Outcome of advanced NSCLC patients harboring sensitizing EGFR mutations randomized to EGFR tyrosine kinase inhibitors or chemotherapy as first-line treatment: a meta-analysis

BACKGROUND

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) are effective as first-line treatment of advanced non-small-cell lung cancer patients with EGFR mutations (EGFR-M+).

PATIENTS AND METHODS

We conducted a literature-based meta-analysis to quantify the magnitude of benefit with upfront EGFR TKI in EGFR-M+ patients. Meta-regression and sensitivity analyses were also carried out to identify additional predictors of outcome and to assess the influence of trial design.

RESULTS

Five trials (805 patients) were identified (three trials prospectively enrolling EGFR-M+ patients and two retrospective analyses of EGFR-M+ patients). TKI significantly increased progression-free survival (PFS) [hazard ratio (HR) 0.45, 95% confidence interval (CI) 0.36-0.58, P < 0.0001] and overall response rate (ORR) (HR 2.08, 95% CI 1.75-2.46, P < 0.0001)] over chemotherapy, while significantly decreasing neutropenia. No significant difference was observed in overall survival. The rate of exon-19 mutations, female gender, and nonsmoking status were identified as additional predictors of outcome at meta-regression analysis. A significant interaction with trial design was found for both PFS (P = 0.028) and ORR (P = 0.008), suggesting a larger advantage for patients treated within prospective trials.

CONCLUSIONS

In EGFR-M+ patients, first-line TKI increase both PFS and ORR by ~25%, while significantly decreasing toxicity. The role of additional predictive factors and the influence of trial design on the magnitude of the observed benefit warrant further investigation.

Short-term (ST) versus long-term (LT) hormone treatment (HT) in combination with radiotherapy (RT) for locally advanced prostate cancer (LAPC): Meta-analysis of randomized trials (RCTs)

5128

Background: Hormone suppression plus RT is able to significantly decrease the recurrences and the mortality of patients (pts) affected by LAPC. In order to determine if difference exists between ST-HT (HT ≤6 months), and LT-HT (HT ≥8 months) in combination with RT for LAPC, a literature-based meta-analysis was conducted. Methods: Event-based relative risks (RR) with 95% confidence intervals (CI) were derived through a random-effect model. Differences in primary (biochemical failure, BF, and cancer-specific survival, CSS), and secondary outcomes (overall survival, OS, and pattern of recurrence, local or distant, LR/DM) were explored. Absolute differences (AD) and the number of patients needed to treat (NNT) were calculated. Heterogeneity test, a meta-regression analysis with clinico-pathological predictors for outcomes and a correlation analysis for surrogate end-points were conducted as well. Results: Four trials (3,148 patients) were gathered. Data were available for all RCTs only for BF; patient population ranged from 297 to 1,521 pts. Three predictors were identified: median PSA (range 9.5–20.35), Gleason score 7–10 (27–55% pts/trial) and T3–4 (13–77% pts/trial). None of the selected predictors did significantly affect any outcomes. A significant correlation and trend between the log of the BF-RR and DM and OS were found (p=0.029 and p=0.07, respectively). Conclusions: Although with significant heterogeneity (reflecting different patient’ risk stratifications), LT-HT seems to significantly decrease biochemical, local and distant recurrences, and increase cancer specific survival in comparison with ST-HT. Balancing these advantages with toxicities and costs represents the next step of the current analysis.

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No significant financial relationships to disclose.

