"That's why I was excited about a conditionally replication-competent adenovirus, because one of the major problems of adenovirus gene therapy, and adenovirus therapy in general, has been the problem with trying to ensure that all of the cancer cells get infected," Yarbrough said.
He points out that the clinical advantage of using a mutated adenovirus has been observed in many experimental models. And in one clinical study, the virus was injected directly into recurrent tumors that had failed all other treatments. Patients also received chemotherapy with cisplatin and 5-fluoraouracil. The study resulted in roughly 60% of tumors responding to treatment.
The new multi-center clinical trial is designed to treat recurrent head and neck squamous cell cancer that is amenable to direct injection. Some patients will be randomized to receive chemotherapy alone and others randomized to chemotherapy plus adenovirus. Pfizer, Inc sponsors this trial.
"The nice thing about most biological therapies, including this adenovirus, in combination with standard therapy is they don't increase toxicity to the patient. Research also suggests that adenovirus and chemotherapy may have synergistic anti-tumor activity," Yarbrough said.