Alpha-interferon does not increase the efficacy of 5-fluorouracil in advanced colorectal cancer

Improved Antitumor Activity of the Fluoropyrimidine Polymer CF10 in Preclinical Colorectal Cancer Models through Distinct Mechanistic and Pharmacologic Properties

Chemotherapy regimens that include 5-fluorouracil (5-FU) are central to colorectal cancer treatment; however, risk/benefit concerns limit 5-FU's use, necessitating development of improved fluoropyrimidine (FP) drugs. In our study, we evaluated a second-generation nanoscale FP polymer, CF10, for improved antitumor activity. CF10 was more potent than the prototype FP polymer F10 and much more potent than 5-FU in multiple colorectal cancer cell lines including HCT-116, LS174T, SW480, and T84D. CF10 displayed improved stability to exonuclease degradation relative to F10 and reduced susceptibility to thymidine antagonism due to extension of the polymer with arabinosyl cytidine. In colorectal cancer cells, CF10 strongly inhibited thymidylate synthase (TS), induced Top1 cleavage complex formation and caused replication stress, while similar concentrations of 5-FU were ineffective. CF10 was well tolerated in vivo and invoked a reduced inflammatory response relative to 5-FU. Blood chemistry parameters in CF10-treated mice were within normal limits. In vivo, CF10 displayed antitumor activity in several colorectal cancer flank tumor models including HCT-116, HT-29, and CT-26. CF10's antitumor activity was associated with increased plasma levels of FP deoxynucleotide metabolites relative to 5-FU. CF10 significantly reduced tumor growth and improved survival (84.5 days vs. 32 days; P < 0.0001) relative to 5-FU in an orthotopic HCT-116-luc colorectal cancer model that spontaneously metastasized to liver. Improved survival in the orthotopic model correlated with localization of a fluorescent CF10 conjugate to tumor. Together, our preclinical data support an early-phase clinical trial of CF10 for treatment of colorectal cancer.

Fluoropyrimidine Modulation of the Anti-Tumor Immune Response-Prospects for Improved Colorectal Cancer Treatment

Chemotherapy modulates the anti-tumor immune response and outcomes depend on the balance of favorable and unfavorable effects of drugs on anti-tumor immunity. 5-Florouracil (5-FU) is widely used in adjuvant chemotherapy regimens to treat colorectal cancer (CRC) and provides a survival benefit. However, survival remains poor for CRC patients with advanced and metastatic disease and immune checkpoint blockade therapy benefits only a sub-set of CRC patients. Here we discuss the effects of 5-FU-based chemotherapy regimens to the anti-tumor immune response. We consider how different aspects of 5-FU's multi-factorial mechanism differentially affect malignant and immune cell populations. We summarize recent studies with polymeric fluoropyrimidines (e.g., F10, CF10) that enhance DNA-directed effects and discuss how such approaches may be used to enhance the anti-tumor immune response and improve outcomes.

Clinical Efficacy of a Novel Therapeutic Principle, Anakoinosis

Classic tumor therapy, consisting of cytotoxic agents and/or targeted therapy, has not overcome therapeutic limitations like poor risk genetic parameters, genetic heterogeneity at different metastatic sites or the problem of undruggable targets. Here we summarize data and trials principally following a completely different treatment concept tackling systems biologic processes: the principle of communicative reprogramming of tumor tissues, i.e., anakoinosis (ancient greek for communication), aims at establishing novel communicative behavior of tumor tissue, the hosting organ and organism via re-modeling gene expression, thus recovering differentiation, and apoptosis competence leading to cancer control - in contrast to an immediate, "poisoning" with maximal tolerable doses of targeted or cytotoxic therapies. Therefore, we introduce the term "Master modulators" for drugs or drug combinations promoting evolutionary processes or regulating homeostatic pathways. These "master modulators" comprise a broad diversity of drugs, characterized by the capacity for reprogramming tumor tissues, i.e., transcriptional modulators, metronomic low-dose chemotherapy, epigenetically modifying agents, protein binding pro-anakoinotic drugs, such as COX-2 inhibitors, IMiDs etc., or for example differentiation inducing therapies. Data on 97 anakoinosis inducing schedules indicate a favorable toxicity profile: The combined administration of master modulators, frequently (with poor or no monoactivity) may even induce continuous complete remission in refractory metastatic neoplasia, irrespectively of the tumor type. That means recessive components of the tumor, successively developing during tumor ontogenesis, are accessible by regulatory active drug combinations in a therapeutically meaningful way. Drug selection is now dependent on situative systems characteristics, to less extent histology dependent. To sum up, anakoinosis represents a new substantive therapy principle besides novel targeted therapies.