Magnitude of benefit of the addition of bevacizumab (BEVA) to first-line chemotherapy (CT) for advanced/metastatic colorectal cancer (MCRC): Meta-analysis of randomized clinical trials

e15021

Background: The monoclonal antibody against vascular endothelial growth factor BEVA has recently demonstrated to improve survival for MRC patients (pts). Nevertheless, the magnitude of the provided benefit in the daily practice is still controversial. In order to quantify the benefit of adding BEVA to CT for MCRC, a literature-based meta-analysis was conducted. Methods: Survival Hazard Ratios (HR) were extracted from prospective, randomized clinical trials (RCTs, either phase II/III) reports. HR and event-based relative risks (RR) with 95% confidence intervals (CI) were derived through a random-effect model. Differences in primary (progression-free- and overall-survival, PFS/OS) and secondary outcomes (overall, partial and complete response rates, ORR/PR/CR) were explored. Absolute differences (AD) and the number of patients needed to treat (NNT) were calculated. Heterogeneity test and a meta-regression analysis with clinical predictors for outcomes were conducted as well. A sensitivity analysis according to the trial phase-design was accomplished. Results: Five trials (2,728 pts), 2 phase II (313 pts) and 3 phase III (2,415 pts), were gathered. No significant interaction was found in the sensitivity analysis between phase II and III, although a trend showed a better PFS results for BEVA in phase II trials (p=0.057). At the meta-regression analysis female gender and rectal primary site were significant predictors for PFS (p=0.003, p=0.005). Toxicity analysis is ongoing. Conclusions: Although concerns regarding costs and toxicities still exist, BEVA significantly improves the outcome of untreated MCRC pts. The absolute benefit provided into an unselected population for molecular features should be considered of paramount importance for advanced disease.

[Table: see text]

No significant financial relationships to disclose.

Disease-free survival (DFS) as surrogate end point for overall survival (OS) in adjuvant aromatase inhibitors (AIs) trials for breast cancer (BC): Meta-analysis of 10 randomized clinical trials (RCTs) exploring the magnitude of the benefit

539

Background. The issue regarding the eventual correlation of DFS with OS has not actually been explored in trials addressing the role of AIs. For this purpose, we meta-analyzed all RCTs in which patients were randomized to receive standard tamoxifen or AIs, whatever applied strategies. Methods. A literature-based meta-analysis was accomplished, and event-based relative risk ratios (RRs) with 95% confidence interval (CI) were derived. A fixed- (FEM) and a random-effect (REM) model and heterogeneity test were applied as well. Absolute benefits (AB) and the Number of patients Needed to Treat (NNT) were calculated. A linear regression model considering both each single outcome pair (5-years DFS and OS) has been adopted to explore for correlation, estimated according to Pearson, R2 (parametric) and Spearman (non-parametric) coefficients. Results. Ten RCTs were gathered (27,653 patients); two RCTs did not report the OS result, so they were not evaluable. DFS was significantly improved with AIs, with a AB of 2.3–3.5%, which translate into 29–43 NNT. OS was significantly improved in both overall and early switch strategy, with an AB of 0.8–1.61%, which translate into 120 and 62 NNT, respectively. A strong correlation was found between DFS and OS in the overall (r=0.78, R2=0.60, p=0.001; Rho=0.77, p=0.001) and in the early switch strategy (r=0.83, R2=0.68, p=0.003; Rho=0.84, p=0.002). Although a stronger correlation was found in the upfront strategy, the low number of RCTs did not allow to reaching statistical significance. Conclusions. The strong correlation between DFS and OS in AIs adjuvant endocrine treatment for early BC underlines the choice of DFS as a surrogate end-point for OS. The predictive value of earlier DFS (3-years) estimation for overall survival deserves a further analysis.

[Table: see text]

No significant financial relationships to disclose.

Meta-analysis of adjuvant trastuzumab for early breast cancer: Cardiotoxicity and brain metastases incidence

