This phase II trial tests whether pegylated SN-38 conjugate PLX038 (PLX038) works to shrink tumors in patients with ovarian, primary peritoneal, and fallopian tube cancers that has spread from where it first started (primary site) to other places in the body (metastatic). PLX038 may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth.
PRIMARY OBJECTIVE: I. To estimate the overall tumor response rate (overall response rate \[ORR\], that is, complete response \[CR\] + partial response \[PR\], according to Response Evaluation Criteria in Solid Tumors version 1.1 \[RECIST v1.1\] of PLX038 in the setting of metastatic platinum resistant high grade serous ovarian cancer. SECONDARY OBJECTIVES: I. To estimate the progression-free survival and overall survival of treatment with PLX038. II. To describe and assess tolerability of PLX038. III. Measure PLX038 induced tumor TOP1-deoxyribonucleic acid (DNA) covalent complexes (TOP1cc) in pretreatment and Cycle 1 Day 8 biopsies to confirm persistent stabilization of TOP1cc and evaluate association with tumor response rate. CORRELATIVE RESEARCH: I. Measure TOP1cc in circulating tumor cells and evaluate association with TOP1cc in tumor tissue and tumor response rate. II. Assess homologous repair status and association with tumor response. III. Assess expression of SN-38 transports by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and association with tumor response. IV. Assess pharmacokinetics of SN-38 and SN-38G as well as their association with gastrointestinal (GI) toxicity. V. Assess the gut microbiota and evaluate association with GI toxicity profile. OUTLINE: Patients receive PLX038 intravenously (IV) over 1 hour on day 1 of each cycle. Cycles repeat every 21 days in the absence of disease progression or unacceptable toxicity. Patients also undergo computed tomography (CT), biopsy, as well as blood and stool sample collection during screening and on the trial. After completion of study treatment, patients are followed up at 30 days and every 6 months for up to 5 years.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
43
Undergo biopsy
Given IV
Undergo CT
Undergo blood and stool sample collection
Mayo Clinic
Rochester, Minnesota, United States
RECRUITINGProportion of confirmed tumor responses
A confirmed tumor response is defined to be either a complete response or partial response noted as the objective status on 2 consecutive evaluations at least 4 weeks apart. Confirmed tumor response will be evaluated using the first 6 cycles of treatment. All patients meeting the eligibility criteria who have signed a consent form, have begun treatment, and who have had at least one post-baseline tumor assessment will be evaluable for response. Patients not having met the criteria of having one post-baseline tumor assessment will be considered evaluable if they have discontinued the study due to disease progression.
Time frame: Up to first 6 cycles of treatment (1 cycle = 21 days)
Progression-free survival (PFS)
PFS will be estimated using the Kaplan-Meier method.
Time frame: From study entry to the first of either disease progression or death from any cause, assessed up to 5 years
Overall survival (OS)
OS will be estimated using the Kaplan-Meier method.
Time frame: From study entry to death from any cause, assessed up to 5 years
Incidence of adverse event rates
The maximum grade for each type of adverse event will be summarized using Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. The frequency and percentage of Grade 3+ adverse events will be reported.
Time frame: Up to 30 days
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