Loupakis F, Cremolini C, Salvatore L, Schirripa M, Lonardi S, Vaccaro V, Cuppone F, Giannarelli D, Zagonel V, Cognetti F, Tortora G, Falcone A, Bria E. Clinical impact of anti-epidermal growth factor receptor monoclonal antibodies in first-line treatment of metastatic colorectal cancer: meta-analytical estimation and implications for therapeutic strategies.
Cancer 2011;
118:1523-32. [PMID:
22009364 DOI:
10.1002/cncr.26460]
[Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 06/17/2011] [Accepted: 06/22/2011] [Indexed: 01/15/2023]
Abstract
BACKGROUND
Antiepidermal growth factor receptor (anti-EGFR) monoclonal antibodies (MoAbs) are indicated for the treatment of metastatic colorectal cancer patients, but some scientific issues concerning their efficacy are currently unsolved.
METHODS
A literature-based meta-analysis was conducted. Hazard ratios (HRs) were extracted from randomized trials for progression-free survival (PFS) and overall survival (OS); the event-based risk ratio was derived for response. Sensitivity analyses to look for interactions according to KRAS status and chemotherapy association regimens were performed.
RESULTS
Eight trials (6609 patients) were identified. A significant interaction according to KRAS status was found for PFS (wild type vs mutant, P = .001) and response rate (wild type vs mutant, P < .0001). The addition of an anti-EGFR MoAb to first-line chemotherapy increased PFS in the KRAS wild-type population (HR, 0.91; 95% confidence interval [CI], 0.84-0.99; P = .03), and had a detrimental effect in the KRAS mutant population (HR, 1.13; 95% CI, 1.03-1.25; P = .013). A significant increase in the probability of achieving a response was evident in KRAS wild-type patients (relative risk, 1.17; 95% CI, 1.04-1.33; P = .011). In this population, the interaction in response rate according to adopted chemotherapy favored irinotecan-containing regimens (P = .01), and at meta-regression analysis the relative increase in response rate was significantly related to PFS (P = .00001) and OS (P = .00193) benefit.
CONCLUSIONS
The addition of an anti-EGFR MoAb to first-line chemotherapy produces a clear benefit in response rate. This advantage is restricted to KRAS wild-type patients and translates into a small benefit in PFS. At present, irinotecan-based backbone chemotherapy could be a preferable option. The correlation between activity and survival parameters corroborates the hypothesis that anti-EGFR MoAbs might be more suitable for patients needing tumoral shrinkage.
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