PCYT1B and cancer: In the recent phase I/II Pegylated recombinant human Arginase (BCT-100) in Relapsed/refractory cancers of Children and young adults (PARC) study exploring the safety and activity of BCT-100 in 49 children and young adults with relapsed/refractory cancers, Grade 3 or higher toxicities were rare, and while no patients exhibited a complete response, some patients, including three with high-risk neuroblastoma, maintained stable disease, notable given their confirmed disease progression at time of enrolment [10].