He’s reducing the cost of drugs the same way he is responding to the opioid epidemic: by saying whatever sounds good at the moment and then ignoring the problem.
As with all policy issues that require more than a tweet, Trump will simply follow the lead of the Republicans in Congress.
So the real question is what are congressional Republicans willing to do about drug costs. The answer to that is simple: nothing.
Congress is willing – in fact eager – to hold hearings in which they get free publicity righteously scolding pharma bros. But those hearings are never followed up by legislation. They are purely theater.
There is no incentive for Congress in general and Republicans in particular to act. In both the ACA repeal efforts and the tax bill, we saw that Republicans were more than willing to push forward bills that were extremely unpopular with the electorate as a whole, but which were strongly favored by their donor class.
Pharma companies are very much a part of that donor class, as they proved in the last election. Republicans are not going to cross them. Not now, not ever.
Trump can say whatever he wants. But there will be no drug price control measures enacted under his watch.