Programmed death 1 (PD-1) blockade has clinical benefit in microsatellite-instability–high (MSI-H) or mismatch-repair–deficient (dMMR) tumors after previous therapy. The efficacy of PD-1 blockade as compared with chemotherapy as first-line therapy for MSI-H–dMMR advanced or metastatic colorectal cancer is unknown.

Abdominoperineal resection is the standard treatment for patients with distal T2 or T3 rectal cancers; however, the procedure is extensive and mutilating, and alternative treatment strategies are being investigated. We did a prospective observational trial to assess whether high-dose radiotherapy with concomitant chemotherapy followed by observation (watchful waiting) was successful for non-surgical management of low rectal cancer. Patients with primary, resectable, T2 or T3, N0-N1 adenocarcinoma in the lower 6 cm of the rectum were given chemoradiotherapy (60 Gy in 30 fractions to tumour, 50 Gy in 30 fractions to elective lymph node volumes, 5 Gy endorectal brachytherapy boost, and oral tegafur-uracil 300 mg/m(2)) every weekday for 6 weeks. Endoscopies and biopsies of the tumour were done at baseline, throughout the course of treatment (weeks 2, 4, and 6), and 6 weeks after the end of treatment. We allocated patients with complete clinical tumour regression, negative tumour site biopsies, and no nodal or distant metastases on CT and MRI 6 weeks after treatment to the observation group (watchful waiting). We referred all other patients to standard surgery. Patients under observation were followed up closely with endoscopies and selected-site biopsies, with surgical resection given for local recurrence. The primary endpoint was local tumour recurrence 1 year after allocation to the observation group. This study is registered with ClinicalTrials.gov, number NCT00952926. Enrolment is closed, but follow-up continues for secondary endpoints. Between Oct 20, 2009, and Dec 23, 2013, we enrolled 55 patients. Patients were recruited from three surgical units throughout Denmark and treated in one tertiary cancer centre (Vejle Hospital, Vejle, Denmark). Of 51 patients who were eligible, 40 had clinical complete response and were allocated to observation. Median follow-up for local recurrence in the observation group was 23·9 months (IQR 15·3-31·0). Local recurrence in the observation group at 1 year was 15·5% (95% CI 3·3-26·3). The most common acute grade 3 adverse event during treatment was diarrhoea, which affected four (8%) of 51 patients. Sphincter function in the observation group was excellent, with 18 (72%) of 25 patients at 1 year and 11 (69%) of 16 patients at 2 years reporting no faecal incontinence at all and a median Jorge-Wexner score of 0 (IQR 0-0) at all timepoints. The most common late toxicity was bleeding from the rectal mucosa; grade 3 bleeding was reported in two (7%) in 30 patients at 1 year and one (6%) of 17 patients at 2 years. There were no unexpected serious adverse reactions or treatment-related deaths. High-dose chemoradiotherapy and watchful waiting might be a safe alternative to abdominoperineal resection for patients with distal rectal cancer. CIRRO-The Lundbeck Foundation Center for Interventional Research in Radiation Oncology and The Danish Council for Strategic Research.

Patients with microsatellite-instability-high (MSI-H) or mismatch-repair-deficient (dMMR) metastatic colorectal cancer have poor outcomes with standard chemotherapy with or without targeted therapies. Nivolumab plus ipilimumab has shown clinical benefit in nonrandomized studies of MSI-H or dMMR metastatic colorectal cancer. In this phase 3 open-label trial, we randomly assigned patients with unresectable or metastatic colorectal cancer and MSI-H or dMMR status according to local testing to receive, in a 2:2:1 ratio, nivolumab plus ipilimumab, nivolumab alone, or chemotherapy with or without targeted therapies. The dual primary end points, assessed in patients with centrally confirmed MSI-H or dMMR status, were progression-free survival with nivolumab plus ipilimumab as compared with chemotherapy as first-line therapy and progression-free survival with nivolumab plus ipilimumab as compared with nivolumab alone in patients regardless of previous systemic treatment for metastatic disease. At this prespecified interim analysis, the first primary end point (involving nivolumab plus ipilimumab vs. chemotherapy) was assessed. A total of 303 patients who had not previously received systemic treatment for metastatic disease were randomly assigned to receive nivolumab plus ipilimumab or chemotherapy; 255 patients had centrally confirmed MSI-H or dMMR tumors. At a median follow-up of 31.5 months (range, 6.1 to 48.4), progression-free survival outcomes (the primary analysis) were significantly better with nivolumab plus ipilimumab than with chemotherapy (P<0.001 for the between-group difference in progression-free survival, calculated with the use of a two-sided stratified log-rank test); 24-month progression-free survival was 72% (95% confidence interval [CI], 64 to 79) with nivolumab plus ipilimumab as compared with 14% (95% CI, 6 to 25) with chemotherapy. At 24 months, the restricted mean survival time was 10.6 months (95% CI, 8.4 to 12.9) longer with nivolumab plus ipilimumab than with chemotherapy, a finding consistent with the primary analysis of progression-free survival. Grade 3 or 4 treatment-related adverse events occurred in 23% of the patients in the nivolumab-plus-ipilimumab group and in 48% of the patients in the chemotherapy group. Progression-free survival was longer with nivolumab plus ipilimumab than with chemotherapy among patients who had not previously received systemic treatment for MSI-H or dMMR metastatic colorectal cancer. (Funded by Bristol Myers Squibb and Ono Pharmaceutical; CheckMate 8HW ClinicalTrials.gov number, NCT04008030.).

Despite complete resection, disease-free survival (DFS) of patients with cholangiocarcinoma (CCA) is less than 65 % after one year and not more than 35 % after three years. For muscle invasive gallbladder carcinoma (GBCA), prognosis is even worse, with an overall survival (OS) of only 30 % after three years. Thus, evaluation of adjuvant chemotherapy in biliary tract cancer in a large randomized trial is warranted. ACTICCA-1 is a randomized, multidisciplinary, multinational phase III investigator initiated trial. With respect to data obtained in the ABC-02 trial, we selected the combination of gemcitabine and cisplatin for 24 weeks as investigational treatment. Based on adjuvant trials in pancreatic cancer with comparable postoperative recovery time, inclusion of patients within a maximum interval of 16 weeks between surgery and start of chemotherapy was stipulated. Due to the different prognosis and treatment susceptibility of muscle invasive carcinoma, two separate cohorts (CCA and GBCA) were included to capture the potentially different treatment effects. Randomization is stratified for lymph node status for both cohorts and localization for CCA. The primary endpoint is DFS and secondary endpoints include OS, safety and tolerability of chemotherapy, quality of life, and patterns of disease recurrence. For CCA, adjuvant chemotherapy should increase DFS 24 months post-surgery from 40 to 55 % to be considered relevant. With a power of 80 % and a significance level of 5 %, 271 evaluable study patients have to be followed for 24–28 months to observe 166 events. For GBCA, chemotherapy should increase DFS 24 months post-surgery from 35 to 55 % to be of relevance; thus, 154 evaluable study patients have to be monitored for 24–28 months to observe 90 events. In both cohorts, randomization will be 1:1 with chemotherapy for 24 weeks and imaging every twelve weeks. In 2014, the study was initiated in Germany and in The Netherlands (funded by the Deutsche Krebshilfe, the Dutch Cancer Society, and supported by medac GmbH). Sites in Australia, Denmark, and the United Kingdom (funded by Cancer Research UK) are joining 2015. The study is registered with ClinicalTrials.gov ( NCT02170090 ) and the European Clinical Trials Database (2012-005078-70). Registration date is 06/18/2014.