A surveillance study is conducted to assess the efficacy and safety of tolvaptan, a drug currently being used in the clinical setting for treating heart failure with volume overload. The study enrolls 8,300 patients with a variety of medical comorbidities who received tolvaptan once daily in the morning for 2 weeks. Results showed that tolvaptan demonstrated aquaretic efficacy in patients with diuretic-resistant volume overload, but that hypernatremia was a complication in a small number of patients. Researchers recommended a lower dose of tolvaptan in those with normonatremia and hypokalemia to prevent hypernatremia. Which of the following best describes this type of study?

Question

A surveillance study is conducted to assess the efficacy and safety of tolvaptan, a drug currently being used in the clinical setting for treating heart failure with volume overload.  The study enrolls 8,300 patients with a variety of medical comorbidities who received tolvaptan once daily in the morning for 2 weeks.  Results showed that tolvaptan demonstrated aquaretic efficacy in patients with diuretic-resistant volume overload, but that hypernatremia was a complication in a small number of patients.  Researchers recommended a lower dose of tolvaptan in those with normonatremia and hypokalemia to prevent hypernatremia.  Which of the following best describes this type of study?

Quizplus · Accepted Answer

The clinical trials process addresses whether new treatments (eg, drugs, procedures) are effective and safe for their intended use (ie, treatment of a disease) in the target population (eg, subjects with the disease of interest). New treatments go through several research phases; some phases involve no human subjects (ie, preclinical studies) and some involve few (ie, phase I and II trials) or many (ie, phase III and IV trials) human subjects. Phase IV trials are postmarketing surveillance studies that assess for rare or delayed adverse effects of newly approved treatments on the market. They are conducted on larger patient populations for longer periods of time compared to other types of clinical trials. As such, they have substantial statistical power and can identify adverse effects that were not observed in earlier trials; they may also evaluate long-term effectiveness of new treatments and assess treatment response in different subpopulations (eg, based on sex, comorbidities). Results from phase IV trials may lead to restrictions in use or a withdrawal of treatment from the market. In this example, a postmarketing surveillance study was conducted to determine if the efficacy and safety features established in controlled trials for a treatment (ie, tolvaptan) in a particular population (ie, heart failure subjects with volume overload) extend to real-world clinical settings. The study revealed a treatment complication in the clinical setting (ie, hypernatremia) that warranted a use restriction (ie, lower dose) in a specific population (ie, those with normonatremia and hypokalemia). This study describes a phase IV trial. (Choice A) Contrary to phase I, II, III, and IV trials, which include human subjects, preclinical studies do not involve human subjects. (Choices B, C, and D) Contrary to phase I, II, and III trials, which are designed to evaluate human safety and treatment efficacy before any treatment can be marketed to the public, phase IV trials are designed to reevaluate after-market human safety and treatment efficacy. Educational objective: Phase IV trials are postmarketing surveillance studies that assess the adverse effects and long-term effectiveness of newly approved treatments on the market. Results from phase IV trials may lead to restrictions in use or a withdrawal of treatment from the market.

A Surveillance Study Is Conducted to Assess the Efficacy and Safety