Phase II study to determine the anti-tumor activity and safety of simlukafusp alfa (FAP-IL2v) combined with atezolizumab in esophageal cancer.

PURPOSE: Reported here are results from the esophageal squamous cell carcinoma (SCC) cohort of a Phase II, non-comparative, basket study, evaluating the anti-tumor activity and safety of FAP-IL2v plus atezolizumab in patients with advanced/metastatic solid tumors (NCT03386721). EXPERIMENTAL DESIGN: Eligible patients had an Eastern Cooperative Oncology Group performance status of 0-1; measurable metastatic, persistent, or recurrent esophageal SCC; progression on ≥1 prior therapy; and were checkpoint inhibitor naive. Patients received FAP-IL2v 10 mg plus atezolizumab 1200 mg intravenously every 3 weeks, or FAP-IL2v weekly for 4 weeks, then every 2 weeks, plus atezolizumab 840 mg intravenously every 2 weeks. Primary endpoint was investigator-assessed objective response rate (ORR). RESULTS: In the response-evaluable population (N=34), best confirmed ORR was 20.6% (95% confidence interval [CI]: 10.4-36.8) with a complete response (CR) seen in one patient and partial responses (PR) in six patients. Disease control rate was 44.1% (CR=2.9%; PR=17.6%; stable disease [SD]=23.5%) and median duration of response was 10.1 months (95% CI: 5.6-26.7). Median progression-free survival was 1.9 months (95% CI: 1.8-3.7). Analysis of response by PD-L1 expression (Ventana SP263) resulted in an ORR of 26.7 % for patients with PD-L1-positive tumors (tumor area positivity [TAP] cut-off ≥1%; n=15) and 7.1% for patients with PD-L1-negative tumors (TAP cut-off <1%; n=14). Overall, the treatment combination was tolerable and adverse events were consistent with the known safety profiles of each drug. CONCLUSIONS: FAP-IL2v plus atezolizumab demonstrated clinical activity and was tolerable in patients with previously treated esophageal SCC.

Oral PD-L1 inhibitor GS-4224 selectively engages PD-L1 high cells and elicits pharmacodynamic responses in patients with advanced solid tumors.

BACKGROUND: Checkpoint inhibitors targeting the programmed cell death 1 (PD-1)/programmed cell death 1 ligand 1 (PD-L1) pathway are effective therapies in a range of immunogenic cancer types. Blocking this pathway with an oral therapy could benefit patients through greater convenience, particularly in combination regimens, and allow flexible management of immune-mediated toxicities. METHODS: PD-L1 binding activity was assessed in engineered dimerization and primary cell target occupancy assays. Preclinical antitumor activity was evaluated in ex vivo and in vivo human PD-L1-expressing tumor models. Human safety, tolerability, pharmacokinetics, and biomarker activity were evaluated in an open-label, multicenter, sequential dose-escalation study in patients with advanced solid tumors. Biomarkers evaluated included target occupancy, flow cytometric immunophenotyping, plasma cytokine measurements, and T-cell receptor sequencing. RESULTS: GS-4224 binding caused dimerization of PD-L1, blocking its interaction with PD-1 and leading to reversal of T-cell inhibition and increased tumor killing in vitro and in vivo. The potency of GS-4224 was dependent on the density of cell surface PD-L1, with binding being most potent on PD-L1-high cells. In a phase 1 dose-escalation study in patients with advanced solid tumors, treatment was well tolerated at doses of 400-1,500 mg once daily. Administration of GS-4224 was associated with a dose-dependent increase in plasma GS-4224 exposure and reduction in free PD-L1 on peripheral blood T cells, an increase in Ki67 among the PD-1-positive T-cell subsets, and elevated plasma cytokines and chemokines. CONCLUSIONS: GS-4224 is a novel, orally bioavailable small molecule inhibitor of PD-L1. GS-4224 showed evidence of expected on-target biomarker activity, including engagement of PD-L1 and induction of immune-related pharmacodynamic responses consistent with PD-L1 blockade. TRIAL REGISTRATION NUMBER: NCT04049617.

Real-world outcomes of cisplatin, capecitabine, and gemcitabine with either epirubicin (PEXG) or docetaxel (PDXG) as first-line palliative treatment in metastatic or unresectable locally advanced pancreatic adenocarcinoma.

