PARIS—French drugmaker Sanofi said on Wednesday it would buy U.S. biopharmaceutical company Kadmon Holdings for 1.9 billion dollars, one month after announcing the purchase of another US biotech, Translate Bio, for $3.2 billion. Sanofi said it has offered $9.50 per share in cash for Kadmon, representing a total equity value of approximately $1.9 billion on…