Abstract A016: Successful design and execution of two gastric cancer chemoprevention trials in Central America and Puerto Rico
Authors: Montalvan-Sanchez Eleazar , Gonzalez-Pons Maria , Norwood Dalton , Dominguez Ricardo , Wilson Keith , Cruz-Correa Marcia , Morgan Douglas 
Published: December 2022

Gastric adenocarcinoma (GAC) is the third leading global cause of cancer mortality and leading infection-associated cancer. The high incidence regions are Latin America, East Asia, and Eastern Europe. In the U.S., GAC represents a major cancer disparity, double the incidence rates in all non-white populations, the opposite of Barrett’s Esophagus and EAC. Immigrants from high incidence regions maintain the risk profile of their nations of origin. In a paradigm shift, recent guidelines now recommend surveillance endoscopy (eg, 3 years) for patients with high-risk gastric premalignant conditions (GPMCs). Clinical trials of chemoprevention agents for patients with GPMCs are lacking. We conducted two independent, NCI DCP funded, phase II placebo-controlled chemoprevention trials in patients with GPMCs (intestinal metaplasia, atrophic gastritis). The oral agents were curcumin and eflornithine (DFMO). A highly bioavailable preparation of curcumin was used. The RCTs were conducted in Puerto Rico and rural Honduras, with important characteristics: (1) representative of Caribbean and Mesoamerican populations and linked to large U.S. immigrant populations; (2) high prevalence of H. pylori infection and GPMCs; (3) absence of turmeric and curcuminoids in the local diets; (4) proven bidirectional collaboration with academic institutions in the U.S. In the curcumin trial (NCT02782949) H. pylori negative patients were randomized to study drug or placebo for 6 months. In the eflornithine study (NCT02794428), H. pylori positive and negative subjects were randomized to study drug or placebo for 18 months, with endoscopy at baseline, and 6. 18, and 24 months. The primary outcomes were based upon changes in histologic parameters at 6 months. Principal study challenges included: (1) International and bilingual regulatory environment; (2) Strengthening of the research infrastructure, particularly in Central America; (3) Participant recruitment, eg, in the curcumin RCT in Honduras wherein only 10-15% are H. pylori negative; (4) The Covid-19 pandemic; (5) Natural disasters (3 hurricanes).

In Conclusion: Eflornithine and curcumin RCTs have been successfully completed, despite important challenges in implementation and execution. No losses to follow-up were encountered related to the pandemic or natural disasters. The south-south partnership may provide a model for chemoprevention and translational studies in Latino populations with prevalent cancers such as GAC.

Citation Format: Eleazar Montalvan-Sanchez, Maria Gonzalez-Pons, Dalton Norwood, Ricardo Dominguez, Keith Wilson, Marcia Cruz-Correa, Douglas Morgan. Successful design and execution of two gastric cancer chemoprevention trials in Central America and Puerto Rico [abstract]. In: Proceedings of the Second Biennial NCI Meeting: Translational Advances in Cancer Prevention Agent Development (TACPAD); 2022 Sep 7-9. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_2): Abstract nr A016.