543

Background: The introduction of adjuvant trastuzumab (T) for early breast cancer overexpressing HER-2 has extraordinarily decreased the risk of both recurrence and death in 5 randomized clinical trials (RCTs). Nevertheless, the issue regarding the long-term safety profile of such drug is still open; in particular, questions remain about long-term cardiotoxicity, and specific pattern of relapse such as brain metastases (BM). In order to quantify the magnitude of these 2 risks, together with the survival outcome, a literature-based meta-analysis was performed. Methods: All phase III trials were considered eligible. A literature-based meta-analysis was accomplished, and event-based relative risk ratios (RR) with 95% confidence interval (CI) were derived. A fixed- and a random-effect model according to the inverse variance and the Mantel-Haenzel method were applied. Heterogeneity test was applied as well. Absolute differences (AD) and the number of patients needed to treat or to harm (NNT/NNH) were calculated. Primary end-points were: 1) chronic heart failure grade III-IV rate (CHF), 2) 10% reduction of L-FEV rate (L-FEV) and 3) BM rate. In order to quantify the magnitude of the significant benefit already found in the original RCTs, secondary end-points were: 1) disease-free survival (DFS) and 2) overall survival (OS). Results: Five RCTs were gathered (11,187 patients); at an average 2-yrs follow-up, all data were available for the cardiotoxicity and outcome end-points, while 3 RCTs reported results for BM analysis (6,738 patients). Conclusions: The overall outcome stresses that trastuzumab is likely to be one of the most important discovery in clinical oncology. Nevertheless, the biological activity of trastuzumab needs to be investigated more extensively to explore both long-term safety and specific relapse pattern.

[Table: see text]

No significant financial relationships to disclose.

Cardiotoxicity of weekly trastuzumab (T) plus epirubicin (E) and paclitaxel (P) for HER2-positive locally advanced (LA) and/or metastatic (M) breast cancer (BC): A feasibility phase II study

11509

Background: The introduction of T for patients (pts) overexpressing HER-2 changed the natural history of BC. The adjunction of T to anthracyclines and taxanes for both LABC and MBC provided a significant incidence of unexpected cardiotoxicity. Given the low cardiac toxicity in our previous experience with weekly ET in unselected MBC pts, a feasibility phase II study aimed to cardiotoxicity was planned. Methods: Pts affected by untreated LABC/MBC overexpressing HER-2 by FISH/CISH amplification or 3-positive Dako- Test, underwent weekly T (4–2 mg/kg/week), day 1, and E (25 mg/m2/week) plus P (80 mg/m2/week), day 2, plus G-CSF support, for 16/24 consecutive weeks in absence of progression or toxicity, in LA/M pts, respectively. Pts with significant cardiac disease/L-FEV<50% were excluded. Primary endpoint was the rate of pts with L-FEV reduction >10% after 12 weeks. An optimal 2-stage Simon design was applied. With a power of 90% at a 5% significance level, assuming a toxicity rate of 30% as unacceptable, and less than 10% as acceptable, an initial group of 15 pts was required; with 11 pts with no toxicity, a second step with further 21 pts (total 36) was planned. Non-cardiac toxicity and activity were evaluated as secondary end-points. Results: From May 2004 to November 2006, 15 pts entered the study. Patient characteristics: median age=47 (range 37–69); LABC/MBC=4/11; positive hormonal receptor 8/7; menopausal pre/post=7/8; PS 0/1=14/1; number of met sites 1/2/3=7/6/2. Median baseline- and post-week-12-L-FEV was 69% (range 64–77) and 65% (range 61–76), respectively. With a median number of courses of 13 (range 8–24), 3 pts had a >10% L-FEV reduction (20%), with an overall median L-FEV reduction of 5.2%. No EKG alteration or specific symptoms were registered. With a 17-months median follow-up, 13 pts were evaluable for response. Eight response (61.5%, 95% CI 9- 87) were documented, with a median response duration of 9 months. No grade 3–4 toxicity were registered, with the exception of severe alopecia. Conclusions: The weekly administration of T plus E and P is extremely tolerable, also with regard to L-FEV reduction. The low L- FEV reduction rate allowed entering the second step of the study.

No significant financial relationships to disclose.