BACKGROUND: First-line palliative chemotherapy regimens in advanced pancreatic adenocarcinoma include triplet chemotherapy with 5-fluorouracil, oxaliplatin, and irinotecan, and the doublet of nab-paclitaxel plus gemcitabine. Use of triplet chemotherapy in real-world populations is limited by tolerability and nab-paclitaxel is not universally available. Regimens using the combination of cisplatin, capecitabine, gemcitabine, and either epirubicin or docetaxel may be better tolerated, more widely available, and similarly effective, but no published real-world data exist. METHODS: A retrospective cohort review of patients with metastatic or unresectable locally advanced pancreatic adenocarcinoma treated with first-line palliative cisplatin, capecitabine, gemcitabine, and either epirubicin or docetaxel chemotherapy at Auckland City Hospital between July 1, 2013 and July 30, 2020. The primary outcome was overall survival (OS). Secondary outcomes were rates of grade 3 or 4 hematological toxicity, rate of febrile neutropenia, number of cycles received, and reasons for discontinuation. RESULTS: Eighty-eight patients were included. Median age was 66 years (range 39-79), 28.4% had unresectable, locally advanced disease and 71.6% metastatic disease. Median OS was 8.5 months. Patients stopped treatment due to disease progression (53.4%), completing 12 cycles (19.3%), or toxicity (10.2%). Grade 4 neutropenia was experienced by 21.6%; 10.2% had febrile neutropenia. There were four treatment-related deaths. CONCLUSION: This retrospective study in a real-world population demonstrates that chemotherapy with cisplatin, capecitabine, and gemcitabine with epirubicin (PEXG) or docetaxel (PDXG) had similar effectiveness to more commonly used combination regimens. PDXG/PEXG are viable alternatives to nab-paclitaxel plus gemcitabine in countries that have restricted drug funding.

Response to BRAF-targeted Therapy Is Enhanced by Cotargeting VEGFRs or WNT/ß-Catenin Signaling in BRAF-mutant Colorectal Cancer Models.

The fact that 10% of colorectal cancer tumors harbor BRAF V600E mutations suggested targeting BRAF as a potential therapy. However, BRAF inhibitors have only limited single-agent efficacy in this context. The potential for combination therapy has been shown by the BEACON trial where targeting the EGF receptor with cetuximab greatly increased efficacy of BRAF inhibitors in BRAF-mutant colorectal cancer. Therefore, we explored whether efficacy of the mutant BRAF inhibitor vemurafenib could be enhanced by cotargeting of either oncogenic WNT/ß-catenin signaling or VEGFR signaling. We find the WNT/ß-catenin inhibitors pyrvinium, ICG-001 and PKF118-310 attenuate growth of colorectal cancer cell lines in vitro with BRAF-mutant lines being relatively more sensitive. Pyrvinium combined with vemurafenib additively or synergistically attenuated growth of colorectal cancer cell lines in vitro. The selective and potent VEGFR inhibitor axitinib was most effective against BRAF-mutant colorectal cancer cell lines in vitro, but the addition of vemurafenib did not significantly increase these effects. When tested in vivo in animal tumor models, both pyrvinium and axitinib were able to significantly increase the ability of vemurafenib to attenuate tumor growth in xenografts of BRAF-mutant colorectal cancer cells. The magnitude of these effects was comparable with that induced by a combination of vemurafenib and cetuximab. This was associated with additive effects on release from tumor cells and tumor microenvironment cell types of substances that would normally aid tumor progression. Taken together, these preclinical data indicate that the efficacy of BRAF inhibitor therapy in colorectal cancer could be increased by cotargeting either WNT/ß-catenin or VEGFRs with small-molecule inhibitors.

The combination of gene hyperamplification and PD-L1 expression as a biomarker for the clinical benefit of tislelizumab in gastric/gastroesophageal junction adenocarcinoma.

