As a new indication for a drug, the cost of clinical trials is actually not very high, especially for oral medications. Additionally, if approved, the FDA grants a 3-year market exclusivity for new indications. I suspect that many doctors are unfamiliar with FDA policies. So, this isn't likely a matter of money, but rather a lack of confidence in the approval of these drugs for new cancer indications through clinical trials.
Probably not enough $ to be made
As a new indication for a drug, the cost of clinical trials is actually not very high, especially for oral medications. Additionally, if approved, the FDA grants a 3-year market exclusivity for new indications. I suspect that many doctors are unfamiliar with FDA policies. So, this isn't likely a matter of money, but rather a lack of confidence in the approval of these drugs for new cancer indications through clinical trials.