NeuroPhage Pharmaceuticals, a US-based biotechnology company backed by pharmaceutical firms Shire and Mérieux, has closed a $27m series D round after securing $10m from undisclosed investors.

The company initally raised $17m in March 2014 from Shire and Mérieux Développement, the healthcare investment unit of bioresearch corporation Institut Mérieux, in the first tranche of the round.

Mérieux and Shire previously invested $6.4m in NeuroPhage’s 2013 series C round, after funding its $21.4m series B in 2012. The company’s $7m series A…