Do Libertarians believe in an unregulated pharma industry? If not, how controlling should the government be of pricing of medications?

These are two different loaded questions because pricing has nothing to do with the approval process for new medical products and stipulation of what diseases or disorders they can be marketed for (i.e. what they were tested for in clinical trials), which is usually what people mean by regulation because the FDA does not have a pricing division. If you are trying to ask how the government can deter price gouging without the usual knee jerk reaction of direct price controls, I outlined them in two previous posts. The government enables this predatory behavior by granting pharma corps legal monopolies over certain medical products called patents and extensions of those legal monopolies, in whole or in part, called evergreening. Assuming the Pharma industry is allowed to continue operating within a capitalist framework, in which intellectual property that is inseparable from capitalism exists, there are several ways governments can wrangle back some of the power they delegated to price gouging pharma corps without directly controlling pricing or production.

1.) Abolish evergreening: As I explained in Patents and Evergreening: The Reason for Unaffordable Drug Prices, patentees can file secondary applications with USPTO for any minor and incremental changes of the primary patented product to extend the life of their monopoly over that product prior to its expiration. Sanofi used this to effectively extend their monopoly over their injectable long-acting insulin product the primary patent of which expired in 2015. Of course, evergreening is not only enforced by US law but also international trade agreements with other countries and trade blocs like the EU so it's likely entirely infeasible within the current political landscape in which politicians and bureaucrats remain deferential to industry not only to stay in the graces of their donors but also to avoid the cudgel corporations wield through ISDS.

These next two concern authority given to government IP holders by the Bayh-Dole which I also covered in:

2.) Reinstate the Reasonable Pricing Clause of the Bayh-Dole Act: this is entirely within the realm of possibility for medical products that were developed using research funded by NIH grants, patented by NIAID scientists and licensed out to pharmaceutical companies.

3.) Exercise March-In-Rights: the Bayh-Dole Act allows federal agencies like HHS to retain certain rights over products produced using research funded by their grant money and leverage the IP they or their grantees license to pharma corps which includes granting such licenses to more responsible applicants (e.g. other than the price gouger) who will make the product available to the public on reasonable terms (i.e. affordable to the people who need it to survive).

4.) Allow generic competition against price gougers: the Drug Price Competition and Patent Term Restoration Act which allows generic drug companies to develop their own analogs/biosimilars of patented drugs without liability for patent infringement, but this would require repealing the Biologics Price Competition and Innovation Act included in the ACA that guarantees 12 years of market exclusivity to brand drug makers, even if they have no patent, and allows patent holders to bring frivolous patent infringement claims without evidence. It would also require closing loopholes in the original Drug Price Competition and Patent Term Restoration Act that allows drug makers to pay to delay generic competition and deny access to samples required to make generic analogs.

5.) Expediting IP Waivers and Compulsory Licenses: In Vaccine Rent Seeking I outlined how patents could be used to deprive entire countries of certain medical products on the same financial basis that poor people in the global north can be deprived of certain medical products. Currently, compulsory licensing requires a separate application for each patented process and since a single patented product can have several patented processes the applicant would need file and receive approval for several applications for a single product. Reducing this to one would patented medical products easier to obtain in the global south.

I originally answered this on Quora