Bekaii-Saab, Tanios S

PURPOSE Recent advances in molecular diagnostic technologies have allowed for the evaluation of solid tumor malignancies via noninvasive blood sampling, including circulating tumor DNA (ctDNA) profiling. We sought to characterize the ctDNA genomic alteration landscape in patients with biliary tract cancers (BTCs). PATIENTS AND METHODS From January 2015 to February 2018, 124 patients with BTC at the Mayo Clinic Comprehensive Cancer Center underwent ctDNA testing using a clinically available assay. The majority of samples (n = 122) were tested using the 73-gene panel that includes somatic genomic targets, including complete or critical exon coverage in 30 and 40 genes, respectively, and in some, amplifications, fusions, and indels. RESULTS A total of 138 samples were included, with approximately 70% of patients having intrahepatic BTC. All patients had locally advanced or metastatic BTC. Samples with one or more alterations, when variants of unknown significance were excluded, numbered 105 (76%). Each sample contained, on average, three alterations with a median allelic fraction of 0.52%. The overall landscape of alterations is summarized in Figures 1 and 2. After excluding variants of unknown significance, therapeutically relevant alterations were observed in 76 patients (55%), including BRAF mutations, ERBB2 amplifications, FGFR2 fusions, FGFR2 mutations, and IDH1 mutations seen in 21% of patients. A different spectrum of alterations was observed in patients with early-onset BTC (younger than age 50 years) compared with older patients (older than age 50 years). CONCLUSION Data on ctDNA in BTC is currently limited. Our study, the largest cohort reported to date to our knowledge, demonstrates the feasibility of ctDNA testing in this disease. We provide a foundation upon which the field can continue to grow.

Cancer stem cells (CSCs) are thought to be a distinct population of cells within a tumor mass that are capable of asymmetric division and known to have chemoresistant characteristics. The description and identification of CSC models in cancer growth and recurrence has inspired the design of novel treatment strategies to overcome treatment resistance by targeting both CSCs and non-CSC tumor cells. Several cellular signaling pathways have been described as playing a role in the induction and maintenance of stemness in CSCs, such as the Wnt/β-catenin, Notch, STAT3, and Hedgehog pathways. In this review, we aim to review some of the ongoing CSC therapeutic targeting strategies in gastrointestinal malignancies.

PURPOSE To develop an evidence-based clinical practice guideline to assist in clinical decision making for patients with resected biliary tract cancer. METHODS ASCO convened an Expert Panel to conduct a systematic review of the literature on adjuvant therapy for resected biliary tract cancer and provide recommended care options for this patient population. RESULTS Three phase III randomized controlled trials, one phase II trial, and 16 retrospective studies met the inclusion criteria. RECOMMENDATIONS Based on evidence from a phase III randomized controlled trial, patients with resected biliary tract cancer should be offered adjuvant capecitabine chemotherapy for a duration of 6 months. The dosing used in this trial is described in the qualifying statements, while it should be noted that the dose of capecitabine may also be determined by institutional and regional practices. Patients with extrahepatic cholangiocarcinoma or gallbladder cancer and a microscopically positive surgical resection margin (R1 resection) may be offered chemoradiation therapy. A shared decision-making approach is recommended, considering the risk of harm and potential for benefit associated with radiation therapy for patients with extrahepatic cholangiocarcinoma or gallbladder cancer. Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines .

Abstract Purpose: This first-in-human phase I study (NCT 01417546) evaluated the safety profile, optimal immunologic/biological dose (OID/OBD), and immunogenicity of the combination of two peptide B-cell epitope vaccines engineered to represent the trastuzumab- and pertuzumab-binding sites. Although trastuzumab and pertuzumab have been approved for clinical use, patients often develop resistance to these therapies. We have advanced a new paradigm in immunotherapy that focuses on humoral responses based on conformational B-cell epitope vaccines. Patients and Methods: The vaccine is comprised of two chimeric HER-2 B-cell peptide vaccines incorporating a “promiscuous T-cell epitope.” Patients were immunized with the vaccine constructs emulsified with nor-muramyl-dipeptide adjuvant in a water-in-oil Montanide ISA 720VG vehicle. Eligible patients with metastatic and/or recurrent solid tumors received three inoculations every 3 weeks. Results: Forty-nine patients with a median of 4 prior lines of chemotherapy received at least 1 vaccination. Twenty-eight patients completed the 3 vaccination regimens. Six patients received 1 six-month boost after the regimen, and one patient received 7 six-month boosts. No serious adverse reactions or dose-limiting toxicities were observed. The vaccine was well tolerated with dose level 2 as the recommended phase II dose. The most common related toxicity in all patients was injection-site reactions (24%). Two patients had a partial response, 14 had stable disease, and 19 had progressive disease. Conclusions: The study vaccine is safe, exhibits antitumor activity, and shows preliminary indication that peptide vaccination may avoid therapeutic resistance and offer a promising alternative to monoclonal antibody therapies.

Abstract Purpose: This first-in-human, open-label phase I study evaluated AMG 337, an oral, highly selective small-molecule inhibitor of MET in advanced solid tumors. Patients and Methods: Patients enrolled into dose-escalation cohorts received AMG 337 up to 400 mg once daily or up to 250 mg twice daily, following a modified 3+3+3 design. Dose expansion was conducted in MET-amplified patients at the maximum tolerated dose (MTD). Primary endpoints included assessment of adverse events (AEs), establishment of the MTD, and pharmacokinetics; clinical response was a secondary endpoint. Results: The safety analysis set included 111 patients who received ≥1 dose of AMG 337. Thirteen patients had ≥1 AE qualifying as dose-limiting toxicity. The MTD was determined to be 300 mg once daily; the MTD for twice-daily dosing was not reached. Most frequent treatment-related AEs were headache (63%) and nausea (31%). Grade ≥3 treatment-related AEs occurred in 23 patients (21%), most commonly headache (n = 6) and fatigue (n = 5). Maximum plasma concentration occurred at 3.0 hours following 300-mg once-daily dosing, indicating AMG 337 absorption soon after treatment. Objective response rate was 9.9% (11/111; 95% CI, 5.1%–17.0%) in all patients and 29.6% (8/27; 95% CI, 13.8%–50.2%) in MET-amplified patients; median (range) duration of response was 202 (51–1,430+) days in all patients and 197 (64–1,430+) days in MET-amplified patients. Conclusions: Oral AMG 337 was tolerated with manageable toxicities, with an MTD and recommended phase II dose of 300 mg once daily. The promising response rate observed in patients with heavily pretreated MET-amplified tumors warrants further investigation. See related commentary by Ma, p. 2375

Abstract Colorectal carcinoma is the third most common cancer worldwide. Approximately 20% of patients with colorectal cancer will have metastatic disease at the time of initial diagnosis, and approximately 30% to 50% of patients with primary colon cancer will relapse and die of metastatic cancer. The 5-year survival rate of metastatic colorectal cancer remains disappointing at approximately 10%. Angiogenesis plays a significant role in tumor growth and metastasis in colorectal carcinoma. There are currently 4 US Food and Drug Administration–approved antiangiogenic agents for metastatic colorectal cancer. Bevacizumab is the only antiangiogenic agent approved by the US Food and Drug Administration for first-line treatment of metastatic colorectal cancer. Other antiangiogenic agents include ramucirumab, ziv-aflibercept, and regorafenib. We review the data supporting the use of antiangiogenics in this disease.