French group Sanofi and US drugmaker Bristol-Myers Squibb have modified their ancient alliance after losing patent protection for the blockbuster Plavix and Avapro/Avalide in many major markets.

Under the revised terms, Sanofi has regained worldwide rights to Plavix (clopidogrel) except in the US and Puerto Rico, as well as rights to Avapro/Avalide (irbesartan) in all markets.

In return, B-MS will get a royalty stream on sales of the drugs in Sanofi's new territories until 2018, as well as a one-off terminal payment of $200 million in December that year. 

Plavix rights in the US and Puerto Rico will continue unchanged under the terms of the existing deal through December 2019, the firms said.

Explaining the rationale behind the move, Hanspeter Spek, President of Global Operations at Sanofi, noted that the revised agreement "further supports Sanofi’'s strategic priorities while continuing to offer the clinical benefits of these well-established products".

While for B-MS, it "simplifies operations", enables the firm to focus on delivering its R&D portfolio, and sets the foundation for future success”, said chief executive Lamberto Andreotti.

In addition, the companies have resolved all disputes in relation to alliance, including the disruption of the supply of Avalide in the US in 2011, for which B-MS will make to Sanofi a one-time payment of $80 million.