By happy coincidence, I was reading this yesterday - <a href="http:&#x2F;&#x2F;blogs.sciencemag.org&#x2F;pipeline&#x2F;archives&#x2F;2016&#x2F;01&#x2F;26&#x2F;medivation-decides-that-their-drug-isnt-what-they-thought" rel="nofollow">http:&#x2F;&#x2F;blogs.sciencemag.org&#x2F;pipeline&#x2F;archives&#x2F;2016&#x2F;01&#x2F;26&#x2F;med...</a><p>&gt; The FDA does not actually require you to have a mechanism – that’s a common misconception. The FDA wants to see safety and efficacy. Now, a known mechanism will probably make the assessment of both those factors easier, to be sure, so all things being equal, you’d rather know how your drug works.