Long-term survival benefits of adjuvant chemotherapy by decreasing incidence of tumor recurrence without delaying relapse in stage III colorectal cancer

BACKGROUNDS AND AIMS

To elucidate the survival benefits of adjuvant chemotherapy by decreasing incidence or by delaying time of tumor recurrence, we reported the long-term results of a nonrandomized prospective study comparing the adjuvant chemotherapy to no chemotherapy in stage III colorectal cancer.

PATIENTS

From 1991 to 1995, 463 patients with stage III colorectal cancer were divided to three groups which were no chemotherapy, weekly chemotherapy, and monthly chemotherapy (5-FU plus levamisole).

RESULTS

The recurrent incidence was significantly decreased in patients with chemotherapy (47.8% vs. 63.9% of no chemotherapy, P = 0.001), resulting into better survival. The 10-year cancer-specific and overall survival rates of patients with chemotherapy vs. no chemotherapy were 52.1% vs. 37.8% and 46.9% vs. 29.9%, respectively (P < 0.001). Weekly chemotherapy had better survival than monthly chemotherapy (P < 0.05). There was no significant difference in recurrent time or types between the patients with and without chemotherapy. The percentages of patients with recurrence happened within 3 years were 85.2% and 84.6% of those with and without chemotherapy, respectively. Patients with advanced stage of T4b invasion depth, N2, and central node invasion had no significant survival benefits by adjuvant chemotherapy.

CONCLUSIONS

Long-term survival benefits achieved by adjuvant chemotherapy is through decreasing recurrent incidence, not through postponing tumor recurrent time. That means adjuvant chemotherapy indeed cures some patients by eradicating occult tumor. In adjuvant setting, more powerful regimen for eradicating occult tumor is the keystone to improve long-term survival of stage III colorectal cancer.

Cancer immunotherapy

Cancer immunotherapy consists of approaches that modify the host immune system, and/or the utilization of components of the immune system, as cancer treatment. During the past 25 years, 17 immunologic products have received regulatory approval based on anticancer activity as single agents and/or in combination with chemotherapy. These include the nonspecific immune stimulants BCG and levamisole; the cytokines interferon-α and interleukin-2; the monoclonal antibodies rituximab, ofatumumab, alemtuzumab, trastuzumab, bevacizumab, cetuximab, and panitumumab; the radiolabeled antibodies Y-90 ibritumomab tiuxetan and I-131 tositumomab; the immunotoxins denileukin diftitox and gemtuzumab ozogamicin; nonmyeloablative allogeneic transplants with donor lymphocyte infusions; and the anti-prostate cancer cell-based therapy sipuleucel-T. All but two of these products are still regularly used to treat various B- and T-cell malignancies, and numerous solid tumors, including breast, lung, colorectal, prostate, melanoma, kidney, glioblastoma, bladder, and head and neck. Positive randomized trials have recently been reported for idiotype vaccines in lymphoma and a peptide vaccine in melanoma. The anti-CTLA-4 monoclonal antibody ipilumumab, which blocks regulatory T-cells, is expected to receive regulatory approval in the near future, based on a randomized trial in melanoma. As the fourth modality of cancer treatment, biotherapy/immunotherapy is an increasingly important component of the anticancer armamentarium.

Contributions of meta-analyses based on individual patient data to therapeutic progress in colorectal cancer

Meta-analysis is the statistical process of combining information from several studies addressing the same question. Meta-analyses based on individual patient data are far more reliable and informative than those based on summary statistics obtained from the trialists or extracted from the published literature. Meta-analysis of randomized clinical trials may contribute to therapeutic progress through (1) establishing efficacy benefits beyond a reasonable doubt, (2) identifying sources of heterogeneity between trials, (3) studying subsets reliably, (4) confirming differences in toxicity profiles, (5) evaluating the cost-effectiveness of experimental therapies, (6) assessing surrogate endpoints, and (7) addressing ancillary questions. All of these potential contributions are illustrated with examples in early and advanced colorectal cancer.

Cetuximab efficacy and safety in a retrospective cohort of elderly patients with heavily pretreated metastatic colorectal cancer

BACKGROUND

Few data are available from clinical trials for elderly patients receiving cetuximab.

PATIENTS AND METHODS

The clinical data of consecutive patients aged > or =70 years given cetuximab for metastatic CRC were retrospectively captured from hospital pharmacy registries in seven centers.

RESULTS

Fifty-six patients received cetuximab+/-with irinotecan. Median age was 76 years (70-84), 86% of patients were pretreated with fluoropyrimidines, irinotecan and oxaliplatin and 69.6% had documented resistance to irinotecan. Objective response rate was 21% (95% CI: 11-32%). The median progression-free survival was 4.4 months (95% CI: 3.0-5.7 months) and the median overall survival was 16.0 months (95% CI: 13.5-18.5 months). Skin rash occurred in 75% of the patients (11% grade 3) and diarrhea in 80% (20% grades 3-4).