BACKGROUND: In solid tumor Phase 1/2 trials (NCT02407990; NCT04068519), tislelizumab demonstrated clinical benefit, including in advanced gastroesophageal adenocarcinoma (GEA). However, the majority of patients with GEA did not respond, highlighting the need to understand mechanisms of resistance and identify predictive biomarkers for response. METHODS: All tislelizumab-treated patients with GEA from the Phase 1/2 trials were included (N = 105). Programmed death-ligand 1 (PD-L1) expression (Tumor Area Positivity [TAP] ≥ 5%), interferon gamma (IFNγ)-related gene signature, gene expression profile, tumor mutational burden (TMB), and gene hyperamplification (HA) were analyzed for correlation with tislelizumab. RESULTS: A moderate association was observed between PD-L1 TAP ≥ 5%, IFNγ gene signature, TMB-high and efficacy. A potential correlation between hyperamplification (HA +) and worse outcomes with programmed cell death protein 1 (PD-1) inhibition was identified. Hyperamplified genes were mainly enriched in cancer progression pathways, including cell cycle and RTK-RAS-PI3K pathways. Joint PD-L1 TAP ≥ 5% and lack of hyperamplification showed the most favorable benefit with an objective response rate of 29.4%, and median progression-free survival and overall survival of 4.1 and 14.7 months, respectively. Tumors with TAP ≥ 5% and HA - had inflamed immune signatures with increased immune cell infiltration, enhanced anti-tumor cytotoxic activity and antigen presentation signatures. Findings were validated in two independent gastric and gastrointestinal cancer cohorts treated with immune checkpoint inhibitors. CONCLUSIONS: In GEA, PD-L1 positivity, IFNγ-related gene signature and TMB-high status were positively associated with tislelizumab clinical benefit, whereas HA was associated with worse clinical outcomes. Combining PD-L1 positivity and HA - may help identify patients more likely to benefit from PD-1 blockade.

Population pharmacokinetics for oral paclitaxel in patients with advanced/metastatic solid tumors.

Oraxol consists of an oral dosage form of the chemotherapeutic agent paclitaxel administered with a novel P-glycoprotein inhibitor encequidar methanesulfonate monohydrate (formerly named HM30181A), which allows oral treatment of cancers that would otherwise be treated with intravenous paclitaxel. Here we describe the population pharmacokinetics (popPK) analyses for oral paclitaxel in patients with advanced/metastatic solid tumors to characterize pharmacokinetic (PK) profiles and quantify sources of PK variability. The best fit popPK model for oral paclitaxel, based on data from seven clinical studies (197 patients with advanced/metastatic solid tumors), involves a linear two-compartment structural model containing first-order absorption with a short lag time and first-order elimination as well as a log additive error. In this popPK model, lower population estimates of central volume for Asian patients versus Caucasian patients did not translate into clinical meaningful differences in oral paclitaxel exposure. Age, sex, body weight or surface area, mild hepatic impairment, and mild to moderate renal impairment had no clinically meaningful effects on the systemic exposure of oral paclitaxel. Simulations were performed on clinical therapeutic dose (oral paclitaxel 205 mg/m2 once daily ×3 days per week) to predict exposure of oral paclitaxel and to support treatment benefits observed in a pivotal phase III trial.

Intralesional SD-101 in Combination with Pembrolizumab in Anti-PD-1 Treatment-Naïve Head and Neck Squamous Cell Carcinoma: Results from a Multicenter, Phase II Trial.

PURPOSE: To determine whether SD-101, a Toll-like receptor 9 agonist, potentiates the antitumor activity of anti-PD-1 antibodies in patients with anti-PD-1/PD-L1 naïve, recurrent/metastatic head and neck squamous cell carcinoma (HNSCC). PATIENTS AND METHODS: Patients with PD-1 Ab-naïve HNSCC received either 2 mg SD-101 injected in one to four lesions or 8 mg SD-101 injected into a single lesion weekly × 4 doses then every 3 weeks × 7 doses. Pembrolizumab was administered at 200 mg every 3 weeks. RESULTS: A total of 28 patients received 2 mg and 23 received 8 mg per injection, respectively. A total of 76% of patients had received prior systemic therapy. Combined positive score was ≥1 to < 20 in 35 patients (70%) and ≥ 20 in 15 patients (30%) of 50 patients with available data. There were 12 patients with grade ≥3 treatment-related adverse events (24%), and no treatment-related deaths. The objective response rate was 24% including 2 complete and 10 partial responses. The median duration of response was 7.0 [95% confidence interval (CI): 2.1-11.1] months. The response rate was higher in human papillomavirus-positive (HPV+) patients (44%, N = 16). Responses were not associated with PD-L1 expression levels or IFNγ-related gene expression at baseline. Responses were observed both in injected (32%) and in noninjected lesions (29%). Progression-free and overall survival at 9 months were 19.0% (95% CI: 9.1-31.7) and 64.7% (95% CI: 45.3-78.7), respectively. CONCLUSIONS: SD-101 combined with pembrolizumab induced objective responses, especially in HPV+ tumors, which were frequently associated with increased intratumoral inflammation and effector immune cell activity.

Oral paclitaxel with encequidar compared to intravenous paclitaxel in patients with advanced cancer: A randomised crossover pharmacokinetic study.

