What are the issues that could arise when a research protocol is approved by an IRB, but the investigator finds out afterwards that a subject is not complying with the protocol requirement, the investigational agent has unexpected toxicities, or the proposed treatment regimen is not effective?
a) The investigator should immediately document the non-compliance and discuss the situation with the subject to address the issue.

b) The investigator should report the unexpected toxicities to the IRB and the sponsor, and revise the protocol if necessary to ensure subject safety.

c) The investigator should closely monitor the treatment regimen and consider alternative options if it is found to be ineffective.

d) The investigator should communicate any issues with the protocol to the IRB and work with them to make any necessary adjustments to ensure the safety and well-being of the subjects.