adverse Events (version 3.0). Treatment-emergent adverse events (TEAEs) were reported based on clinical laboratory tests, physical examinations, and vital signs from pre-treatment through the study period. Dose-limiting toxicity was defined as any treatment-related grade 4 toxicity or any grade 3 toxicity, excluding grade 3 skin necrosis at the site of the delayed-type hypersensitivity reaction, fever, or asymptomatic hyperglycemia that improved to baseline within 3 weeks of onset.
Time frame: Up to 22 months