CONCLUSION

Tolerability of cetuximab was acceptable in elderly patients with pretreated metastatic CRC. Efficacy appeared similar to that observed in younger patients.

Does a patient’s self-reported health-related quality of life predict survival beyond key biomedical data in advanced colorectal cancer?

The purpose of this study was to determine whether baseline patients' self reported health-related quality of life (HRQOL) parameters could predict survival beyond key biomedical prognostic factors in patients with metastatic colorectal cancer. The analysis was conducted on 299 patients. HRQOL baseline scores were assessed using the European Organisation for Research and Treatment of Cancer, Quality of Life Questionnaire-Core30 (EORTC QLQ-C30). The Cox proportional hazards regression model was used for both univariate and multivariate analyses of survival. In addition, a bootstrap resampling technique was used to assess the stability of the outcomes. The final multivariate Cox regression model retained four variables as independent prognostic factors for survival: white blood cell (WBC) count with a hazard ratio (HR) of 1.961 (95% CI, 1.439-2.672; P<0.001), alkaline phosphatase with HR=1.509 (95% CI, 1.126-2.022; P=0.005), number of sites involved with HR=1.108 (95% CI, 1.024-1.198; P=0.01) and the patient's score on the social functioning scale with HR=0.991 (95% CI, 0.987-0.996; P<0.001) which translates into a 9% decrease in the patient's hazard of death for any 10 point increase. The independent prognostic importance of social functioning and the stability of the final Cox regression model were also confirmed by the additional bootstrap model averaging analysis, based on 1000 bootstrap-generated samples. The results suggest that social functioning, acts as a prognostic measure of survival beyond a number of previously known biomedical parameters.

Meta-analysis of individual patient data from randomized trials: a review of methods used in practice

BACKGROUND

Meta-analyses based on individual patient data (IPD) are regarded as the gold standard for systematic reviews. However, the methods used for analysing and presenting results from IPD meta-analyses have received little discussion.

METHODS

We review 44 IPD meta-analyses published during the years 1999-2001. We summarize whether they obtained all the data they sought, what types of approaches were used in the analysis, including assumptions of common or random effects, and how they examined the effects of covariates.

RESULTS

Twenty-four out of 44 analyses focused on time-to-event outcomes, and most analyses (28) estimated treatment effects within each trial and then combined the results assuming a common treatment effect across trials. Three analyses failed to stratify by trial, analysing the data is if they came from a single mega-trial. Only nine analyses used random effects methods. Covariate-treatment interactions were generally investigated by subgrouping patients. Seven of the meta-analyses included data from less than 80% of the randomized patients sought, but did not address the resulting potential biases.

CONCLUSIONS

Although IPD meta-analyses have many advantages in assessing the effects of health care, there are several aspects that could be further developed to make fuller use of the potential of these time-consuming projects. In particular, IPD could be used to more fully investigate the influence of covariates on heterogeneity of treatment effects, both within and between trials. The impact of heterogeneity, or use of random effects, are seldom discussed. There is thus considerable scope for enhancing the methods of analysis and presentation of IPD meta-analysis.

Monitoring fluoropyrimidine metabolism in solid tumors with in vivo (19)F magnetic resonance spectroscopy

(19)Fluorine magnetic resonance spectroscopy ((19)F MRS) offers unique possibilities for monitoring the pharmacokinetics of fluoropyrimidines in vivo in tumors and normal tissue in a non-invasive way, both in animals and in patients. This method may therefore be useful for predicting response to fluoropyrimidine-based therapy with or without the effects of modulating agents, and this may be of value for the individualization of anticancer therapy and the strategic development of new anticancer drugs. (19)F MRS has been very valuable in elucidating the basic aspects of fluoropyrimidine metabolism, especially in animal studies. Studies in humans have indicated its clinical potential, but widespread application has been hampered by the relatively low detection sensitivity of the method. The recent introduction of clinical MR scanners with magnetic fields above 1.5 T may stimulate increased clinical use of (19)F MRS.

Meta-analysis when only the median survival times are known: a comparison with individual patient data results

BACKGROUND

The hazard ratio (HR) is the most appropriate measure for time to event outcomes such as survival. In systematic reviews, HRs can be calculated either from the raw trial data obtained as part of an individual patient data (IPD) meta-analysis or from the appropriate trial-level summary statistics. However, the information required for the latter are seldom reported in sufficient detail to allow reviewers to calculate HRs. In contrast, the median survival and survival rates at specific time points are frequently presented. We aimed to evaluate retrospectively the performance of meta-analyses using median survival times and survival rates by comparing them with meta-analyses using IPD to calculate HRs.

