There are some different suggestions on what should be done, including ethics review boards and independent verification of results. The UK's investigation of fraud led to this result:
In the same way that there is an external regulator overseeing health and safety, we consider that there should be an external regulator overseeing research integrity," says the committee's report. "We recommend that the government set out proposals on the scope and powers of such a regulator and consult with the research community and other relevant parties to develop them.I understand what they are going for here. They want to prevent another vaccine debacle or prevent another cold fusion lie. I think they also plan to prevent another "Climate gate." While these are noble causes, I can't help but fear that politics will get involved in this process. If a scientist is found of committing true fraud their career is over. There just isn't the right incentives to commit fraud in MOST sciences. Yes, it happens, but it's more likely to be a mistake than true fraud. Which is something that peer review might catch. However, even this is difficult without the initial data set, or recordings of how the experiment was carried out. Scientists are pretty brutal when going through the peer review process. They question everything and you have to have a satisfactory answer to all their questions if you want the results to be published. The true best way to improve scientific debate is to provide incentives to publish articles that have debunked previous research. This will fix more problems than a regulatory board for most of the sciences.
However, then we come to medical sciences. Here there are much greater incentives to commit fraud or intentionally mislead. Why? Well, for a blockbuster drug they can sell Billions in revenue a year. If a drug company thinks that they have a blockbuster on their hands they will try to get it to market sooner. In most cases they have patent protection for at most 10 to 15 years. But you've said patents are for 20 years. That's true, however, it typically takes drug companies 10 years to get a drug to market. After the last ten years they are able to request a 5 year extension.
Why is the system set up like this? Well, the drug companies test a lot of different drugs and not all of them can be blockbuster drugs. A lot of them don't make it through the rigorous testing process either. The drug companies have to pay for all of that as well as make a profit. So, they charge a lot for these blockbuster drugs. They actually do have some different prices to try to help the poor out as well though.
So, in clinical trails there is more incentive to commit fraud or with hold important results. What can be done about it? Well Bernie Sanders (US Senator) has proposed a prize competition for developing different kinds of drugs, which as a stipulation of getting the prize the US government would own the patent. The government would license the patent out so drugs could be cheaper. However, this prize would have to be huge which would again provide more incentives to defraud the government. It would have to be in the billions to allow for the drug companies to recoup their expenses. It could force much stronger restrictions and oversight on the drug trials though. Which could reduce the ability to commit fraud. The prize committee could potentially be made up of scientists that are part of the NIH (National Institute of Health) which would do the data analysis for each of the "Blockbuster" trials thus forcing impartiality into clinical trials.
This could work. Additionally there could be sanctions put on the fraudulent authors, where they are unable to publish for a year, at any level. Where they lose their grants, or are unable to hire new graduate students until they show they have been reformed. This would certainly kill their career. However, this should happen.
Finally, I think that scientists should be required to add any conflicts of interest in the publications as well as sources of funding. In many cases this already happens as the funding agencies require it, however making it an explicit part of the publication process will make it more transparent. Transparency is vital to science.
Science isn't perfect, but it's our best tool for understanding the world around it. Committing fraud on the scientific community and the world as a whole is a horrible crime and should be treated as such.