Does progression-free-survival (PFS) correlate with overall- and cancer-specific survival (OS/CSS) in randomized clinical trials (RCTs) exploring the addition of hormonal therapy (HT) to radiotherapy (RT) for early prostate cancer (EPC)? Analysis of six RCTs

5056

Background: Although PFS is considered the standard primary end-point in EPC, the correlation with OS has never been explored in RCTs randomizing patients (pts) to HT plus radiotherapy (RT) versus RT. Given the relatively long prognosis in this disease setting, the correlation between PFS and CSS should be investigated as well. Methods: All phase III trials reporting all outcome’ data were considered eligible. The correlation has been explored according to a linear regression model considering both each single outcome pair (PFS, OS and CSS rates) for all arms, and each reported Hazard Ratio (HRs). The correlation was estimated according to both the Pearson- (r) and R2-coefficient (parametric) and the Spearman coefficient (Rho, non-parametric). A sensitivity analysis in 2 subgroups (long- and short-term HT) to test for effect robustness has been accomplished as well. A model to determine the target sample size to determine CSS benefit of 3%, 4%, 6% and 7% months, respectively, was calculated as well. Results: Six RCTs (4,212 pts) were collected (follow-up range: 4.5–7.6 years). In the overall population, when considering the crude rates, a linear stronger correlation was found between PFS and CSS (r=0.71, R2=0.51, p=0.003; Rho=0.75, p=0.005), rather than with OS (r=0.55, R2=0.30, p=0.06; Rho=0.78, p=0.11). Again, when considering HRs, a linear stronger correlation was found between PFS and CSS (r=0.87, R2=0.76, p=0.02; Rho=0.94, p=0.005), rather than with OS (r=0.75, R2=0.56, p=0.08; Rho=0.77, p=0.07). Similar correlations were found whatever subgroups was explored. The sample size model (on the basis of the beta-coefficient=0.71), calculate 4,575, 2,006, 1,115 and 700 pts to improve PFS of 4%, 6%, 8%, and 10% months, which means to improve CSS of 2.8%, 4.3%, 5.7% and 7.1%, respectively. Conclusions: The correlation between PFS and CSS in RCTs exploring the benefit of adding HT to RT for EPC is significant, and suggests its further investigation as surrogate end-point. The natural history of the disease clearly explains the stronger correlation of PFS with CSS rather than with OS.

No significant financial relationships to disclose.

Three-year disease-free survival (DFS) as surrogate end-point for predicting five-year overall survival (OS) benefit in adjuvant taxane-based chemotherapy for breast cancer (BC): Analysis of 10 randomized clinical trials (RCTs)

584

Background: The issue regarding the eventual correlation between DFS at earlier follow-up (i.e. 3-yrs) with 5-yrs OS has not actually been explored in trials addressing the role of taxanes in BC. All RCTs in which patients were randomized to receive a standard or a taxane-based regimen for early BC were analyzed to evaluate this topic. Methods: All phase III trials with at least 60 month follow-up were considered eligible. The correlation has been explored according to a linear regression model considering both each single outcome pair (DFS/OS) for all arms (extracted by curves), their differences, and each outcome Hazard Ratio (HR) or calculated Relative Risk (RRs), following 2 steps: 1) correlation between 5-yrs DFS and OS (to confirm the evidence); 2) correlation between 3-yrs DFS and 5-yrs OS (predictive role). The correlation was estimated according to Pearson (r) and R2 coefficients (parametric) and Spearman (Rho) coefficient (non- parametric). A model to calculate the target sample size to determine 5-yrs OS benefit of 3%, 5% and 7%, respectively, was calculated as well. Results: Ten RCTs (17,067 patients) with available data for outcomes were gathered. For 5-yrs DFS/OS, a linear correlation was found between rates (r=0.74, R2=0.55; p<0.0001; Rho=0.83; p<0.0001), and HRs (r=0.90, R2=0.81; p<0.0001; Rho=0.91; p<0.0001). Three-yrs DFS correlates with 5-yrs OS, with both rates (r=0.81, R2=0.66; p<0.0001; Rho=0.92; p<0.0001), and RRs (r=0.84, R2=0.71; p=0.002; Rho=0.85; p=0.002). Three-yrs DFS and 5-yrs OS absolute differences strongly correlate (r=0.86, R2=0.74; p=0.001; Rho=0.84; p=0.002). The sample size model (on the basis of the r-coefficient=0.81), calculates 2,733, 863, and 389 pts to improve 3-yrs DFS of 4%, 7% and 10%, which means to improve 5-yrs OS of 3.2%, 5.7% and 8.1%, respectively. Conclusions: By these data, 3-yrs DFS is a reliable surrogate end-point for OS when testing new drugs in early BC, and is able to predict a late survival benefit. Thanks to the smaller patient sample size, RCTs with this design will provide early results in a shorter time period, allowing a faster data transfer to clinical practice.

