The development of new cancer therapies is essential to offer new options to patients with tumors that do not respond to standard treatments. Among these, research is studying the use of oncolytic viruses, i.e. viruses that are introduced into the tumor and are capable of eliminating it directly or of attracting immune cells that fight against tumor cells. In this sense, a phase 1 clinical trial led by the Childhood Cancer and Blood Disorders group at Vall d'Hebron Research Institute (VHIR) has demonstrated the feasibility and safety of using a herpesvirus in patients with pediatric solid tumors. The results have been published in Frontiers in Pediatrics.

The use of different oncolytic viruses has so far been tested in some tumors. For example, the efficacy of talimogene laherparepvec (T-VEC) immunotherapy, based on a herpesvirus, has been demonstrated in a phase 3 trial in adult melanoma patients. For this purpose, the virus is modified to eliminate genes related to its virulence in the nervous system.

In the pediatric setting, the safety of different viruses has been previously analyzed in Phase 1 trials, but this is the first study using T-VEC in children and adolescents with extracranial solid tumors. "Despite the improvements in survival in childhood cancer in recent years, the prognosis of patients with solid tumors in relapse or unresponsive to treatment is poor and it is necessary to continue working to find new therapies", states Dr. Lucas Moreno, head of the Pediatric Oncology and Hematology Service at Vall d'Hebron University Hospital and of the Children's Cancer and Hematological Diseases group at VHIR.

The study presented now consists of a phase 1 trial involving 15 patients from different centers in Europe and North America. The participants were patients aged 2 to 21 years with solid tumors that did not respond to the usual treatments or for which there was no effective therapy. "This is a complicated therapy to administer and, thanks to this work, we have proven the feasibility of performing it. In addition, we have seen that it is safe, since most of the patients had only mild undesirable effects, such as fever, vomiting or headache", explains Dr. Lucas Moreno.