Martin Shkreli and his newest adversary just had an awkward public exchange

Earlier this week, pharmacy benefits manager Express Scripts partnered with a company that makes a $1-per-pill version of Turing Pharmaceuticals' $750 per-pill drug Daraprim.

The move could undermine Turing's plan to squeeze a profit out of Daraprim, which is used to treat an infection that's harmful to people with weakened immune systems.

The drug, which is more than 60 years old, only cost $13.50 when Turing acquired it and hiked the price.

Shkreli, who spoke Thursday at the Forbes Healthcare Summit in New York, brushed off the news of a low cost competitor.

"Express Scripts emailed me begging for my business," he said.

Steve Miller, the chief marketing officer of Express Scripts didn't stand by. When the session opened for questions, Miller fired back with a question about what infectious disease doctors think of Turing's decision to increase the price of Daraprim.

To which Shkreli pointed out that Express Scripts is still accepting prescriptions for Daraprim, and then snapped: "You're the company that likes to limit innovation, we're the kind of company that likes to do it so I'm proud of what were doing."

Watch the whole awkward exchange unfold here.

After the tense session ended, Business Insider asked Miller to fact-check Shkreli's claim about the email "begging" for business. Here's what he had to say:

"We have a company called UBC, and they were doing the patient assistance program for the prior owner of Daraprim. Obviously with the change of ownership there was a renegotiation of the contract. We were more than happy to support a patient assistance program when the drug was priced at $13.50. When the price of the drug went up to $750, obviously we had to take a different approach."

"We definitely were supporting the drug in the past. We definitely have no desire to support the drug in the future, but we will not abandon the patients in the interim."

The news of Express Scripts partnership with compounding pharmaceutical company Imprimis to provide their compounded version of pyrimethamine, the active part of Daraprim. Imprimis combines pyrimethamine with leucovorin, a form of B-vitamin folic acid that's recommended to treat toxoplasmosis by the US Centers for Disease Control and Prevention.

But, this partnership with Imprimis is specific to the toxoplasmosis condition, and the small population of patients who actually need to take Daraprim.

"This is really we think this a unique situation where this could be a solution," he said. "We don't look at this as becoming a new standard."