Wessling, Jaclynn

Abstract Background We sought to determine the safety and efficacy of trifluridine/tipiracil in combination with irinotecan in a phase II trial setting for refractory, advanced unresectable biliary tract carcinoma (BTC). Methods A total of 28 patients (27 were evaluable) with advanced BTCs who progressed on at least one prior systemic therapy were enrolled and were treated with trifluridine/tipiracil 25 mg/m2 (days 1-5 of 14-day cycle) and irinotecan 180 mg/m2 (day 1 of the 14-day cycle). The primary endpoint for the study was 16-week progression-free survival (PFS16) rate. Overall survival (OS), progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and safety were pre-specified secondary endpoints. Results Of 27 patients, PFS16 rate was 37% (10/27; 95% CI: 19%-58%), thereby meeting the criteria for success for the primary endpoint. The median PFS and OS of the entire cohort were 3.9 months (95% CI: 2.5-7.4) and 9.1 months (95% CI: 8.0-14.3), respectively. In the patients evaluable for tumor response (n = 20), the ORR and DCR were 10% and 50%, respectively. Twenty patients (74.1%) had at least one grade 3 or worse adverse event (AE), and 4 patients (14.8%) had grade 4 AEs. A total of 37% (n = 10/27) and 51.9% (n = 14/27) experienced dose reductions in trifluridine/tipiracil and irinotecan, respectively. Delay in therapy was noted in 56% of the patients while 1 patient discontinued the therapy, primarily due to hematologic AEs. Conclusion The combination of trifluridine/tipiracil plus irinotecan is a potential treatment option for patients with advanced, refractory BTCs with good functional status and no targetable mutations. A larger randomized trial is needed to confirm these results. (ClinicalTrials.gov Identifier: NCT04072445)

Abstract Purpose: Although chemotherapy is standard of care for metastatic colorectal cancer (mCRC), immunotherapy has no role in microsatellite stable (MSS) mCRC, a “cold” tumor. PolyPEPI1018 is an off-the-shelf, multi-peptide vaccine derived from 7 tumor-associated antigens (TAA) frequently expressed in mCRC. This study assessed PolyPEPI1018 combined with first-line maintenance therapy in patients with MSS mCRC. Patients and Methods: Eleven patients with MSS mCRC received PolyPEPI1018 and Montanide ISA51VG adjuvant subcutaneously, combined with fluoropyrimidine/biologic following first-line induction with chemotherapy and a biologic (NCT03391232). In Part A of the study, 5 patients received a single dose; in Part B, 6 patients received up to three doses of PolyPEPI1018 every 12 weeks. The primary objective was safety; secondary objectives were preliminary efficacy, immunogenicity at peripheral and tumor level, and immune correlates. Results: PolyPEPI1018 vaccination was safe and well tolerated. No vaccine-related serious adverse event occurred. Eighty percent of patients had CD8+ T-cell responses against ≥3 TAAs. Increased density of tumor-infiltrating lymphocytes were detected post-treatment for 3 of 4 patients’ liver biopsies, combined with increased expression of immune-related gene signatures. Three patients had objective response according to RECISTv1.1, and 2 patients qualified for curative surgery. Longer median progression-free survival for patients receiving multiple doses compared with a single dose (12.5 vs. 4.6 months; P = 0.017) suggested a dose–efficacy correlation. The host HLA genotype predicted multi-antigen–specific T-cell responses (P = 0.01) indicative of clinical outcome. Conclusions: PolyPEPI1018 added to maintenance chemotherapy for patients with unresectable, MSS mCRC was safe and associated with specific immune responses and antitumor activity warranting further confirmation in a randomized, controlled setting.

4048 Background: PolyPEPI1018 is an off-the-shelf, multi-peptide vaccine containing 12 immunogenic epitopes derived from 7 cancer testis antigens (CTAs) frequently expressed in patients with CRC. Here we report the final results of the phase I study of PolyPEPI1018 vaccine as an add-on to maintenance therapy in mCRC patients. Methods: 11 patients with MSS mCRC were vaccinated with PolyPEPI1018 just after the transition to maintenance therapy with fluoropyrimidine/bevacizumab after first-line combo chemotherapy and bevacizumab. Part A: n = 5, single dose; Part B: n = 6, 3 doses, Q12W. Primary endpoint was safety. Immunomonitoring was performed at both blood and tumor levels, as well as prospectively predicted. Results: The vaccine was well tolerated; most common side effects were transient skin reactions. No vaccine-related SAE occurred. Pre-existing immune responses were boosted by the vaccine for 7/10 patients. De novo responses were also induced, overall, 80% of patients had CD8+ T cell responses against at least 3 CTAs. The magnitude of immune responses as well as the density and the ratio of CD8+/CD3+ tumor infiltrating T cells increased with multiple vaccine doses. Three patients had objective tumor response according to RECIST v1.1: one of them in the single dose group and two of them in the 3 doses group. Both patients in the 3 doses group qualified for curative surgery. One of them had no viable tumor cells in his primary tumor at the time of surgery. Post-trial follow-up revealed PFS of at least 12 months for 3 patients. mPFS was longer for patients receiving multiple doses (9.9 months) compared to single dose (6.1 months). Both measured and predicted multiantigenic immune responses tend to correlate with PFS and tumor volume reduction. Conclusions: PolyPEPI1018 was effective in restoring immunological responses to CTAs in patients’ with spontaneous immunity against. Treatment with PolyPEPI1018 vaccine and maintenance therapy was safe and demonstrated evidence of early clinical activity in MSS mCRC tumors. Data support further randomized trials with PolyPEPI1018. Clinical trial information: NCT03391232 .