AIMS: Paclitaxel is a widely used anti-neoplastic agent but has low oral bioavailability due to gut extrusion by P-glycoprotein (P-gp). Oral paclitaxel could be more convenient, less resource intensive, and more tolerable than intravenous administration. Encequidar (HM30181A) is a novel, minimally absorbed gut-specific P-gp inhibitor. We tested whether administration of oral paclitaxel with encequidar (oPac+E) achieved comparable AUC to intravenous paclitaxel (IVP) 80 mg/m2 . METHODS: We conducted a multi-centre randomised crossover study with two treatment periods. Patients (pts) with advanced cancer received either oral paclitaxel 615 mg/m2 divided over 3 days and encequidar 15 mg orally 1 hour prior, followed by IVP 80 mg/m2 , or the reverse sequence. PK blood samples were taken up to Day 9 for oPac+E and Day 5 for IVP. RESULTS: Forty-two patients were enrolled; 35 completed both treatment periods. AUC0-∞ was 5033.5 ± 1401.1 ng.h/mL for oPac+E and 5595.9 ± 1264.1 ng.h/mL with IVP. The geometric mean ratio (GMR) for AUC was 89.50% (90% CI 83.89-95.50). Mean absolute bioavailability of oPac+E was 12% (CV% = 23%). PK parameters did not change meaningfully after 4 weeks administration of oPac+E in an extension study. G3 treatment-emergent adverse events occurred in seven (18%) pts with oPac+E and two (5%) with IVP. Seventy-five per cent of patients preferred oPac+E over IVP. CONCLUSIONS: GMR for AUC was within the predefined acceptable range of 80-125% for demonstrating equivalence. oPac+E is tolerable and there is no evidence of P-gp induction with repeat administration. With further study, oPac+E could be an alternative to IVP.

Cardiac Troponin I and T in Checkpoint Inhibitor-associated Myositis and Myocarditis.

Checkpoint inhibitor-associated myocarditis (ir-myocarditis) and myositis (ir-myositis) may occur concurrently among patients on checkpoint inhibitor immunotherapy. While cardiac-specific troponin I (cTnI) and troponin T (cTnT) are regarded to have similar sensitivities and specificities in conditions such as acute coronary syndrome, the cardiac specificity of cTnT has been challenged following observation that patients with neuromuscular diseases, including myositis, may have elevated cTnT without apparent clinical evidence of myocardial injury. Consequently, in the context of concurrent ir-myositis, cTnI may be a more appropriate biomarker for diagnosing and monitoring ir-myocarditis. To illustrate this point, we report a case of a patient with severe ir-myositis while on adjuvant programmed cell death protein 1 inhibitor immunotherapy for stage III melanoma, with accompanying elevation in cTnT.

Phase IA/IB study of single-agent tislelizumab, an investigational anti-PD-1 antibody, in solid tumors.

BACKGROUND: The programmed cell death-1/programmed cell death ligand-1 (PD-1/PD-L1) axis plays a central role in suppressing antitumor immunity; axis dysregulation can be used by cancer cells to evade the immune system. Tislelizumab, an investigational monoclonal antibody with high affinity and binding specificity for PD-1, was engineered to minimize binding to FcγR on macrophages to limit antibody-dependent phagocytosis, a potential mechanism of resistance to anti-PD-1 therapy. The aim of this phase IA/IB study was to investigate the safety/tolerability, antitumor effects and optimal dose and schedule of tislelizumab in patients with advanced solid tumors. METHODS: Patients (aged ≥18 years) enrolled in phase IA received intravenous tislelizumab 0.5, 2, 5 or 10 mg/kg every 2 weeks; 2 or 5 mg/kg administered every 2 weeks or every 3 weeks; or 200 mg every 3 weeks; patients in phase IB received 5 mg/kg every 3 weeks. Primary objectives were to assess tislelizumab's safety/tolerability profile by adverse event (AE) monitoring and antitumor activity using RECIST V.1.1. PD-L1 expression was assessed retrospectively with the VENTANA PD-L1 (SP263) Assay. RESULTS: Between May 2015 and October 2017, 451 patients (n=116, IA; n=335, IB) were enrolled. Fatigue (28%), nausea (25%) and decreased appetite (20%) were the most commonly reported AEs. Most AEs were grade 1-2 severity; anemia (4.9%) was the most common grade 3-4 AE. Treatment-related AEs led to discontinuation in 5.3% of patients. Grade 5 AEs were reported in 14 patients; 2 were considered related to tislelizumab. Pneumonitis (2%) and colitis (1%) were the most common serious tislelizumab-related AEs. As of May 2019, 18% of patients achieved a confirmed objective response in phase IA and 12% in phase IB; median follow-up duration was 13.6 and 7.6 months, respectively. Pharmacokinetics, safety and antitumor activity obtained from both phase IA and IB determined the tislelizumab recommended dose; ultimately, tislelizumab 200 mg intravenous every 3 weeks was the dose and schedule recommended to be taken into subsequent clinical trials. CONCLUSIONS: Tislelizumab monotherapy demonstrated an acceptable safety/tolerability profile. Durable responses were observed in heavily pretreated patients with advanced solid tumors, supporting the evaluation of tislelizumab 200 mg every 3 weeks, as monotherapy and in combination therapy, for the treatment of solid tumors and hematological malignancies. TRIAL REGISTRATION NUMBER: NCT02407990.

