Why wouldn’t it lead to a reduction in price? Removing artificial barriers to competition lowers prices, that’s like the whole idea behind supply/demand in economics.
The bill is about about "negotiating prices", i.e. price controls. But if you legislate lower prices by fiat and the result is fewer drugs, that's less competition -- which can raise prices.
If there are two drugs available for a condition then not covering one because it's too expensive is more viable. Take one of those companies out of the market and what does that do to your leverage when you're "negotiating" with the other one?