Cigna CEO David Cordani is trying to quell concerns that regulators will scrutinize and even block his company's acquisition of pharmacy benefits manager Express Scripts.

Experts have pointed to the Justice Department's review of AT&T's acquisition of Time Warner as an example of the scrutiny Cigna and Express Scripts could face. Both deals are vertical mergers. Critics argue that although the companies don't appear to directly compete, combining them could hurt consumers.

"There's a lot of concern and noise relative to the regulatory environment given the pendency of the AT&T deal and other deals in the transaction," Cordani told CNBC on Thursday. "We're trying to ensure it's clear that our two companies are truly complementary of each other and don't have a material overlap."

In an interview on "Squawk on the Street," Cordani declined to comment on AT&T and Time Warner's case, but he said Cigna's deal is different.

"We are not dealing with distribution and content," he said. "We are dealing with two complementary companies: one that is a health services company, and one that is a pharmacy service company. That has very little overlap for any traditional antitrust measures, and we believe that as that becomes understood with facts, this will not only be approved but will be approved this year."

Cordani said the company anticipated the Justice Department would review the deal. The agency requested more information from Cigna and Express Scripts, which Cordani said was not surprising given the size of the deal.

The request was "essentially consistent" with what they expected, he said, adding that Cigna is "actively engaged" with the Justice Department.

Last year, the department blocked Anthem's proposed acquisition of Cigna, one of a handful of health insurance mergers the regulator stopped on antitrust grounds. The department will now review a new round of health-care deals, including drugstore chain and pharmacy benefit manager CVS Health's acquisition of health insurer Aetna.