Phase II Study of a Multi-center Randomized Controlled Trial to Evaluate Oral Vitamin B12 Treatment for Vitamin B12 Deficiency After Total Gastrectomy in Gastric Cancer Patients.

BACKGROUND/AIM: This prospective multi-central randomized phase II trial evaluated the efficacy and safety of oral Vitamin B12 500 μg/day replacement compared with oral Vitamin B12 1,500 μg/day in patients with Vitamin B12 deficiency after total gastrectomy for gastric cancer.

PATIENTS AND METHODS

Patients were randomly assigned to receive oral Vitamin B12 500 μg/day or Vitamin B12 1,500 μg/day in a 1:1 ratio with a minimization method. The primary endpoint was the incidence of a normal serum Vitamin B12 level at three months after treatment.

RESULTS

From January 2018 to December 2021, 3 institutions collaborated with the present study, and 74 patients were registered from these 3 institutions. The study was prematurely closed due to poor accrual after reaching almost 50% of its goal. Among the 74 recruited patients, 36 were allocated to the Vitamin B12 500 μg/day arm and 38 to Vitamin B12 1,500 μg/day arm. The incidences of patients with a normal Vitamin B12 level at 3 months (serum Vitamin B12 level >200 pg/ml) were 91.7% (33/36) in the Vitamin B12 500 μg/day arm and 100% (38/38) in the Vitamin B12 1,500 μg/day arm (p=0.3587). The types of clinical symptoms with Vitamin B12 deficiency that improved with Vitamin B12 treatment and the degree of improvement were also similar.

CONCLUSION

Although the primary endpoint of the present study was not met, it was found that oral Vitamin B12 500 μg/day replacement is as effective and safe as oral Vitamin B12 1,500 μg/day replacement for Vitamin B12 deficiency.