This was a phase 1/2, open-label, dose-escalation study of arginine deiminase linked via succinimidyl succinate to polyethylene glycol of 20,000 molecular weight (ADI-PEG 20) in subjects with advanced melanoma. ADI-PEG 20 was administered intramuscularly (IM) at escalating doses weekly for 9 weeks (cycle 1) or 8 weeks (subsequent cycles). The primary objectives were to the establish the safety, tolerability, and clinical efficacy of ADI-PEG 20. Secondary objectives included evaluation of the metabolic activity by \[18F\]-fluorodeoxyglucose positron emission tomography (FDG PET), pharmacodynamics, correlation of immunogenicity with clinical response, and correlation of argininosuccinate synthetase (ASS) tumor expression with clinical response.
A 3+3 design was implemented during phase 1, in which 3 to 6 subjects were enrolled sequentially into the following escalating dose cohorts: * Cohort 1 (40 IU/m\^2) * Cohort 2 (80 IU/m\^2) * Cohort 3 (160 IU/m\^2) Subjects were monitored for dose-limiting toxicity (DLT) during the first 2 weeks of cycle 1, with DLT defined as any grade 3 or higher toxicity. The maximum tolerated dose (MTD) was defined as the cohort in which \< 33% of subjects (ie, 0/3 or 1/6 subjects in a cohort) experienced DLT. In phase 2, the MTD cohort was expanded in up to 25 patients. Subjects who completed treatment in cycle 1 without DLT were eligible to initiate cycle 2 at week 10 provided that a computed tomography (CT) scan showed either enlargement of existing disease without accompanying symptoms OR stable disease or improvement with no unacceptable toxicity. The same radiologic criteria applied for initiation of subsequent cycles. Subjects could continue to receive study treatment until disease progression.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
31
Intramuscular injections were administered into the deltoid, gluteal, or quadricep muscles once weekly (± 2 days) for 9 weeks during cycle 1 and 8 weeks during subsequent cycles
NYU Cancer Institute
New York, New York, United States
Memorial Sloan-Kettering Cancer Center
New York, New York, United States
Assessment of Safety and Tolerability of ADI-PEG 20
Analysis of treatment-emergent adverse events (TEAEs) reported from clinical laboratory tests, physical examinations, and vital signs.
Time frame: Every 1 to 2 weeks for up to 12 months
Best Overall Clinical Tumor Response
Clinical tumor responses were evaluated using disease imaging (CT preferred) performed at baseline and at the end of every cycle. Responses were categorized according to RECIST. Per RECIST for target lesions and assessed by MRI: 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: Every 8 to 9 weeks for up to 12 months
Metabolic Tumor Response
Metabolic tumor responses were evaluated using fluorodeoxyglucose (FDG) positron emission tomography (PET) at baseline, on day 4, and at the end of every cycle.
Time frame: Every 8 to 9 weeks for up to 12 months
Summary of ADI-PEG 20 Plasma Concentrations Over Time
Blood samples were collected on day 1 (pre-injection), day 4, day 8, and every 7 days thereafter for ADI-PEG 20 plasma concentrations.
Time frame: Up to 12 months
Summary of Plasma Arginine Levels Over Time
Blood samples were collected at baseline, day 1 (pre-injection), day 4, day 8, and every 7 days thereafter for plasma arginine levels.
Time frame: Up to 9 months
Summary of Plasma Citrulline Levels Over Time
Blood samples were collected at baseline, day 1 (pre-injection), day 4, day 8, and every 7 days thereafter for plasma citrulline levels.
Time frame: Up to 9 months
Summary of ADI-PEG 20 Immunogenicity Over Time
Blood samples were collected at baseline, day 1 (pre-injection), day 4, day 8, and every 7 days thereafter for detection of anti-ADI antibodies.
Time frame: Up to 12 months
Correlation Between ASS Tumor Expression and Clinical Response
Expression of ASS was analyzed by immunohistochemistry in tumor samples (archived or biopsy) at baseline and compared with overall best clinical response per RECIST. ASS tumor expression is categorized as either negative or ≤ 5% positive tumor cells.
Time frame: Up to 12 months
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