Immune Activation in Patients with Locally Advanced Cervical Cancer Treated with Ipilimumab Following Definitive Chemoradiation (GOG-9929)

Abstract

Purpose: A phase I clinical trial (GOG-9929) examined the safety and efficacy of adjuvant immune-modulation therapy with the checkpoint inhibitor ipilimumab [anti-CTL antigen-4 (anti-CTLA-4)] following chemoradiation therapy (CRT) for newly diagnosed node-positive human papillomavirus (HPV)-related cervical cancer. To better understand the mechanism of action and to identify predictive biomarkers, immunologic and viral correlates were assessed before, during, and after treatment.

Patients and methods: Twenty-one patients who received CRT and ≥2 doses of ipilimumab and 5 patients who received CRT only were evaluable for translational endpoints. Circulating T-cell subsets were evaluated by multiparameter flow cytometry. Cytokines were evaluated by multiplex ELISA. HPV-specific T cells were evaluated in a subset of patients by IFNγ ELISpot.

Results: Expression of the activation markers ICOS and PD-1 significantly increased on T-cell subsets following CRT and were sustained or increased following ipilimumab treatment. Combined CRT/ipilimumab treatment resulted in a significant expansion of both central and effector memory T-cell populations. Genotype-specific E6/E7-specific T-cell responses increased post-CRT in 1 of 8 HPV16+ patients and in 2 of 3 HPV18+ patients. Elevation in levels of tumor-promoting circulating cytokines (TNFα, IL6, IL8) post-CRT was significantly associated with worse progression-free survival.

Conclusions: Our data indicate that CRT alone and combined with ipilimumab immunotherapy show immune-modulating activity in women with locally advanced cervical cancer and may be a promising therapeutic option for the enhancement of antitumor immune cell function after primary CRT for this population at high risk for recurrence and metastasis. Several key immune biomarkers were identified that were associated with clinical response.

Trial registration: ClinicalTrials.gov NCT01711515.

Conflict of interest statement

Disclosure of Potential Conflicts of Interest

DMD, DME, JGS, HQP, HAL, and WMK have no conflicts to disclose. JSM is a consultant for Varian Medical Systems and reports receiving honoraria and travel reimbursement from AstraZeneca. KM reports receiving honoraria from Chugai, textbook editorial support from Springer, and travel reimbursement from VBL Therapeutics. KMM is a consultant for Tessa Therapeutics and Clovis Oncology. SAG is a consultant for Seattle Genetics; reports receiving research grants from GlaxoSmithKline, Merck, Genentech-Roche, Takeda, Seattle Genetics, Advaxis, Bristol-Meyers Squibb, Abbvie and Tesaro; received travel reimbursement from Intuitive Surgical and Merck; participates in Speakers’ Bureau for Tesaro/GlaxoSmithKline. YGL is an employee of Genentech-Roche; has stock ownership in Genentech-Roche; is a consultant for Venn Biosciences Corporation. RJS is a consultant for Celsion, Incyte, Flatiron Health, Immunogen, and Clovis Oncology. MJB is a consultant for Genentech-Roche, Sanofi, Acceleron Pharma, Merrimack, Oxigene, Threshold Pharmaceuticals, Immunogen, Clovis Oncology, Tesaro, and AstraZeneca.

©2020 American Association for Cancer Research.

Figures

Figure 1.. Represented high-risk HPV types in patients enrolled in GOG9929.

Sampling of the cervix of each subject at baseline was performed to determine probable HPV genotype of the cervical cancer. Isolated genomic DNA was tested in the INNO-LiPA HPV Genotyping Extra assay. Shown is the number of cases detected for the listed high-risk HPV genotypes. Seven patient samples were positive for more than one HPV type. HPV16 and HPV18 were the most frequently detected HPV genotypes in this patient population.

Figure 2.. Circulating T cell subsets and expression of immune activation markers.

PBMC subsets and expression of T cell activation markers were assessed in all evaluable patients (PP and ITT) with a baseline (pre-CRT) sample, a post-CRT sample, and a post-ipilimumab sample (in PP patients) by multi-parameter flow cytometry. (A) Percentages of CD4 and CD8 T cells are shown. (B) Percentage of Tregs and ratio of CD8:Tregs is shown. (C) For activation marker expression, the percentage change from baseline is shown. Response is color coded for recurrence-free censored patients (black symbols) versus patients with disease recurrence during the follow-up period (red symbols). *p

Figure 3.. Changes in circulating T cell memory subsets post CRT and ipilimumab treatment.

(A) Percentage change from baseline in CD4+ T cell memory subsets. (B) Percentage change from baseline in CD8+ T cell memory subsets. Percentages were calculated from CD3+CD4+ or CD3+CD8+ gated lymphocytes. Response is color coded for recurrence-free censored patients (black symbols) versus patients with disease recurrence (red symbols). *p

Figure 4.. Association of changes in immune biomarkers with progression-free survival.

Increased changes (baseline to post-CRT values) in immune parameters were related to PFS using adjusted Cox proportional hazards models, with each variable fit in individual model adjusted for baseline value. Figure shows hazard ratios with 95% confidence intervals (lower limit, upper limit) and associated p-values for statistically significant associations found for immune activation markers and plasma cytokines. Expansion of the CD4+ICOS+ and CD4+ICOS+PD-1+ subsets post-CRT are associated with lower risk of progression while increases in inflammatory cytokines TNFα, IL-6, and IL-8 post-CRT are associated with higher risk of tumor progression. Nineteen PP and five ITT patients were included in immune phenotyping analysis. Twenty-one PP and five ITT patients were included in cytokine analysis.

Figure 5.. HPV16 or HPV18-specific T cell responses detected by IFNγ ELISpot assay.

HPV-specific T cell responses were detected at baseline, post-CRT and post-ipilimumab from a subset of evaluable patients who tested positive for either HPV16 or HPV18 at baseline. Shown is the number of IFNγ-secreting protein-specific T cells (in spots per million PBMC) responding to either E6 or E7 peptides from each HPV genotype. Sample time points labeled “nd” were not tested due to insufficient cell numbers or quality recovered post-PBMC thaw. The dotted horizontal line indicates the threshold for a positive response (> 50 IFNγ-secreting cells per million PBMC) based on assay sensitivity. Samples labeled with an asterisk indicate significant increases in HPV-specific T cells ≥ 2-fold over baseline.