Background: The value of drugs will evolve over time as new evidence for risks and benefits emerge and the price of a drug changes. Methods: A NICE Evidence Search on March 1, 2017 revealed 25 systematic reviews and 55 economic evaluations of filgrastim.1 Results: Initial Health Technology Assessments (HTA) suggested low value due to high drug cost and no evidence for significant gain in Overall Survival (OS). More recent metanalyses of placebo-controlled randomized trial data show absolute OS gains of 3.2% (95% CI:2.1—4.2%) from filgrastim support of cytotoxic chemotherapy2 and falling costs due to biosimilar competition. Conclusions: Physicians and payers need to be aware that HTA decisions need constant re-evaluation, especially following the launch of biosimilar alternatives. This explains the first inclusion of filgrastim in the WHO essential Drug List for cancer more than 20 years after its original approval in 1991,3 and demonstrates the power of biosimilar medicines in transforming healthcare.