COX-2 inhibitors and cancer therapeutics: potential roles for inhibitors of COX-2 in combination with cytotoxic therapy: reports from a symposium held in conjunction with the Radiation Therapy Oncology Group June 2001 Meeting

Phase II nonrandomized study of the efficacy and safety of COX-2 inhibitor celecoxib on patients with cancer cachexia

Chronic inflammation is one of the main features of cancer cachexia. Experimental and clinical studies showed that cyclooxygenase-2 inhibitors, such as celecoxib, may be beneficial in counteracting major symptoms of this devastating syndrome. We carried out a prospective phase II clinical trial to test the safety and effectiveness of an intervention with the COX-2 inhibitor celecoxib (300 mg/day for 4 months) on key variables of cachexia (lean body mass, resting energy expenditure, serum levels of proinflammatory cytokines, and fatigue) in patients with advanced cancer at different sites. A sample of 24 patients was enrolled from January to December 2008 and all were deemed assessable. A significant increase of lean body mass and a significant decrease of TNF-alpha were observed. Moreover, an improvement of grip strength, quality of life, performance status, and Glasgow prognostic score was shown. There were no grade 3/4 toxicities. Patient compliance was very good; no patient had to reduce the celecoxib dosage nor interrupt treatment. Our results showed that the COX-2 selective inhibitor celecoxib is an effective single agent for the treatment of cancer cachexia. Although the treatment of cancer cachexia, a multifactorial syndrome, is more likely to yield success with a multitargeted approach; in the present study, we were able to show that a treatment, such as celecoxib, addressing a single target, albeit very important as chronic inflammation, could have positive effects. Therefore, phase III clinical trials are warranted to test the efficacy and safety of celecoxib.

Cyclooxygenase-2 inhibitors and antioxidants in the treatment of cachexia

PURPOSE OF REVIEW

Cancer cachexia is increasingly becoming a critical component in the comprehensive approach to cancer patients influencing morbidity, mortality and quality of life. Therefore its pathophysiology and the main contributing factors have been investigated with the aim of developing effective therapies. Reported findings highlight the role of chronic inflammation and oxidative stress in the onset of cancer cachexia.

RECENT FINDINGS

Chronic inflammation, one of the main features of cancer cachexia, triggers the overproduction of proinflammatory cytokines playing a major role in the pathogenesis of systemic symptoms of cachexia; therefore, antiinflammatory drugs such as cyclooxygenase-2 inhibitors could break the 'vicious circle' leading to the onset and worsening of this devastating syndrome. Likewise, oxidative stress, almost always accompanying cancer cachexia, may be counteracted by effective antioxidant treatments. The most relevant recent clinical approaches addressing these targets are reported.

SUMMARY

Fairly advanced clinical data on efficacy of cyclooxygenase-2 inhibitors and antioxidants in advanced cancer patients are promising, but the best way to administer and combine them with other agents, the optimal dose and timing remain uncertain. However, because cachexia is a multifactorial syndrome, therapeutic approaches targeting a single contributing factor may be inadequate. A rational treatment should thus be multitargeted addressing all key contributing factors.

Molecular markers of radiation-related normal tissue toxicity

Over the past five decades, those interested in markers of radiation effect have focused primarily on tumor response. More recently, however, the view has broadened to include irradiated normal tissues-markers that predict unusual risk of side-effects, prognosticate during the prodromal and therapeutic phases, diagnose a particular toxicity as radiation-related, and, in the case of bioterror, allow for tissue-specific biodosimetry. Currently, there are few clinically useful radiation-related biomarkers. Notably, levels of some hormones such as thyroid-stimulating hormone (TSH) have been used successfully as markers of dysfunction, indicative of the need for replacement therapy, and for prevention of cancers. The most promising macromolecular markers are cytokines: TGFbeta, IL-1, IL-6, and TNFalpha being lead molecules in this class as both markers and targets for therapy. Genomics and proteomics are still in nascent stages and are actively being studied and developed.

