Should open access be extended to non-publicly funded research?

A recent article by Cory Doctorow in The Guardian has caused me to stop and rethink a basic view I’ve held for a while…
I think it is a no-brainer that the results of publicly-funded research should be required to be made openly accessible. What the public has paid for through taxes belongs to the public – they should not have to pay again to read the results.
…But I have always considered the results of research that private companies invest in to be theirs alone to decide how to disseminate – if at all. However, Doctorow makes a very good point that some private research results should be required to be open for ethical reasons (that could mean life or death!):
“The reason pharma companies should be required to publish their results isn’t that they’ve received a public subsidy for the research. Rather, it is because they are asking for a governmental certification saying that their products are fit for consumption, and they are asking for regulatory space to allow doctors to write prescriptions for those products. We need them to disclose their research – even if doing so undermines their profits – because without that research, we can’t know if their products are fit for use.”
Pharmaceutical companies have long suppressed results that would reflect negatively on their products. They have an ethical obligation to disclose ALL results of drug tests. This is not just their bottom line that we are talking about – but someone’s health and possibly their life.