... risks in assuming the drug will stay on the market.

If it can be done inexpensively, and with permission of the use of other firm's patents to obtain the sufficient proprietary creative work to obtain their own patent, then yeah sure it can be done. (Most drug companies are using the patents of other firms to conduct their research, hence the remark about other drug companies going belly up.. why would a firm authorize the use of their patent, just to make that patent obsolete.. that's all I'm meant as many patents go obsolete, eventually)...

But there has never been anything even remotely close to "inexpensive" in the arena of cancer research and drug approval, not to mention the ongoing assumed risk of having a drug on the market. So far, it's proven to be outrageously expensive just to get a life extending drug on the market. Just go read about the most recently released metastatic CRC drug, Lonsurf. Released about 3 or 4 years ago. Gives stage 4 patients about 8 months at a cost that exceeds 9 digits. Only a fraction of those patients even qualify for it. It was incredibly risky to even develop something that small.

A drug purported to be a cure might cost as high as a billion to develop. There's practically nobody willing to take on such a risk, regardless of the potentially promising results.

How stupid do I think you are? Has nothing to do with intelligence, just exposure to these industry dynamics. I'm just trying to help folks understand the barriers to entry these drugs face and why these headlines fizzle out.