Conflict of interest: E-M. Jutant, L. Tu, R. Thuillet, V. Picard and A. Huertas have no conflicts of interest to disclose. C. Guignabert reports grants from Acceleron, Janssen, ShouTi and MSD to his institution, and personal fees from MSD. F. Parent reports grants from Acceleron, Bayer, Merck and Janssen to her institution, and personal fees from Bayer and MSD, outside the submitted work. O. Sitbon reports grants to his institution from Janssen, Bayer, MSD and GSK, and personal fees from Janssen, MSD, Acceleron, Gossamer Bio, Bayer, Ferrer, AOP Orphan and GSK. M. Humbert reports grants to his institution and personal fees from Acceleron, Janssen and Merck, and personal fees from AOP, Acceleron, Janssen and Merck, outside the submitted work. L. Savale reports grants to his institution and personal fees from Acceleron, Janssen and Merck, and personal fees from Bayer, Janssen and Merck, outside the submitted work.