This is a huge deal with drugs that can cost $10k per vial. The manufacturers have no incentive to test for longer periods: it would just mean less revenue and

This is a huge deal with drugs that can cost $10k per vial. The manufacturers have no incentive to test for longer periods: it would just mean less revenue and more risk. And as I've mentioned before, physicians are very conservative and don't like stepping outside what other people do even if the basic research is there. For example, the ability to pool leftover amounts of Yervoy (ipilimumab) among patients could save thousands of dollars each. The research so far shows that cancer drug Yervoy remains sterile, stable and effective for at least a month [1] but the manufacturer's guidelines say to use immediately after opening and throw away the rest. (Ironically the independent researchers couldn't afford to do a larger study because the vials were so expensive in the first place!) It also limits how the drugs are delivered. For example, IL-2 (as a cancer immunotherapy) might be safer, more effective and more convenient as a single continuous infusion over a few weeks [2]. But the guidelines say to use immediately and throw away the excess. It also limits research into what I think is the most promising near-term approach to cancer: intra-tumoral immunotherapy (with frequent low doses of e.g. ipi, nivo, IL-2 into lesions). Unfortunately this is way too expensive if you have to throw away 99% of a vial for each injection. [1] https://www.ncbi.nlm.nih.gov/m/pubmed/26922168/ https://www.ncbi.nlm.nih.gov/m/pubmed/26922168/ [2] https://www.ncbi.nlm.nih.gov/m/pubmed/10996039/ https://www.ncbi.nlm.nih.gov/m/pubmed/10996039/