Mortality within 30 days of systemic anticancer therapy at a tertiary cancer centre: assessing the safety and quality of clinical care.

AIMS: Thirty-day mortality has been proposed to be a useful indicator of avoidable harm to patients from systemic anticancer therapies (SACT). As a quality assurance tool, we assessed the 30-day mortality rate at Auckland City Hospital and compared this with international standards. METHODS: Clinical characteristics and treatment details of medical oncology patients who died within 30 days of SACT from October 2014-September 2015 were collected and compared with data from a similar series performed from October 2008-September 2009. SACT was limited to chemotherapy or biologic agents. RESULTS: From October 2014-September 2015, 1,965 patients received 2,145 treatment regimens. Forty-seven patients (2.2%) died within 30 days of SACT. Treatment was given with palliative intent in 42 patients (in 89%) and curative intent in five (11%). Mortality rates did not change with time (2.8% in 2009 vs 2.2% in 2015). Of the patient who died within 30 days, ECOG performance status at the time of chemotherapy was one in 16 patients (34.0%), two in nine patients (19.1%) and 3/4 in nine of the 47 patients (19.1%). All patients treated with curative intent had a PS of 0 or 1. Most patients who died within 30 days were on first- or second-line therapy (45 and 38% respectively). Two-thirds of patients with a PS of 3/4 were receiving first-line therapy. Approximately half the patients died during their first cycle of therapy (48.9%). CONCLUSIONS: Our local 30-day mortality data compares favourably to international benchmarks of 5% and has not increased over time. Performance of similar studies locally and nationally should be undertaken to continue to assess and improve the quality of our patient care.

Everolimus and zoledronic acid in patients with renal cell carcinoma with bone metastases: a randomized first-line phase II trial.

BACKGROUND: Bone metastases from renal cell carcinoma (RCC) are a major cause of morbidity. Post hoc analysis has suggested that bone turnover markers can identify patients at risk of skeletal-related events (SREs) among those receiving zoledronic acid. This study sought to evaluate the effect on bone metastases of everolimus alone compared with everolimus plus zoledronic acid. PATIENTS AND METHODS: Thirty treatment-naive patients with RCC and ≥ 1 bone metastases were randomized 1:1 to everolimus (10 mg daily) versus everolimus plus zoledronic acid (4 mg intravenously 4-weekly). Bone-specific assessments were performed at baseline and at weeks 1, 4, 8, and 12. Treatment was continued on allocated arm until progression per RECIST 1.1 (Response Evaluation Criteria in Solid Tumors, version 1.1). The primary outcome measure was urine N-telopeptide (uNTX) level, with secondary measures of plasma C-telopeptide (CTX), quality of life (Functional Assessment of Cancer Therapy-Bone Pain [FACT-BP], Brief Pain Inventory [BPI]), progression-free survival (PFS), SREs, and safety. RESULTS: After 12 weeks, reduction in mean uNTX and CTX on everolimus plus zoledronic acid relative to everolimus was 68.4% (95% CI, 60.1%-74.9%; P < .0001) and 76.2% (95% CI, 67.3%-82.7%; P < .0001), respectively. There was no evidence of a difference for FACT-BP (P = .5), but evidence was favorable for BPI Severity (P = .05) and BPI Interference (P = .06). Median PFS was 7.5 months (95% CI, 3.4-11.2) on everolimus plus zoledronic acid and 5.4 months (95% CI, 3.2-6.3) on everolimus (P = .009). Median time to first SRE was 9.6 months (95% CI, 4.3-15.5) on everolimus plus zoledronic acid and 5.2 months (95% CI, 1.6-8.2) on everolimus (P = .03). CONCLUSION: In this RCC population, the addition of zoledronic acid to everolimus significantly reduced bone resorption markers and may prolong tumor control.