No significant financial relationships to disclose.

Surrogate endpoints for overall survival (OS) in advanced pancreatic cancer (APC): Analysis of randomized clinical trials (RCTs) exploring gemcitabine (G)-based combinations

4575

Background: G-based combinations often result in an improved overall response rate (ORR) in APC; this improvement in ORR, however, seldom translates into a significant OS advantage. We therefore evaluated the appropriateness of ORR and progression-free survival (PFS) as surrogate endpoints for OS in RCTs comparing single-agent G and G-based combinations as first-line treatment for APC. Methods: Phase III trials reporting ORR or PFS and OS data were considered eligible. Potential correlations were explored according to a linear regression model considering both the actual outcome (ORR or PFS and OS) for each single arm and the calculated relative risk (RR) for each outcome in paired comparisons. Correlation was estimated according to Pearson’s (r) and R2 coefficients (parametric) and Spearman’s (Rho) coefficient (non-parametric). A model to calculate the target sample size to correctly identify 0.4, 0.7, and 1.5 mos benefits in OS was derived as well. Results: Nineteen (6,288 pts) and 17 (4,882 pts) RCTs were identified for the ORR/OS and PFS/OS correlation, respectively. When considering ORR rates and medians, ORR did not significantly correlate with OS (r=0.23, R2=0.06, p=0.14; Rho=0.16, p=0.33), while PFS showed a strong linear correlation (r=0.75, R2=0.56, p<0.0001; Rho=0.90, p<0.0001). Similarly, when considering RRs, ORR did not significantly correlate with OS (r=-0.17, R2=0.03, p=0.46; Rho=-0.18, p=0.44), while PFS showed a strong linear correlation (r=0.91, R2=0.82, p<0.0001; Rho=0.59, p=0.01). Based on these data, we derived a sample size model (beta-coefficient=0.75) to calculate how many patients would be necessary to demonstrate a significant OS advantage of 0.4, 0.7 and 1.5 mos, respectively, using PFS as a surrogate endpoint; according to this model, 0.5, 1, and 2 months improvements in PFS would be necessary to translate into the target OS advantages, requiring 2,370, 678 and 222 pts, respectively. Conclusions: In APC, ORR does not seem to correlate with OS. Conversely, PFS could be a reliable surrogate endpoint for survival in this setting, although the detection of relatively small differences in PFS would require a remarkably large sample size.

No significant financial relationships to disclose.

Adjuvant LH-RH agonists for premenopausal early breast cancer: A meta-analysis of randomized clinical trials (RCTs) exploring the magnitude of the disease-free and overall survival (DFS/OS) benefit

592

Background: LH-RH agonists are considered as a milestone for adjuvant treatment for premenopausal early breast cancer patients (pts). All RCTs in which ovarian ablation (OA) with/without tamoxifen (TAM) and/or chemotherapy (CT) was compared with tamoxifen (TAM) and/or chemotherapy (CT) were pooled to estimate the magnitude of the benefit in both DFS and OS. Methods: A literature-based meta-analysis was accomplished, and event-based relative risk ratios (RRs) with 95% confidence interval (CI) were derived. A fixed- (FEM) and a random-effect (REM) model according to the inverse variance and heterogeneity (Het) test were applied as well. Absolute benefits (AB) and the number of pts needed to treat (NNT) were calculated. A sensitivity analysis to test for effect robustness in 4 sub-populations (OA/OS vs CT; OA/OS + CT vs CT; OA + TAM vs CT; OA + TAM vs observation) was accomplished. Results: Fifteen RCTs were gathered (12,545 pts); one RCT did not report the OS result. Results are depicted in the table . Conclusions: Although differences across RCTs exist in median follow-up time (as demonstrated by heterogeneity), OA seems to significantly improve DFS when combined with CT over CT alone, when combined with TAM versus CT alone and when combined with TAM versus observation. Actually, these DFS benefits do not translate into an OS benefit, with the exception of the last subgroup.

