Pharmacy benefit manager Express Scripts Holding Co. announced that CFO Cathy R. Smith has stepped down after only 11 months on the job and will be replaced on an interim basis by James M. Havel, formerly the finance chief at Major Brands Holdings.

Smith is leaving Express Scripts to pursue other interests, the company said in a regulatory filing Monday, but will stay on into the first quarter of 2015 to “facilitate a smooth and orderly transition.” She moved to Express Scripts from Wal-Mart International in January.

Cathy R. Smith

“Ms. Smith’s separation from the company is not the result of any issue, concern or disagreement with the company’s accounting, financial reporting or internal control over financial reporting,” Express Scripts said.

Havel, 60, will take over as interim CFO on January 2. He was hired by Major Brands, a beverage distributor, in April 2012 after previously running his own financial consulting firm and spending 34 years at Ernst & Young, where he began his career as a certified public accountant.

Express Scripts said it had begun a search for a permanent CFO and will make an announcement once a successor is appointed.

As MarketWatch reports, the company, which manages drug-benefit programs for health plans and corporate customers, has been struggling to integrate its $29 billion acquisition of former rival Medco Health and to deal with customer losses. In October, it reported a 36% increase in profit, reflecting slightly lower revenue but better margins.

On Dec. 10, Express Script’s board increased the number of shares it can buy back by 65 million to a combined authorization of 205 million shares.

Havel will be paid a base annual salary of $725,000 along with a bonus for 2015 of up to 100% of that amount. He will also receive a one-time $110,000 signing bonus and a $2.5-million stock award, which will vest in three years. Express Scripts said he will also be eligible for annual equity awards.

The company’s shares were down about 3% at $80.10 in trading Tuesday.