A Comparison of white and African American outcomes from a three-arm, randomized, phase III multicenter trial of advanced or metastatic non-small cell lung cancer

PURPOSE

To investigate the effect of race on the efficacy and safety of standard chemotherapy doublet regimens in African American patients, we conducted a subgroup analysis of a phase III randomized trial.

PATIENTS AND METHODS

Chemonaïve patients with a performance status of 0 or 1 and stage IIIB or IV non-small cell lung cancer were randomized to arm A: gemcitabine 1000 mg/m2 on days 1 and 8 plus carboplatin area under the curve 5.5 on day 1; arm B: the same schedule of gemcitabine plus paclitaxel 200 mg/m2 on day 1; or arm C: paclitaxel 225 mg/m2 on day 1 plus carboplatin area under the curve 6.0 on day 1. Cycles were repeated every 21 days up to 6. A site selection tool identified institutions with potential to recruit a minority population. Outcome and toxicity data of white and African American patients were compared.

RESULTS

Of 1135 total patients, 972 were white (85.6%) and 138 were African American (12.2%). Median survival was 8.3 months for white patients (95% confidence interval [CI]: 7.7-9.3) and 9.1 months for African American patients (95% CI: 8.2-11.1). Response rates were 29.1 and 29.0%, respectively. Rates of grade 3 or 4 toxicities were comparable. Among African Americans, median survival was 7.2 months (95% CI: 5.1-10.1) for gemcitabine-carboplatin (n = 47), 10.5 months (95% CI: 7.1-15.4) for gemcitabine-paclitaxel (n = 42), and 10.2 months (95% CI: 8.5-13.2) for paclitaxel-carboplatin (n = 49).

CONCLUSION

Whites and African Americans had similar outcomes, although there was some variability in survival among African Americans across the three treatment groups.

Inflammation and CYP3A4-mediated drug metabolism in advanced cancer: impact and implications for chemotherapeutic drug dosing

BACKGROUND

The inability to accurately predict treatment outcomes for cancer patients in terms of tumour response and anticancer drug toxicity is a severe limitation inherent in current approaches to chemotherapy. Many anticancer drugs are metabolically cleared by cytochrome P450 3A4 (CYP3A4), the predominant CYP expressed in liver. CYP3A4 expression exhibits marked interindividual variation and is repressed in acute inflammatory states.

OBJECTIVES

(1) To review the relevance of CYP3A4 variability to drug metabolism in the setting of cancer and to understand how inflammation associated with malignancy contributes to both this variability and to adverse treatment outcomes. (2) To examine the relationship between tumour-induced inflammation and repression of CYP3A4 and to explore methods of dosing of anticancer drugs in the setting of advanced cancer.

METHODS

Review of relevant literature covering both human and animal studies as well as in vitro mechanistic studies.

RESULTS/CONCLUSIONS

Interindividual variability in CYP3A4 expression is a major confounding factor for effective cancer treatment and methods to predict CYP3A4-mediated drug clearance may have clinical utility in this setting. Although acute inflammation has long been recognised to repress drug metabolism, it is now becoming apparent that cancer patients exhibiting clinical and laboratory features of an inflammatory response have reduced expression of CYP3A4 and possibly other genes relevant to anticancer drug disposition.