Now that hands have been shaken, observers have been reacting to Sanofi-Aventis' $20.1 million acquisition of Genzyme Corp, and most of them like what they see.

Sanofi stockholders were certainly impressed and the stock ended the day up 3.5% and analysts at Deutsche Bank saw the deal as positive. In a research note, they wrote that “conclusion of the Sanofi-Genzyme saga is a positive outcome for Sanofi shareholders, in our view, and likely to result in relief that management has remained diligent in its view of the appropriate valuation".

They went on to say the deal adds a "leading growth platform in rare diseases, improving Sanofi’s US presence, diversifying its business, and potentially leveraging the areas of Genzyme which lack critical mass", notably oncology. Tim Anderson at Sanford Bernstein said the purchase furthers the French drugmaker's goal of having "a broad collection of long-lived assets…and Genzyme’s revenue streams should be more durable than those of eg a pure small molecule drug franchise", as the rare disease area is less competitive.

At least at the moment. However, Mr Anderson noted that “future potential competitors, like Pfizer and Protalix or GlaxoSmithKline, may elect to compete on price to capture share" and warned of “possibility that Sanofi does not execute successfully on integrating Genzyme (at least on the rare drug side), because the physician/patient/drug company dynamic is much different than what Sanofi may be used to with more routine pharmaceutical products.”