I can apply for a patent for a gadget that I envision. That doesn't mean the gadget does what I purport that it does.
I believe that I can create an engine that uses water as intake, separates the oxygen into hydrogen and oxygen, and then burns the hydrogen and oxygen as fuel. I can also claim that this engine will have zero emissions, and be extremely cheap.
I then submit a patent for this engine, to protect my idea.
Then, I gather venture capital to actually produce the engine.
I produce the engine. It doesn't work.
Since the engine no longer works, I let the patent lapse by not paying the fees. The patent record still exists.
In this case
Check the details for this patent on Google Patents. You can see that the patent lapsed due to non-payment 13 years later. Now, this does not mean that it was lapsed due to the patent not functioning.
To add more, if this drug actually worked, and it was a conspiracy (big pharma blocking the drug) - wouldn't it make more sense to keep the patent alive, so they could kill any company who wanted to sell it?
It is impossible to know just from a patent application if the patent actually functions as claimed. You would need to find a scientific study to prove or disprove this claim.