UPDATE 1-Medco CEO: More drug unit sales by HMOs possible

* Says weak economy is a catalyst

* Follows WellPoint sale of unit to Express Scripts

* Cigna CEO says "actively" looking at PBM

* Cigna shares rise 7.1 pct; Medco up 1.3 pct

By Lewis Krauskopf

NEW YORK, May 28 (Reuters) - The CEO of Medco Health Solutions Inc (MHS.N: Quote, Profile, Research), the largest U.S. pharmacy benefit manager, said on Thursday he would not be surprised if other health insurers follow the lead of WellPoint Inc (WLP.N: Quote, Profile, Research) and sell off their pharmacy benefit units.

Speaking at the same investor conference, the chief of Cigna Corp (CI.N: Quote, Profile, Research) said the health insurer was "actively" evaluating at its pharmacy benefit manager. Cigna shares were up 7.1 percent, while Medco was up 1.3 percent.

Investors are speculating other transactions will follow in the wake of pharmacy benefit manager Express Scripts Inc's (ESRX.O: Quote, Profile, Research) $4.68 billion purchase of WellPoint's NextRx unit, announced in April. Express Scripts said on Thursday it cleared an antitrust hurdle for the acquisition. [ID:nN28316888]

Medco CEO David Snow said the Express Scripts-WellPoint deal was not a surprise.