ABSTRACT
The understanding of aberrant molecular pathways that result in gastrointestinal stromal tumors (GISTs) and the rapid development of molecular therapies that target these pathways represent one of the great milestones in translational oncology. The story of GIST is unique in that targeted molecular therapy was successfully applied in clinical therapeutics, with dramatic results redefining the management of these traditionally chemotherapy-resistant tumors. We briefly review the molecular biology and clinical presentation of GIST and then discuss the adjuvant and neoadjuvant use of tyrosine kinase inhibitors in early-stage GIST and their use in metastatic disease. Newer therapeutic advances in the rapidly changing field of GIST management are also discussed.
Subject(s)
Gastrointestinal Neoplasms/drug therapy , Gastrointestinal Stromal Tumors/drug therapy , Gastrointestinal Neoplasms/diagnosis , Gastrointestinal Neoplasms/pathology , Gastrointestinal Stromal Tumors/diagnosis , Humans , Molecular Targeted Therapy , Neoadjuvant Therapy , Neoplasm Metastasis , Prognosis , Protein-Tyrosine Kinases/antagonists & inhibitorsABSTRACT
MK-5046 is an orally active, potent, selective agonist of the orphan G protein-coupled receptor bombesin receptor subtype-3 (BRS-3) that is under evaluation for treatment of obesity. We report the safety, tolerability, pharmacokinetics, and pharmacodynamics of oral doses of MK-5046 (10-160 mg) in a double-blind, randomized, placebo-controlled study in healthy and obese male volunteers. MK-5046 exposure increased dose proportionally, and MK-5046 was eliminated with an apparent terminal half-life of 1.5 to 3.5 hours. Single doses transiently increased blood pressure. Patients reported adverse events (erections and feeling hot, cold, and/or jittery) that coincided with time of occurrence (T(max)) and increased with increasing dose. No changes were observed in body temperature, heart rate, plasma glucose levels, or feelings of hunger/satiety. The blood pressure and thermal experiences attenuated with a second dose 6 hours after the first. Additionally, the erections suggest a possible, unanticipated, role for BRS-3 in reproductive physiology. Oral administration of MK-5046 achieves plasma concentrations that are projected to activate BRS-3 and therefore should be suitable for exploring its biological role in humans.
