PARIS (REUTERS) - Sanofi has offered to buy US biotech company Translate Bio, two sources familiar with the situation said on Monday, as the French drugmaker bets on next-generation mRNA technology after setbacks in the Covid-19 vaccine race. Shares in the New York-listed biotech company soared more than 70 per cent to above US$50 in extended trading, building on the big gains in the stock as investors have piled in to the sector amid a rush to develop vaccines and treatments to tame the pandemic which has killed 4.3 million and roiled the global economy. An offer for all Translate Bio shares had been made to the US group's shareholders, the sources said. The persons declined to be identified due to the confidentiality of the talks. Translate's board was expected to meet on Monday to discuss the offer, one of the sources said. The second source said Sanofi's directors had met on Sunday to discuss the potential deal. A spokeswoman for Sanofi declined to comment and Translate Bio did not respond to requests by email and phone for comment. Financial terms of the offer were not known. Translate Bio's market value has soared fivefold since the start of the pandemic, to about US$2.2 bill...