Utility of serum CA-125 monitoring in patients with ovarian cancer undergoing immune checkpoint inhibitor therapy.

OBJECTIVE: This study aimed to evaluate the utility of serum cancer antigen-125 (CA-125) levels to monitor patients with epithelial ovarian cancer (EOC) undergoing immune checkpoint inhibitor (ICI) therapy. METHOD: This was a single-center retrospective review of all patients with EOC who were treated with ICI therapy from January 2013 to May 2017. This study compared the percentage change in baseline CA-125 in patients who had clinical benefit, defined as complete response, partial response, or stable disease by RECIST 1.1, with duration ≥24 weeks, versus those who did not. The groups were compared by Wilcoxon rank-sum test. RESULTS: Fifty-nine (66%) of 89 patients who underwent ICI therapy had CA-125 data at baseline and during treatment. Of those who derived clinical benefit, 11/15 (73%) experienced an increase in CA-125 from baseline to end of treatment. Of those who did not derive clinical benefit, 36/44 (82%) experienced a CA-125 increase (p = 0.48). The average % increase from baseline to within 12 weeks of treatment initiation for patients with and without clinical benefit was 34% and 195%, respectively (p = 0.008). CONCLUSION: Our analysis demonstrates a statistically significant difference in the magnitude of increase in CA-125 levels within the first 12 weeks of treatment between patients who achieved clinical benefit and those who did not. However, both groups of patients were equally likely to experience an increase in CA-125 within 12 weeks. These findings suggest that physicians should apply caution when using early CA-125 data to guide treatment decisions for patients with EOC undergoing ICI therapy.

Early disease progression and treatment discontinuation in patients with advanced ovarian cancer receiving immune checkpoint blockade.

OBJECTIVE: Delayed responses observed with immune checkpoint blockade (ICB) present a challenge for patients with peritoneal malignancies, who risk early symptomatic disease progression requiring treatment discontinuation. While efforts are ongoing to define the biomarkers of response, it is equally important to identify patients at risk for early discontinuation. We sought to investigate the timing of disease progression in epithelial ovarian cancer (EOC) patients treated with ICB and to identify pre-treatment clinical parameters associated with early discontinuation. METHODS: Retrospective analysis was performed on EOC patients treated with ICB at MSKCC from January 2013 to May 2017. Cutoffs for early and very early discontinuation due to disease progression were defined at 12 and 8 weeks, respectively. Univariate and multivariate logistic regression models were built based on pre-treatment clinical variables. RESULTS: Of 108 identified patients, 89 were included in the analysis. Forty-six (51.7%) patients discontinued therapy early, 30 of which (33.7%) discontinued therapy very early. Eight patients (9.0%) died within 12 weeks of ICB initiation from disease progression. In multivariate analyses, bulky peritoneal disease (p = 0.009, OR: 4.94) and liver parenchymal metastases (p = 0.001, OR: 8.08) were associated with early discontinuation. Liver parenchymal metastases (p = 0.001, OR 6.64), and high neutrophil-to-lymphocyte ratio (p = 0.021, OR: 3.54), were associated with very early discontinuation. CONCLUSIONS: Over 50% of EOC patients suffer disease progression requiring early discontinuation of ICB. Pre-treatment prognostic clinical characteristics may identify patients at highest risk for early discontinuation due to disease progression and warrant caution in using these agents in late line patients with advanced disease.

Safety, immunogenicity, and clinical efficacy of durvalumab in combination with folate receptor alpha vaccine TPIV200 in patients with advanced ovarian cancer: a phase II trial.

BACKGROUND: Immune checkpoint inhibitors (ICIs) to date have demonstrated limited activity in advanced ovarian cancer (OC). Folate receptor alpha (FRα) is overexpressed in the majority of OCs and presents an attractive target for a combination immunotherapy to potentially overcome resistance to ICI in OCs. The current study sought to examine clinical and immunologic responses to TPIV200, a multiepitope FRα vaccine administered with programmed death ligand 1 (PD-L1) inhibitor durvalumab in patients with advanced platinum-resistant OC. METHODS: Following Simon two-stage phase II trial design, 27 patients were enrolled. Treatment was administered in 28-day cycles (intradermal TPIV200 and granulocyte-macrophage colony-stimulating factor (GM-CSF) for 6 cycles and intravenous durvalumab for 12 cycles). Primary endpoints included overall response rate and progression-free survival at 24 weeks. Translational parameters focused on tumor microenvironment, PD-L1 and FRα expression, and peripheral vaccine-specific immune responses. RESULTS: Treatment was well tolerated, with related grade 3 toxicity rate of 18.5%. Increased T cell responses to the majority of peptides were observed in all patients at 6 weeks (p<0.0001). There was one unconfirmed partial response (3.7%) and nine patients had stable disease (33.3%). Clinical benefit was not associated with baseline FRα or PD-L1 expression. One patient with prolonged clinical benefit demonstrated loss of FRα expression and upregulation of PD-L1 in a progressing lesion. Despite the low overall response rate, the median overall survival was 21 months (13.5-∞), with evidence of benefit from postimmunotherapy regimens. CONCLUSIONS: Combination of TPIV200 and durvalumab was safe and elicited robust FRα-specific T cell responses in all patients. Unexpectedly durable survival in this heavily pretreated population highlights the need to investigate the impact of FRα vaccination on the OC biology post-treatment.