[Table: see text]

No significant financial relationships to disclose.

Ten-year experience with weekly chemotherapy in metastatic breast cancer patients: Multivariate analysis of prognostic factors

10652

Introduction: Weekly administration of chemotherapy represents an emerging option for the treatment optimization of metastatic breast cancer (MBC). Moreover, evidences suggest a intriguing mechanism of action for weekly paclitaxel, which involves pro-apoptotic and anti-angiogenetic pathways. In order to identify clinical and biological prognostic factors for weekly chemotherapy outcome, we performed a multivariate analysis in a 10-years experience of weekly 1st line chemotherapy for MBC patients. Methods: The original databases of phase II trials of MBC patients undergone 1st line weekly chemotherapy were collected. Clinical and biological co-variables were screened for the eventual relationship with time to progression (TTP) and overall survival (OS) into a Cox model. Results: From 1990 to 2003, 184 patients were enrolled in 3 consecutive phase II studies, to evaluate activity and tolerability of weekly epirubicin with lonidamine, or vinorelbine or paclitaxel, for 24 weeks. All patients were evaluable for clinical variables, while histological samples were available in only 40 patients. At a median follow-up of 24 months, median TTP was 9 months (95% CI 8–10) and median OS 34 (95% CI 24–42). Independent variables were: response (HR 2.34, p < 0.0001), receptor status (HR 1.62, p = 0.01) Performance Status (PS) (HR 2.31, p < 0.0001) for TTP, and response (HR 1.86, p = 0.005), PS (HR 2.81, p < 0.0001), dominant metastatic site (HR 2.27, p < 0.0001), enrollment period (HR 2.51, p = 0.001) for OS. Although no biological factors entered the Cox model due to the small sample size, some sub-populations showed negative trend in survival. Conclusions: In our series of patients undergone weekly chemotherapy for MBC, independent prognostic factors for survival improvement were responders, PS 0–1, non-visceral dominant metastatic site, and enrollment period. Further greater populations are needed to extensively screen for biological prognostic factors.

No significant financial relationships to disclose.

Early switch with aromatase inhibitors as adjuvant hormonal therapy for postmenopausal breast cancer: Pooled-analysis of 8,794 patients

635

Background: The magnitude of the survival benefit of aromatase inhibitors (AIs) after 2–3 years of tamoxifen as adjuvant hormonal therapy for early breast cancer is still unclear. We performed a pooled-analysis of phase III trials, to look how much advantages adjuvant the “early switch” strategy add over standard tamoxifen for 5 years. Methods: All phase III trials were considered eligible. A pooled analysis was accomplished, and event-based relative risk ratios (RR) with 95% confidence interval (CI) were derived. Significant differences in primary outcome (EFS and RFS, event- and relapse-free survival), and secondary outcomes (OS, overall survival, deaths in absence of progression, other cancers and toxicities), were explored. Magnitude outcome measures were: absolute benefits (AB) and number of patients needed to treat (NNT). Heterogeneity test was applied as well. Results: Four trials designed to look if AIs after 2–3 yrs of TAM improve EFS (8794 patients) were gathered. Conclusions: Considered all the available phase III trials, the early switch strategy improves survival over standard tamoxifen for 5 years, with a different toxicity profile. The lack of significant heterogeneity in the analysis underscores the homogenous effect across all trials.

[Table: see text]

No significant financial relationships to disclose.