***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: Five trials with 1838 randomised patients were included. There is some evidence for improved overall survival after treatment with purine antagonists compared to alkylators, but statistical significance was not reached (HR 0.89 [95% CI 0.78 to 1.01], 4 trials, N = 1638). However, the relative risk for achieving an overall response (RR 1.22 [95% CI 1.13 to 1.31], 5 trials, N = 1751) and complete remission (RR 1.94 [95% CI 1.65 to 2.28], 5 trials, N = 1751) was significantly higher, resulting in a longer progression-free survival (HR 0.70 [95% CI 0.61 to 0.82], 4 trials, N = 1638). Incidence of grade III/IV infections was significantly higher in patients receiving treatment with purine antagonists (RR 1.83 [95% 1.30 to 2.58], 4 trials, N = 1620). There was no significant difference concerning the relative risk for grade III/IV neutropenia (RR 1.14 [95% CI 0.98-1.34], 4 trials, N = 1620) and therapy-related mortality (RR 0.94 [95% CI 0.45 to 1.95]). Overall incidence of haemolytic anaemia was low, but significantly increased in the purine antagonist group (RR 3.36 [95% CI 1.27 to 8.91], 3 trials, N = 1258). Despite significantly increased overall response and complete remission rates and longer progression-free survival with first-line treatment of B-CLL patients with single-agent purine antagonists, we were not able to detect a statistically significant improvement of overall survival compared to alkylator-based regimens. Furthermore, the use of purine antagonists also augments the risk for grade III/IV infections and haemolytic anaemia.
Output:

This review confirms the greater response rates achievable by using purine antagonists but at the cost of greater toxicity, mainly infections. There is inconclusive evidence whether treatment with purine antagonists improves survival. None of the studies included quality of life data. More research is needed to fully explore the role of purine antagonists in the treatment of B-CLL and their potential impact on survival.