&gt;It&#x27;s very hard for me to believe combined therapies can beat evolution.<p>Obviously the faster an organism mutates&#x2F;replicates the harder it is to slow&#x2F;stop evolution. HIV for example is &quot;worst case scenario&quot; but with combination therapies we&#x27;ve managed to make HIV a treatable disease.<p>At the end of the day it all boils down to one hard fact. An organism can&#x27;t evolve if it is extinct. Selection works by causing deaths in a population (ex selecting those which live on). If you raise the &quot;cost of selection&quot; so high that an organism can&#x27;t pay the cost in deaths, the population goes extinct.<p>As a rule of thumb, to fix an adaptive change, it takes 20 times the population in deaths. So if the current population is 1000, it&#x27;ll take 20,000 deaths (and by deaths I mean removing an unfit allele from the population) over many generations to fix that adaptive allele.<p>&gt;Of course I don&#x27;t even know what &quot;combined therapies&quot; is, so I&#x27;m probably wrong. What am I missing?<p>Therapies or methods that employ more than one independent mode-of-action. Ex: Two drugs given at the same time.<p>This forces the organism to adapt to two things at once, doubling the cost of selection. As you increase modes of action, the cost rises to the point that it is impossible to adapt before the population goes extinct.