Clinical trial design in neurofibromatosis type 1 as a model for other tumor predisposition syndromes

Up to 10% of all pediatric cancer patients may have an underlying germline mutation which predisposed them to develop a malignancy. With more patients being tested for and diagnosed with genetic tumor predisposition syndromes, there has been improved characterization of their many nonmalignant manifestations. However, designing and implementing clinical trials to treat the nonmalignant tumor and non-tumor manifestations of these syndromes poses many unique challenges. Unlike trials for malignancies where tumor response and survival can be used as straightforward trial endpoints, the nonmalignant manifestations are often chronic, evolve more slowly over time, and may not be immediately life-threatening. Therefore, they will likely require a different approach to both testing and treatment with a focus on more functional and patient-reported outcome trial endpoints. The recent success of treatment trials for the benign tumors plexiform neurofibromas in the tumor predisposition syndrome neurofibromatosis type 1 (NF1) can be used as a model for the development of clinical trials in other tumor predisposition syndromes. In this article, we review the unique challenges associated with targeting the nonmalignant aspects of these conditions as well as some of the lessons learned from the NF1 experience which may be applied to other syndromes in the future.