Daraprim is a relatively simple compound and typically costs $12.99 AUD ($10) for fifty tablets in Australia. However, Shkreli's company, Turing Pharmaceuticals, has the exclusive rights to distribute the specific Daraprim formulation in the USA (it's known as Pyrimethamine elsewhere), even though the drug was developed in 1953, and is long out of patent.
To get a new version approved, a company would have to compare it Turing's FDA-approved product with their permission, which isn't likely -- the company limits sales to doctors and pharmacies, making it difficult to reverse-engineer. Pharma companies would therefore need to go through an onerous approval process that probably wouldn't be worth it, considering that less than 10,000 Daraprim prescriptions are written in the US per year. (The US uses a "closed distribution" system which differs from most other countries.)
Though the open source Daraprim literally debunks Shkreli's premise that the drug is "underpriced" (supply and demand aside), it probably won't directly help anyone. Shkreli himself dismissed the work with a tweet, saying, "how is that showing anyone up? Almost any drug can be made at small scale for a low price. Glad it makes u feel good tho [sic]."
However, that doesn't mean that the exercise was useless. In fact, the students didn't just follow a recipe, they actually reverse-engineered the drug, checking their progress using spectral analysis on each new compound.
They also posted the work on Github, letting experts from the Open Source Malaria Consortium (OSM) (endorsed by Bill Gates) provide some help. For instance, the process used to manufacture Daraprim would be dangerous for students to replicate in a small high school lab. "They had to change things as some reagents were nasty and dangerous so some invention was needed on their part," said Todd.
After achieving a "beautiful" spectrograph, they finished with 3.7 grams of pure pyrimethamine, worth about $110,000 on the US market, and presented the results at a prestigious symposium. The OSM also posted a guide for making the drug that could help anyone else who wanted to try. That's quite an accomplishment for 16- and 17-year-old students, even if they can't actually sell it. And they sort of proved that as tempting as it is to hate Shkreli, he's merely profiting from a US system that's much friendlier to pharmaceutical companies than other countries.