This is a non-therapeutic study assessing peripheral T cell determinants of response and resistance to immunotherapy in patients with advanced melanoma.The hypothesis is that systemic T cells traffic into the tumor microenvironment (TME) can predict response and resistance to immunotherapy. These systemic tumor directed T cells can be defined by tumor/blood small conditional RNA (scRNA) using T cell receptor (TCR) as a barcode and can help predict response to Programmed death-1 (PD-1) therapy.
Primary Objective: To understand how the systemic immune profile (T cell activation and expansion in TME) changes in response to pembrolizumab therapy in patients with advanced melanoma on pembrolizumab monotherapy. Exploratory Objectives : I. To correlate the peripheral T cell profiles with the objective response rate (ORR) at 24 weeks in patients with advanced melanoma on pembrolizumab monotherapy. II. To correlate the peripheral T cell profiles with progression free survival (PFS) in patients with advanced melanoma on pembrolizumab monotherapy. III. To correlate the peripheral T cell profiles with overall survival (OS) in patients with advanced melanoma on pembrolizumab monotherapy. IV. To correlate the peripheral T cell profiles with toxicity profile. V. Transcriptional and phenotypic features of tumor directed T cells in blood using a combination of phenotypic markers derived from COMET and cite-seq. Outline: Participants will have blood drawn and tumor biopsied. Participants will be followed for 6 months from time of treatment initiation. After 6 months, participants do not need to be followed but standard of care scans and survival status can be assessed for up to 5 years.
Study Type
OBSERVATIONAL
Enrollment
25
Tumor tissue collection
Intravenously Blood draw
University of California, San Francisco
San Francisco, California, United States
Number of Genes Predictive of Response at Baseline
The investigators will identify the genes predictive of response to anti-programmed death-1(PD-1) therapy by testing for significant associations across expression rates of each gene and response/resistance, within a hurdle-Gaussian mixed-effect framework that accounts for variance across patients and technical noise present in single-cell data. The overall number of genes predictive of response at baseline will be reported.
Time frame: At Baseline, 1 day
Number of Genes Predictive of Response at 24 Weeks
The investigators will identify the genes predictive of response to anti-PD-1 therapy by testing for significant associations across expression rates of each gene and response/resistance, within a hurdle-Gaussian mixed-effect framework that accounts for variance across patients and technical noise present in single-cell data. The overall number of genes predictive of response at week 24 will be reported.
Time frame: 24 weeks
Number of T-cell Sub-populations
The investigators will identify T cell sub-populations in the tumor-directed component in blood whose relative frequency is indicative of response to anti-PD-1 therapy, using a negative binomial regression model. The overall number of t-cell sub-populations will be reported.
Time frame: Up to 24 weeks
Proportion of Participants With a Change in Clonal Expansion of T Cells Associated With Response to Anti-PD-1 Therapy
The investigators will build a novel computational framework to identify T-cell clonal behavior associated with response to anti-PD-1 therapy using profiling of T-Cell Receptor (TCR) sequences at single-cell resolution to compare clonal expansion in each of the sub-population's association with response to anti-PD-1 therapy. The proportion of participants with a change in clonal expansion of T-cells associated with a response to anti-PD-1 therapy will be reported.
Time frame: Up to 24 weeks
Proportion of Participants With a Change in Distribution of T Cells Associated With Response to Anti-PD-1 Therapy
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The investigators will build a novel computational framework to identify T-cell clonal behavior associated with response to anti-PD-1 therapy using profiling of TCR sequences at single-cell resolution to compare distribution of T cells in each of the sub-populations for their association with response to anti-PD-1 therapy. The proportion of participants with a change in distribution of T cells associated with response to anti-PD-1 therapy will be reported.
Time frame: Up to 24 weeks
Number of Transcriptional Migration Events
The investigators will search for "transcriptional migration" events, in which T cell clones change their transcriptional profile following treatment and will assess the predictive power of such events to the success of anti-PD-1 therapy. The overall number of transcriptional migration events will be reported.
Time frame: Up to 24 weeks