METHODS

IPD from thirteen published meta-analyses (MAs) in cancers with high mortality rates were used. Median survival and survival rates were calculated from the IPD rather than taken from publications so that the same trials, patients, and extended follow-up are used in each analysis.

RESULTS AND CONCLUSIONS

We show that using median survival times or survival rates at a particular point in time are not reasonable surrogate measures for meta-analyses of survival outcomes and that, wherever possible, HRs should be calculated. Individual trial publications reporting on time to event outcomes, therefore, should provide more detailed statistical information, preferably logHRs and their variances, or their estimators.

Modulation of fluorouracil by leucovorin in patients with advanced colorectal cancer: an updated meta-analysis

PURPOSE

The modulation of fluorouracil (FU) by folinic acid (leucovorin [LV]) has been shown to be effective in terms of tumor response rate in patients with advanced colorectal cancer, but a meta-analysis of nine trials previously published by our group failed to demonstrate a statistically significant survival difference between FU and FU-LV. We present an update of the meta-analysis, with a longer follow-up and the inclusion of 10 newer trials.

PATIENTS AND METHODS

Analyses are based on individual data from 3,300 patients randomized in 19 trials on an intent-to-treat basis. Two trials had multiple comparisons, leading to a total of 21 pair-wise comparisons. FU doses were similar in both arms in 10 pair-wise comparisons, 15% to 33% higher in the FU-alone arm in six comparisons, and more than 66% higher in five comparisons.

RESULTS

Overall analysis showed a two-fold increase in tumor response rates (11% for FU-LV v 21% for FU-LV v 11% for FU [corrected] alone; odds ratio, 0.53; 95% CI, 0.44 to 0.63; P <.0001) and a small but statistically significant overall survival benefit for FU-LV over FU alone (median survival, 11.7 v 10.5 months, respectively; hazards ratio, 0.90; 95% CI, 0.87 to 0.94; P =.004), which were primarily seen in the first year. We observed a significant interaction between treatment benefit and dose of FU, with tumor response and overall survival advantages of FU-LV over FU-alone being restricted to trials in which a similar dose of FU was prescribed in both arms.

CONCLUSION

This updated analysis demonstrates, on a large data set, that FU-LV improves both response rate and overall survival compared with FU alone and that this benefit is consistent across various prognostic factors.

Potential of interferon-alpha in solid tumours: part 2

The second part of this review examines the use of recombinant interferon-alpha (rIFNalpha) in the following solid tumours: superficial bladder cancer, Kaposi's sarcoma, head and neck cancer, gastrointestinal cancers, lung cancer, mesothelioma and ovarian, breast and cervical malignancies. In superficial bladder cancer, intravesical rIFNalpha has a promising role as second-line therapy in patients resistant or intolerant to intravesical bacille Calmette-Guérin (BCG). In HIV-associated Kaposi's sarcoma, rIFNalpha is active as monotherapy and in combination with antiretroviral agents, especially in patients with CD4 counts >200/mm(3), no prior opportunistic infections and nonvisceral disease. rIFNalpha has shown encouraging results when used in combination with retinoids in the chemoprevention of head and neck squamous cell cancers. It is effective in the chemoprevention of hepatocellular cancer in hepatitis C-seropositive patients. In neuroendocrine tumours, including carcinoid tumour, low-dosage (</=3 MU) or intermediate-dosage (5 to 10 MU) rIFNalpha is indicated as second-line treatment, either with octreotide or alone in patients resistant to somatostatin analogues. Intracavitary IFNalpha may be useful in malignant pleural effusions from mesothelioma. Similarly, intraperitoneal IFNalpha may have a role in the treatment of minimal residual disease in ovarian cancer. In breast cancer, the only possible role for IFNalpha appears to be intralesional administration for resistant disease. IFNalpha may have a role as a radiosensitising agent for the treatment of cervical cancer; however, this requires confirmation in randomised trials. On the basis of current evidence, the routine use of rIFNalpha is not recommended in the therapy of head and neck squamous cell cancers, upper gastrointestinal tract, colorectal and lung cancers, or mesothelioma. Pegylated IFNalpha (peginterferon-alpha) is an exciting development that offers theoretical advantages of increased efficacy, reduced toxicity and improved compliance. Further data from randomised studies in solid tumours are needed where rIFNalpha has activity, such as neuroendocrine tumours, minimal residual disease in ovarian cancer, and cervical cancer. A better understanding of the biological mechanisms that determine response to rIFNalpha is needed. Studies of IFNalpha-stimulated gene expression, which are now feasible, should help to identify molecular predictors of response and allow us to target therapy more selectively to patients with solid tumours responsive to IFNalpha.