Researchers from the translational research program of the National Cancer Institute and the Radiation Therapy Oncology Therapy Group have developed new guidelines to help fast track the clinical development of targeted cancer drugs in combination with radiation therapy.
The suggested strategic guidelines, published in the Journal of the National Cancer Institute in a recent commentary with lead author Yaacov Richard Lawrence, MRCP, an adjunct Assistant Professor in the Department of Radiation Oncology at Thomas Jefferson University and Director of the Center for Translational Research in Radiation Oncology at Sheba Medical Center in Israel, offers specific steps in the preclinical and early phase clinical trial process to get well-studied and novel targeted agents into the clinic more quickly.
Over the last decade, molecular agents that target cellular survival and growth, like Erlotinib and Sunitinib, have been developed but alone have had modest effect on improved survival. Combining such targeted agents with radiation therapy, however, has the potential to improve cure rates and long-term overall survival.
"There's a missed opportunity in today's cancer care treatment," says Dr. Lawrence. "There is very promising laboratory data out there, but the clinical development of these new drugs with radiation has been limited. Here, we have put together a road map to help overcome obstacles and speed the development of new pipeline drugs with radiation."
Adding radiation therapy to existing chemotherapy agents to radiation therapy has improved survival, and the authors of the commentary, which includes Adam P. Dicker, Chair of the Department of Radiation Oncology at Jefferson, believe new targeted therapies can follow in the same path.
"We know we want to repeat that success with new biological drugs," says Dr. Lawrence. "In order to do that, we need direction, which is sorely lacking. These guidelines explicitly explain how much evidence is needed to go forward from the lab into the clinic, and furthermore how to design the clinical trials in humans."
The guidelines discuss key questions when investigating specific targeted agents and tumor types, designing new clinical trials, such as the 'time-to-event continual reassessment method design' for phase I trials, and randomized phase II "screening" trials, and the use of surrogate endpoints, such as pathological response.
It also discusses the role and purpose of preclinical studies in radiation oncology drug development and how to identify new, radiation response agents.
There are challenges to drug development with radiation, the authors explain. A major problem is the limited interest from the pharmaceutical industry in developing drugs with radiation, which is of special importance since the pharmaceutical industry fund a large amount of clinical cancer research. Furthermore, significant individual skills and institutional commitments are also required to ensure a successful program. The situation has been extenuated by the decrease in radiation biologists in recent years.
It is hoped that by providing a clear pathway, the guidelines will help the field overcome these barriers and create a focus and interest in drug development. Some new approaches, the researchers say, include combining radiosensitizers with hypofractionated (high daily dose) radiation schedules and integrating immunomodulators with radiation therapy.
"We feel passionate that a a good way to push clinical care forward for cancer patients is by combining these two types of treatment: advanced radiation treatment together with the new generation of anticancer drugs," says Dr. Lawrence. "We know where the future lies, and guidelines provide the path to bring us there."
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