title: NCI-RTOG translational program strategic guidelines for the early-stage development of radiosensitizers.
abstract: The addition of chemotherapeutic agents to ionizing radiation has improved survival in many malignancies. Cure rates may be further improved by adding novel targeted agents to current radiotherapy or radiochemotherapy regimens. Despite promising laboratory data, progress in the clinical development of new drugs with radiation has been limited. To define and address the problems involved, a collaborative effort between individuals within the translational research program of the Radiation Oncology Therapy Group and the National Cancer Institute was established. We discerned challenges to drug development with radiation including: 1) the limited relevance of preclinical work, 2) the pharmaceutical industry's diminished interest, and 3) the important individual skills and institutional commitments required to ensure a successful program. The differences between early-phase trial designs with and without radiation are noted as substantial. The traditional endpoints for early-phase clinical trials-acute toxicity and maximum-tolerated dose-are of limited value when combining targeted agents with radiation. Furthermore, response rate is not a useful surrogate marker of activity in radiation combination trials.Consequently, a risk-stratified model for drug-dose escalation with radiation is proposed, based upon the known and estimated adverse effects. The guidelines discuss new clinical trial designs, such as the time-to-event continual reassessment method design for phase I trials, randomized phase II "screening" trials, and the use of surrogate endpoints, such as pathological response. It is hoped that by providing a clear pathway, this article will accelerate the rate of drug development with radiation.
authors.affiliation: Department of Radiation Oncology, Sheba Medical Center, Tel HaShomer, Israel. yaacovla@gmail.com
authors.forename: Yaacov Richard
authors.initials: YR
authors.lastname: Lawrence
authors.forename: Bhadrasain
authors.initials: B
authors.lastname: Vikram
authors.forename: James J
authors.initials: JJ
authors.lastname: Dignam
authors.forename: Arnab
authors.initials: A
authors.lastname: Chakravarti
authors.forename: Mitchell
authors.initials: M
authors.lastname: Machtay
authors.forename: Boris
authors.initials: B
authors.lastname: Freidlin
authors.forename: Naoko
authors.initials: N
authors.lastname: Takebe
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Curran
authors.forename: Soren M
authors.initials: SM
authors.lastname: Bentzen
authors.forename: Paul
authors.initials: P
authors.lastname: Okunieff
authors.forename: C Norman
authors.initials: CN
authors.lastname: Coleman
authors.forename: Adam P
authors.initials: AP
authors.lastname: Dicker
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology; D014408:Biomarkers, Tumor / Q000378:metabolism; D015687:Cell Hypoxia / Q000187:drug effects / Q000528:radiation effects; D002986:Clinical Trials as Topic / Q000379:methods* / Q000592:standards / Q000639:trends; D017321:Clinical Trials, Phase I as Topic / Q000379:methods; D017322:Clinical Trials, Phase II as Topic / Q000379:methods; D054697:Cytostatic Agents / Q000008:administration & dosage / Q000494:pharmacology; D003603:Cytotoxins / Q000008:administration & dosage / Q000494:pharmacology; D004249:DNA Damage / Q000187:drug effects / Q000528:radiation effects; D004260:DNA Repair / Q000187:drug effects / Q000528:radiation effects; D004195:Disease Models, Animal; D019583:Dose Fractionation, Radiation; D004334:Drug Administration Schedule; D015195:Drug Design; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007155:Immunologic Factors / Q000008:administration & dosage / Q000494:pharmacology; D058990:Molecular Targeted Therapy / Q000379:methods; D054547:National Cancer Institute (U.S.); D009369:Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000532:radiotherapy*; D011838:Radiation-Sensitizing Agents / Q000008:administration & dosage / Q000494:pharmacology; D011878:Radiotherapy / Q000009:adverse effects; D012107:Research Design; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D057170:Translational Research, Biomedical / Q000379:methods* / Q000592:standards / Q000639:trends; D014481:United States
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D054697:Cytostatic Agents; D003603:Cytotoxins; D007155:Immunologic Factors; D011838:Radiation-Sensitizing Agents; D066246:ErbB Receptors