I've got news for you - quite a lot of drugs are trialled on the cheap in 3rd world countries already.
That is often how they decide to run more formal trials in first world countries before giving final registration for use. The process for many big pharma companies is as follows: 1) find a market, 2) identify an illness within that market, 3) develop a drug (if there is one already available then develop a 'me too' isomer - see venlafaxine and desvenlafaxine for an example), 4) trial the drug on animals, 5) trial the drug in a poorly regulated part of the world, 6) trial the drug in the country where the majority of the sales will come from.
There are numerous famous cases of how this has been done (often with horrific results). A notable one being the trial of the antibiotic Trovan in Nigeria by Pfizer which resulted in the deaths of several children (who had not been informed of the risks).
I do agree though that first world governments do need to play a larger role in making sure that adequate advances are made in the treatment of diseases like tuberculosis (as a part of being responsible global citizens). Sadly, drug companies invest the lion's share of their research money into diseases that are largely first world problems (antihypertensives, psychotropics, potassium pump inhibitors etc.). This does leave the diseases of the tropics and the developing world largely neglected in terms of funding for new drugs and results in millions of deaths that could have been averted.
With tuberculosis in particular this has been a real issue in some parts of the world. In Papua New Guinea for example, a reliance on old fashioned long-duration treatments with drugs like isoniazid and rifampicin (which are decades old) has often enabled poor treatment compliance, which in turn has allowed multi-drug resistant strains of Mycobacterium tuberculosis to become a serious issue. What really annoys me on this one, is that it has taken the danger of these resistant strains crossing into Australia via the Torres Strait to get the government off of its ass and into gear on responding.
There are plenty of other diseases that are worthy of more attention also, among them leishmaniasis and schistosomiasis, which are nasty parasitic diseases that cause immeasurable suffering. What is noteworthy here too actually is that diseases like tetanus and whooping cough are still major causes of death in the developing world - these are largely preventable via innexpensive treatment and/or vaccination.
Things won't really change in that industry though until people become more educated and being to give more of a shit about the developing world. Disappointingly, my experience of most people in developed countries (like mine, Australia) is that they would rather bury their heads in the sand than grapple with the painful truth on this issue - especially if it means any money out of their pocket, however little.
I also agree that it can be fairly silly that some countries will not really take on board the very stringent rulings of other countries that particular drugs are safe. Though this argument is a little bit of a double-edged sword, as there have been cases where the FDA has approved a drug and the TGA here in Australia has not due to safety concerns (we seem to be a little less swayed by the drug companies on what does and does not get approved). I think safety based arguments like these are pretty reasonable.
On my knowledge of this area, I have worked in the pharmaceutical industry for a number of years and also studied quite a lot of pharmacology as an undergraduate. These days I work in the genetics of infectious disease resistance/susceptibility.