Dose-intense capecitabine, oxaliplatin and bevacizumab as first line treatment for metastatic, unresectable colorectal cancer: a multi-centre phase II study.

BACKGROUND: Dose intense chemotherapy may improve efficacy with acceptable toxicity. A phase II study was conducted to determine the feasibility of a dose-intense two weekly schedule of capecitabine, oxaliplatin, and bevacizumab in metastatic colorectal cancer (mCRC). METHODS: 49 patients with previously untreated mCRC were recruited. Nineteen received capecitabine (1750 mg/m(2) oral BD days 1-7)oxaliplatin (85 mg/m(2)i.v. day 1) and bevacizumab (5 mg/kg i.v. day 1) using a 14-day cycle (C1750). Following toxicity concerns capecitabine was reduced to 1500 mg/m2oral BD (C1500) and 30 further patients recruited. RESULTS: Over 80% of patients received at least 75% of planned chemotherapy doses over the first two cycles. At C1750 Grade 3 or higher toxicity occurred in 74% (95% CI 49% to 91%) and on C1500 in 70% (95% CI 51% to 85%). The median progression-free survival was 6.9 months (95% CI 4.7 to 8.7) for C1750 dose and 8.9 months (95% CI 4.1 to 12.4) for C1500. 3 treatment-related deaths occurred. CONCLUSIONS: Dose intense capecitabine and oxaliplatin with bevacizumab does not show additional efficacy and has potentially significant toxicity. Its use outside of clinical trials is not recommended. TRIAL REGISTRATION: ISRCTN41540878.

Histamine type 2 receptor antagonists as adjuvant treatment for resected colorectal cancer.

BACKGROUND: Anecdotal reports of tumour regression with histamine type 2 receptor antagonists (H(2)RAs) have lead to a series of trials with this class of drug as adjuvant therapy to try and improve outcomes in patients with resected colorectal cancers. There was a plausible scientific rationale suggesting merit in this strategy. This included improved immune surveillance (by way of increasing tumour infiltrating lymphocytes), inhibiting the direct proliferative effect of histamine as a growth factor for colorectal cancer and, in the case of cimetidine, inhibiting endothelial expression of E-selectin (a cell adhesion molecule thought to be critical for metastatic spread). OBJECTIVES: To determine if H(2)RAs improve overall survival when used as pre- and/or postoperative therapy in colorectal cancer patients who have had surgical resection with curative intent. We also stratified the results to see if there was an improvement in overall survival in terms of the specific H(2)RA used. SEARCH METHODS: Randomised controlled trials were identified using a sensitive search strategy in the following databases: MEDLINE (1964 to present), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2009), EMBASE (1980 to present) and Cancerlit (1983 to present). SELECTION CRITERIA: Criteria for study selection included: patients with colorectal cancer surgically resected with curative intent; H(2)RAs used i) at any dose, ii) for any length of time, iii) with any other treatment modality and iv) in the pre-, peri- or post-operative period. The results were stratified for the H(2)RA used. DATA COLLECTION AND ANALYSIS: The literature search retrieved 142 articles. There were six studies included in the final analysis, published from 1995 to 2007, including a total of 1229 patients. All patients were analysed by intention to treat according to their initial allocation. Log hazard ratios and standard errors of treatment effects (on overall survival) were calculated using the Cochrane statistical package RevMan Version 5. Hazard ratios and standard errors were recorded from trial publications or, if not provided, were estimated from published actuarial survival curves using a spreadsheet designed for this purpose (http://www.biomedcentral.com/content/supplementary/1745-6215-8-16-S1.xls). MAIN RESULTS: Of the six identified trials, five used cimetidine as the experimental H(2)RA, whereas one used ranitidine. There was a trend towards improved survival when H(2)RAs were utilised as adjuvant therapy in patients having curative-intent surgery for colorectal cancer (HR 0.70; 95% CI 0.48-1.03, P = 0.07). Analysis of the five cimetidine trials (n = 421) revealed a statistically significant improvement in overall survival (HR 0.53; 95% CI 0.32 to 0.87). AUTHORS' CONCLUSIONS: Of the H(2)RAs evaluated cimetidine appears to confer a survival benefit when given as an adjunct to curative surgical resection of colorectal cancers. The trial designs were heterogeneous and adjuvant therapy has evolved since these trials were performed. Further prospective randomised studies are warranted.