Mytesi® (crofelemer 125 mg delayed-release tablets) is an FDA approved anti-secretory anti-diarrheal with a novel mechanism of action (MOA). Crofelemer, the active ingredient in Mytesi®, is a botanical drug substance extracted and purified from latex from the bark of Croton lechleri, a tree that is sustainably harvested in the Amazon rainforest. The mechanism of action of Mytesi® does not affect gut motility, peristalsis or intestinal transit time. Mytesi® is the first oral prescription pharmaceutical approved under the FDA’s botanical guidance.
Mytesi® is indicated for the symptomatic relief of non-infectious diarrhea in adult patients with HIV/AIDS on anti-retroviral therapy (ART).
The recommended dose of Mytesi® is one 125 mg delayed-release tablet taken orally two times a day.
Efficacy: The ADVENT trial, a randomized, double-blind, placebo-controlled, multi-center trial, established the efficacy and safety of Mytesi® in 374 HIV/AIDS patients experiencing frequent diarrhea for one month or more. Entry criteria required use of antiretroviral therapy and ruling out infectious diarrhea. Patients were randomized to receive Mytesi® (crofelemer) 125mg twice a day or placebo for 4 weeks followed by a 20-week open-label extension.
4-Week Placebo Controlled Phase: Patients randomized to Mytesi® 125 mg bid had an average baseline of 19 watery stools per week. Mytesi® produced a statistically and clinically significant reduction in watery diarrhea (defined as the proportion of subjects with ≤ 2 watery stools per week for at least half of the 4-week placebo-controlled period). Patients receiving Mytesi® had a significantly greater proportion of responders, approximately twice as many as the patients receiving matching placebo (17.6% vs 8%, p<0.01).
20-Week Open-Label Extension Phase: Of the 134 patients randomized to Mytesi® 125 mg bid in the placebo-controlled phase, 116 (87%) chose to continue with Mytesi® in the 20-week open-label extension phase. A total of 225 patients entered the 20-week open-label extension, and the percentage of patients that were Mytesi® responders (defined as < 2 watery stools per week) ranged from 40% to 56% over this 20-week period, indicating that the anti-diarrheal effect of Mytesi® appeared to be maintained.
Safety: Mytesi® was well tolerated in the ADVENT trial. The most common adverse reaction with Mytesi® and placebo were upper respiratory infection (5.7% vs 1.5%), bronchitis (3.9% vs. 0%), cough (3.5% vs. 1.1%), flatulence and increased bilirubin (3.1 vs. 1.1%, respectively).
Mechanism of Action
Mytesi® (crofelemer 125 mg delayed-release tablets) is an inhibitor of both the cyclic adenosine monophosphate (cAMP)-stimulated cystic fibrosis transmembrane conductance regulator (CFTR) chloride ion (Cl¯) channel, and the calcium-activated Cl¯ channels (CaCC) at the luminal membrane of enterocytes. The CFTR Cl¯ channel and CaCC regulate Cl¯ and fluid secretion by intestinal epithelial cells. Crofelemer acts by blocking Cl¯ secretion and accompanying high volume water loss in diarrhea, normalizing the flow of Cl¯ and water in the GI tract. Mytesi® is a non-opiate and non-antibiotic anti-secretory agent that has minimal oral absorption.
Important Safety Information
Mytesi® (crofelemer 125 mg delayed-release tablets) is approved for the symptomatic relief of non-infectious diarrhea in adult patients with HIV/AIDS on antiretroviral therapy. Rule out infectious etiologies of diarrhea before starting Mytesi® in order to avoid the risk of potential worsening of disease due to delay of appropriate therapy. The most common adverse events (incidence ≥ 3%) reported in Mytesi® clinical trials were upper respiratory tract infection, bronchitis, cough, flatulence, and increased billirubin.