In his first press conference since being elected to the position, incoming President Donald Trump targeted the biotech and pharmaceutical sector.

Trump insinuated that not only would he work to bring production of drugs back to the U.S., but that pharmaceutical companies are "getting away with murder" on pricing. The iShares Nasdaq Biotechnology ETF (IBB) - Get Report sank more than 3% in response, and the SPDR S&P Biotech ETF (XBI) - Get Report retreated 4%.

"He doesn't seem to know about the Trump Rally, he is essential to the Trump Rally,' TheStreet's Jim Cramer said on CNBC's "Squawk on the Street" Thursday morning. "Especially, because some of the most recent leadership has been biotech after the J.P. Morgan Conference."

Cramer found Trump's comments regarding the sector to be "totally in keeping" with what Trump does. "He said he was going to go after them during the campaign."

Trump vowed to "bring down drug prices," during his interview with Time Magazine for the "Person of the Year" cover story.

"This man has not demonstrated that he says something and then he forgets about it. This industry has had him fixated, he does not like the way that the government does its bidding," Cramer noted.

Furthermore, Cramer said investors should keen in on responses like Allergan's (AGN) - Get Report CEO Brent Saunders, regarding the Trump press conference.

"Unless you see genuine rollbacks and price concessions given to the government, this isn't going to end, which is why this sector is barely investable, barely ," Cramer contended.

The U.S. spent $325 billion on pharmaceutical drugs in 2015.

(Allergan is held in Jim Cramer's charitable trust Action Alerts PLUS. See all of his holdings with afree trial.)