Page 5 of 9 NNT 12 - - - 8-9 12 Outcomes PFS 1st line 2nd line OS 1st line 2nd line ORR 1st-line 2nd-line 2,695 (3) 1,146 (2) 2,695 (3) 684 (1) 2,695 (3) 1,146 (2) 0.68 (0.56, 0.81) 0.86 (0.69, 1.07) 0.95 (0.85, 1.05) 0.90 (0.71, 1.14) 1.46 (1.21, 1.77) 1.58 (1.00, 2.52) p-value 0.0001 0.19 0.338 0.38 < 0.0001 0.05 0.0001 0.14 0.64 1.00 0.008 0.092 8.4 - - - 11.5 8.4 Cuppone et al. Journal of Experimental & Clinical Cancer Research 2011, 30:54 http://www.jeccr.com/content/30/1/54 Table 2 Combined efficacy and activity results Pts (RCTs) HR/RR (95% CI) Het. (p) AD (%) Pts: patients; RCTs: randomized clinical trials; HR: hazard ratio; RR: relative risk; CI: confidence intervals; Het.: heterogeneity; p: p-value; AD: absolute difference; NNT: number needed to treat. Bevacizumab regardless of the treatment lines (interac- tion test p = 0.69) (Table 2). Overall response were sig- nificantly higher in the Bevacizumab arm, regardless of treatment lines (interaction test p = 0.48), with an abso- lute difference of 11.5% and 8.4% for first and second line, respectively, corresponding to 8-9 and 12 patients to be treated for one to benefit (Table 2). Significant adverse events for patients receiving Bevacizumab are listed in table 3. The highest significant difference against the administration of Bevacizumab was HTN, corresponding to 22 patients to be treated for one experiencing the adverse events, although with signifi- cant heterogeneity (p = 0.0001). According to the per- formed meta-regression analysis, more than 3 involved sites, absence of adjuvant chemotherapy, negative hor- monal receptor status and prior administration of anthracyclines are significant predictors of PFS benefit (Table 4). As shown in single trials as well [14,15], prior exposure to taxanes did not compromise the efficacy of Bevacizumab. Discussion The addition of Bevacizumab to chemotherapy is con- sidered one of the most viable treatment options in patients with HER-2 negative metastatic breast cancer, as distinct randomized studies so far presented and pub- lished consistently showed that this association resulted in significantly improved overall response rate and PFS. Notably, the therapeutic benefit was observed in all Table 3 Significant Toxicities results subgroup examined. Nevertheless, the issue of adding Bevacizumab to 1st line chemotherapy for advanced breast cancer is still open, given the recent concerns pointed out by the US Food and Drug administration (FDA), with specific regards to the lack of significant benefit in OS, and the toxicity profile. Moreover, the regulatory panel withheld the indication for breast can- cer, and the final decision is still pending. The main question raised up by the regulatory committee refers to the eventual amount of benefit related to the addition of Bevacizumab. For this reason, a cumulative analysis spe- cifically designed to weight that became mandatory. The data presented herein show a statistically signifi- cant advantage in terms of either progression-free and responses, with an overall absolute benefit of 8% (Table 2). The relative risk reduction in favor of the addition of 1st line Bevacizumab is 32%, and 12 patients are needed to treat in order to see one patient who significantly benefit. This amount of benefit well compares with the benefits of other important therapeutic choices such as the addition of taxanes for the 1st line treatment of metastatic breast cancer, where the advantage in terms of relative risk is about 10%. From a global perspective, the hazard ratios for PFS obtained in the current analysis compare well with those obtained in other studies that have investigated the addition of another drug in the taxane-based che- motherapy. In the study of Albain et al [28], the addi- tion of gemcitabine to paclitaxel for advanced breast Toxicity Hypertension Proteinuria Neurotoxicity Febrile Neutropenia Bleeding Pts (RCTs) 3,841 (5) 3,841 (5) 3,379 (4) 3,379 (4) 3,841 (5) RR (95% CI) 5.15 (1.60, 16.6) 9.55 (3.44, 26.5) 1.20 (1.01, 1.43) 1.39 (1.07, 1.83) 3.05 (1.13, 8.23) p-value 0.006 < 0.0001 0.044 0.015 0.028 Het. (p) < 0.0001 0.96 0.61 0.60 0.56 AD (%) 4.5 0.4 2.6 2.1 0.6 NNH 22 250 39 46 175 Pts: patients; RCTs: randomized clinical trials; HR: hazard ratio; CI: confidence intervals; Het.: heterogeneity; p: p-value; AD: absolute difference; NNH: number needed to harm.