Privately held U.S. cold-storage medicalshipper Marken is exploring a sale that could value it at morethan $1 billion, including debt, according to people familiarwith the matter.

The move illustrates how a pickup in demand for outsourcedpharmaceutical services and drug shipping has reversed thefortunes of a company that previously struggled with fiercecompetition from other logistics groups and lower levels ofresearch and development spending by drug makers.

Marken, which ships vaccines and blood from clinical trialsaround the world, is working with investment bank UBS Group AG on an auction process, the people said this week.

The company, which has 12-month earnings before interest,taxes, depreciation and amortization of around $100 million,could attract interest from large logistics companies such asUnited Parcel Service Inc and FedEx Corp, aswell as private equity firms, the sources said.

The process is still in its early stages and no deal may bereached, the people added, asking not to be identified becausethe sale process is confidential.

Marken, United Parcel Service and FedEx did not respond torequests for comment. UBS declined to comment.

Marken was taken over four years ago by a consortium oflenders who helped finance the acquisition of the company in2009 by Apax Partners LLP for 1 billion pounds ($1.32 billion). Apax lost its 600 million pound investment in the financialrestructuring.

Since then, specialty pharmacies and distributors havebenefited from a wave of innovative new drugs that often requirecomplex handling, including prominent new treatments that cancure Hepatitis C.

At the same time, life sciences companies have increasinglyoutsourced research spending to contractors, creating moreopportunities for firms like Marken.

Marken, which is based in Durham, North Carolina andChiswick, England, has expertise in distributing products thatare highly sensitive to temperature, including products thatneed to be stored at below minus 100 degrees Fahrenheit. (Reporting by Carl O'Donnell and Lauren Hirsch in New York,;additional reporting by Mike Stone in New York; Editing byAndrew Hay)