***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Summary The efficacy and toxicity of navelbine 30 mg/m2 administered intravenously ( IV ) over 30 minutes every 3 weeks , and mitomycin C 15 mg/m2 administered IV every 6 weeks was assessed in 34 patients with metastatic breast cancer refractory to first-line chemotherapy . An overall objective response rate of 35 % was achieved ( 95 % confidence interval , 20 % to 53 % ) , with an additional 47 % of patients maintaining stable disease ( SD ) . Four of 12 patients who responded had received previous anthracycline therapy . Median time to progression for responders and patients with SD was 6.3 months . The median survival of all patients was 8.8 months . Tolerance of this regimen was remarkable . WHO grade 3/4 side effects consisted of granulocytopenia in 12 % and thrombocytopenia in 15 % , and included only 1 patient each with grade 3 neurotoxicity and local toxicity due to extravasation . Delay of treatment was required for hematologic toxicity in 7 patients , and 5 required dose reductions . In conclusion , navelbine/mitomycin C is an active and well-tolerated regimen that may be considered for second-line treatment . If our results are confirmed by larger analyses of other patient studies , this combination might also warrant further exploration in combination with other active agents for front line chemotherapy of advanced breast cancer At present , there is no satisfactory treatment for advanced breast cancer patients who have become refractory to anthracyclines . Vinca alkaloids and mitomycin C ( MMC ) are among the drugs most frequently used in this setting . Recently , vinorelbine ( VNR ) has been reported to be highly active in advanced breast cancer . Sixty advanced breast cancer patients previously treated with anthracyclines have been exposed to VNR 25 mg/m2 i.v . on days 1 and 8 , and MMC 10 mg/m2 i.v . on day 1 , with cycles repeated every 4 weeks . There were 3 complete and 21 partial responses for an overall response rate of 40 % ( CI 95 % : 28 - 52 % ) . Median duration of response and median survival were 7 and 10 months , respectively . Myelosuppression was the dose-limiting toxicity , but it was generally mild to moderate . Although this combination appears to be effective and well tolerated , every effort should be made to further improve treatment results in anthracycline-pretreated advanced breast cancer 
    Output:
    
These are associated with a statistically significant difference in survival from the date of progression with the median overall survival ( OS ) being 5 months for primary and secondary resistance , 9 months for progressive disease ( PD ) within 6 months after the last dose of anthracycline and 11 months for PD between 6 and 12 months after the last dose of anthracycline , clearly signaling the need for clarity of definitions in clinical trials of this nature .