This is of major importance, both for future patients who might need a drug and for the entire population, who pay for the use and sometimes also for the development of drugs. Spending money on worthless or even harmful drugs is depriving patients of other care. Our resources are definitely limited. Although more research is needed on this subject, it seems to me that legal liability is not the central issue. Solving legal liability is clearly not sufficient to create an ethically sound system.
Tort law aims at compensating people for damage resulting from a breach of a duty of care.
It also does more than that. By creating a system of financial liability, people are also urged to act carefully toward others. The duty to inform patients of potential harms further obliges physicians and pharmaceutical companies to respect people's self-determination. Under the proposed policy, the duty of physicians to inform patients should resemble the researchers' duty toward research subjects. Warning them that the drugs are not approved, explicitly mentioning that HPB cannot guarantee the efficacy and safety of the experimental drug, mentioning all the potential risks, and so on, might be sufficient to prevent serious liability claims.