Intratumoral COX-2 gene expression is a predictive factor for colorectal cancer response to fluoropyrimidine-based chemotherapy

PURPOSE

Cyclooxygenase-2 (COX-2) is generally elevated in tumors compared with normal tissue and apparently has an important role in tumor development. A number of studies have found high expression of COX-2 to be an unfavorable prognostic factor for overall survival in several cancers. However, the influence of COX-2 expression levels on tumor response to chemotherapy has been relatively little studied. The purpose of this study was to ascertain if COX-2 gene expression is associated with tumor response in the clinical treatment of colorectal cancer with the fluoropyrimidine-based therapy S-1.

EXPERIMENTAL DESIGN

Patients with advanced (stage IV) colorectal cancer were treated with S-1 twice daily based on the patient's body surface area (BSA; BSA < 1.25 m2, 80 mg/d; 1.25 m2 < or = BSA < 1.5 m2, 100 mg/d; BSA > or = 1.5 m2, 120 mg/d) for 28 days followed by a 2-week period rest. mRNA was isolated from paraffin-embedded pretreatment primary tumor specimens and expression levels of COX-2 relative to beta-actin as the internal reference gene were measured using a quantitative reverse transcription-PCR (Taqman) system.

RESULTS

The overall response rate in a group of 44 patients treated with S-1 was 40.9%. Sufficient tumor tissue was available from 40 of these patients for COX-2 mRNA quantitation. COX-2 gene expression was significantly lower in the responding tumors compared with the nonresponders (P = 0.012, Wilcoxon test). Patients with COX-2 values above the cutoff value of 3.28 x 10(-3) had a significantly shorter survival than those with COX-2 gene expressions below the cutoff value (adjusted P = 0.031).

CONCLUSIONS

Intratumoral COX-2 gene expression is associated with likelihood of response to chemotherapy with S-1 and is a prognostic factor for survival of patients after the start of S-1 chemotherapy.

Adverse oral reactions associated with the COX-2 inhibitor rofecoxib

Rofecoxib is an inhibitor of the enzyme cyclo-oxygenase 2 (COX-2) used as an analgesic and anti-inflammatory agent especially in rheumatoid arthritis and osteoarthritis. The adverse effects are generally less than with other anti-inflammatory drugs (NSAIDs), and no oral adverse reactions have been reported in the literature. We present three cases of oral lesions caused by rofecoxib. Extensive erosions appeared, which in all cases resolved on withdrawal of the drug.

Continuous low-dose chemotherapy plus inhibition of cyclooxygenase-2 as an antiangiogenic therapy of glioblastoma multiforme

PURPOSE

Glioblastoma multiforme (GBM) represents the prototype of an angiogenic tumor. Recently, the continuous low-dose scheduling of chemotherapeutic drugs in combination with an inhibition of cyclooxygenase-2 (COX-2) has been suggested as a novel anti-angiogenic approach. The aim of this study was to evaluate the safety and activity of continuous low-dose temozolomide (TMZ) plus the COX-2 inhibitor rofecoxib in patients with newly diagnosed GBM.

METHODS

In vitro, endothelial cells were characterized by a tenfold higher sensitivity to TMZ than glioma cells. Consequently, a subgroup of patients with incompletely resected GBM (n=13) was divided into three groups aiming at a dose escalation to 1/10 of the daily MTD for TMZ: (A) TMZ 10 mg/m2 every third day and rofecoxib 25 mg/d; (B) TMZ 10 mg/m2/d and rofecoxib 25 mg/d; (C) TMZ 5 mg/m2 twice a day and rofecoxib 12.5 mg twice a day. COX-2, VEGF, VEGF Receptor-2, and CD34 were assessed immunohistochemically, in the clinical setting.

RESULTS

The mean follow-up period was 15 months. We observed no severe toxicity attributable to the therapy. Quality of life was not impaired. For the whole study population, median time to progression and overall survival were 8 months and 16 months, respectively. Immunohistochemistry suggested that tumors with higher vessel densities were characterized by a significantly better control than those with lower vessel densities.

CONCLUSIONS

Continuous low-dose TMZ plus rofecoxib is feasible, safe, and maintains good quality of life. This study is indicative of an anti-angiogenic efficacy of continuous low-dose TMZ plus rofecoxib in GBMs, especially in those tumors that are characterized by a high angiogenic activity.