TPS594 Background: Effective treatment options are very limited for patients with advanced refractory biliary tract cancer (BTC). Fluoropyrimidine-based chemotherapy regimen such as 5-fluorouracil and irinotecan are frequently utilized for these patients after first-line therapy despite lack of FDA approval. Trifluridine/tipiracil (FTD/TPI) is a novel oral nucleoside with antitumor activity in both fluoropyrimidine sensitive and resistant tumors due to its unique mechanisms of action. Given early toxicity and efficacy data from our previous study on single-agent trifluridine/tipiracil (FTD/TPI) in advanced BTC, the clinical evaluation of its combination with irinotecan represents a rational approach for the treatment of advanced refractory BTC. Methods: This is a single-arm phase II trial with a two-stage design to assess the efficacy of trifluridine/tipiracil (FTD/TPI) and irinotecan in advanced refractory BTC. Key eligibility criteria include histologically confirmed advanced, unresectable BTC who have progressed on at least one line of systemic therapy and have measurable disease per RECIST v1.1. Target accrual is 25. Treatment includes trifluridine/tipiracil (FTD/TPI) 25 mg/m2 on days 1-5 and irinotecan 180 mg/m2 on day 1 in 14-day cycles. Patients will be evaluated for response every 4 cycles and in the absence of disease progression, therapy may be given up to 2 years. The primary end point is the progression-free survival rate at 16 weeks. Secondary endpoints include overall response rate, disease control rate, progression-free survival, overall survival, and incidence of adverse events. Correlative biomarker studies include evaluations of circulating tumor DNA and circulating tumor cells at baseline, after 4 cycles and at progression; and development of patient-derived tumor organoids from pre-treatment biopsies for parallel treatments. This study was approved and funded in part by the National Comprehensive Cancer Network (NCCN) Oncology Research Program from general research support provided by Taiho Oncology, Inc. Clinical trial information: NCT 04072445.

AbstractTrial InformationClick here to access other published clinical trials.Lessons LearnedTrifluridine/tipiracil (FTD/TPI) shows promising antitumor activity in heavily pretreated patients with advanced biliary tract carcinoma, including patients with 5-fluorouracil refractory tumors. FTD/TPI has an acceptable safety profile and should be studied further in patients with advanced biliary tract carcinoma after progression on standard first-line therapy.BackgroundPatients with advanced biliary tract carcinoma (BTC) refractory to first-line therapy lack an established second-line option. Trifluridine/tipiracil (FTD/TPI) has activity in both fluoropyrimidine-sensitive and -resistant tumors, which led us to conduct a single arm phase II trial to evaluate the safety and efficacy of FTD/TPI for patients previously treated for advanced BTC.MethodsPatients with advanced BTC previously treated with at least one line of chemotherapy were enrolled and treated with FTD/TPI until disease progression or unacceptable toxicity. The primary endpoint target was to have at least 6 patients who were progression free and alive at 16 weeks among 25 evaluable patients. Secondary endpoints included overall survival (OS), overall response rate (ORR), progression-free survival (PFS), and toxicity.ResultsOf 27 evaluable patients, 59.3% received at least three prior lines of therapy, and 81.5% had previous exposure to fluoropyrimidine. Eight (32%, 95% confidence interval [CI], 14.9%–53.5%) patients were progression free at 16 weeks in the primary analysis population (n = 25), which met the predefined efficacy criteria. Median PFS and OS were 3.8 (95% CI, 2–5.8 months) and 6.1 (95% CI, 4.4–11.4 months) months, respectively. No objective responses were seen. There were no unexpected safety signals noted.ConclusionFTD/TPI demonstrated promising antitumor activity, with acceptable toxicity, in heavily pretreated patients with advanced BTC.

3557 Background: The goal of this study was to evaluate the safety, tolerability and immunogenicity of a single dose of PolyPEPI1018 as an add-on to maintenance therapy in subjects with metastatic colorectal cancer (mCRC). PolyPEPI1018 is a peptide vaccine containing 12 unique epitopes derived from 7 conserved cancer testis antigens (CTAs) frequently expressed in mCRC. These epitopes were designed to be Personal EPItopes (PEPIs), i.e. predicted by our novel PEPI test to bind to at least three autologous HLA alleles and more likely to induce T-cell responses than epitopes presented by a single HLA. Methods: mCRC patients in the first line setting received the vaccine (dose: 0.2 mg/peptide) just after the transition to maintenance therapy with a fluoropyrimidine and bevacizumab. Vaccine-specific T-cell responses were first predicted by the PEPI test (using the patient’s complete HLA genotype and antigen expression rate) and then measured by ELISpot after one cycle of vaccination. Results: Eleven patients were vaccinated with PolyPEPI1018. The most common adverse events were transient skin reactions (local inflammation at the site of the injections, e.g. erythema, redness and itchiness) and flu-like syndrome. No grade 3 or higher adverse events related to the vaccine occurred. Initial analysis on 4 patients demonstrated that T-cell responses were elicited by 96% of vaccine peptides. The overall percentage agreement between PEPI test-predicted and Elispot-measured CD8+ T cell responses was 71%, consistent with our retrospective analysis on 64 vaccine clinical trials involving 1,790 patients. Two of these 4 patients had unexpected tumor size reduction. Based on these encouraging results, the trial was amended to administer 3 doses of PolyPEPI1018 given 12 weeks apart. Conclusions: PolyPEPI1018 combined with maintenance therapy was safe and well-tolerated in mCRC patients. Unprecedented immune responses were induced after single dose, with broad CRC-specific T cell responses and high accuracy prediction of CD8+ T cell responses. This promising activity in mCRC patients led to a trial amendment to administer 3 doses of PolyPEPI1018 in combination with systemic therapy. Clinical trial information: NCT03391232.