That may be correct. Other factors besides plasma half life can influence a drugs biologic effect. These include tissue distribution,binding to cellular receptive proteins and intracellular biologic effects. The latter 2 could change the pharmacodynamics from human cancer cells to viruses.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2990149/

https://www.ncbi.nlm.nih.gov/pubmed/28838028