Phase II trial opens for Viscum album extract adjuvant therapy in relapsed osteosarcoma

A Phase II trial has been opened to investigate Viscum album extract (Iscador® P) as adjuvant therapy for children, adolescents, and young adults (AYAs) with relapsed, resectable osteosarcoma. The primary outcome is post-relapse event-free survival at 12 months (PREFS-12). Secondary outcomes include effects on quality of life and changes in immune profiling of tumor and serum samples. The trial's sample size, comparator, and follow-up duration are not reported.

Results from a prior pilot study, referenced in the trial description, involved 9 pediatric and AYA patients. In that small cohort, the 12-month post-relapse event-free survival rate was 55%, with a median follow-up of 84 months. No effect size, p-values, or confidence intervals for this finding are reported. Safety and tolerability data for the extract in this population are not reported.

Key limitations are significant. The main finding of 55% PREFS-12 comes from a small, uncontrolled pilot study, not the newly opened Phase II trial. The trial itself has not yet generated results. The absence of reported safety data, comparator details, and statistical measures for the pilot finding limits interpretation. The practice relevance of Viscum album extract in this setting remains highly uncertain and awaits data from the controlled Phase II investigation.