Rationale for Regorafenib Combination Study in Pediatric Rhabdomyosarcoma

Dieter Zopf, Principal Scientist at Bayer AG, Research and Development, Pharmaceuticals, Oncology, discusses the rationale for a study of regorafenib (Stivarga) combinations in pediatric patients with rhabdomyosarcomas (RMS).

In a study of 13 compounds in combination with regorafenib, investigators sought to find the most favorable response in subcutaneous xenograft models of pediatric RMS. Zopf explains that in Europe, there is a requirement by the regulatory agencies that a pediatric investigation plan (PIP) must be done. Regorafenib is currently approved for gastrointestinal stromal tumors (GIST), which do occur in pediatric patients, but not frequently. Investigators failed to get a PIP for GIST due to low enrollment, so a different approach had to be formulated.

Zopf says that in order to get approval to run a trial of regorafenib without a PIP, investigators were requested to test regorafenib in multiple tumors to see whether antitumor activity in preclinical and clinical settings could be achieved. There was some activity observed in RMS, so the investigators went back to the European Medicines Agency and agreed to look into regorafenib in pediatric RMS.