PARIS ( TheStreet) -- Sanofi ( SNY), the French drugmaker, has reached an agreement in principle on the outlines of a deal to buy Genzyme ( GENZ), according to multiple reports.

The deal will include a contingent value right based on the performance of Genzyme's Lemtrada, a multiple sclerosis drug, Reuters reports, citing sources. A CVR gives shareholders an added benefit if an acquired company hits a future benchmark.

Sanofi and Genzyme, the U.S. biotechnology company, could reach a deal within a week or two, Reuters reports. Just last week, Sanofi said "significant differences" remained on the potential CVR.

Sanofi's offer of $69 a share, or $18.5 billion, for Genzyme ends on Feb. 15.

Sanofi and Genzyme disclosed earlier Monday in a regulatory filing that Sanofi has begun due diligence on Genyzme's books.

-- Written by Joseph Woelfel

>To contact the writer of this article, click here: Joseph Woelfel

>To submit a news tip, send an email to: tips@thestreet.com.

If you liked this article you might like

Biotech Mailbag: Buy Dip in T2 Biosystems?

FDA Official Calls for Ending Codeine Use in Kids Cough Products

Big Drug Makers Could Face More Pressure on Codeine Remedies for Kids

Sanofi Has Good Potential Upside

European Pharma Companies Slip on MS Pricing Probe