Vancomycin and Ustekinumab Combination Therapy in Acute Ulcerative Colitis.

The role of antibiotics in the treatment of ulcerative colitis is limited. We present a case of a 25-year-old woman who presented with a flare of ulcerative colitis after an episode of infectious gastroenteritis on a background of known primary sclerosing cholangitis. After the flare, she experienced persistent abdominal pain and diarrhea associated with elevated fecal calprotectin and deep rectosigmoid ulcerations on endoscopy. After unsuccessful trials of vedolizumab, infliximab, and tofacitinib, the patient was commenced on ustekinumab, tacrolimus, and oral vancomycin. Tacrolimus was ceased successfully, but while on maintenance ustekinumab therapy, 2 attempts to cease vancomycin resulted in symptom recurrence and rising fecal calprotectin that improved with vancomycin recommencement. To date, the patient has been on vancomycin continuously for 18 months and remains clinically well with colonoscopy demonstrating inactive colitis. This case highlights how vancomycin may be beneficial in the management of treatment-refractory ulcerative colitis as an adjunct to biologic therapy.

Relationship Between Serum Ustekinumab Trough Concentration and Clinical and Biochemical Disease Activity: A Real-World Study in Adult Patients with Crohn's Disease.

BACKGROUND AND OBJECTIVES: The role of therapeutic drug monitoring for ustekinumab in the treatment of Crohn's disease has not been defined. This study aimed to explore the relationship of serum ustekinumab trough concentration (UTC) with clinical and biochemical disease outcomes in a real-world setting. METHODS: We performed a retrospective analysis of Crohn's disease patients treated at a single tertiary centre. Ustekinumab was given as a single intravenous induction dose, followed by maintenance subcutaneous injections every 4 to 8 weeks. Rates of clinical remission (Harvey-Bradshaw Index ≤ 4), biochemical remission (C-reactive protein < 5 mg/l and faecal calprotectin < 150 µg/g) and complete remission were assessed at baseline and at the time of UTC testing during maintenance therapy. The association between baseline variables and UTC was tested using linear regression. We also performed an external validation analysis of UTC cut-offs established in four previously published studies. RESULTS: This study included 43 patients. Compared to 8-weekly dosing, a 2.49- and 2.65-fold increase in UTC was associated with 6-weekly and 4-weekly dosing respectively. However, there was no significant difference in clinical, biochemical or complete remission among the dosing groups. An external validation of previously published optimal UTC cut-offs found low predictive value for our patient population. CONCLUSIONS: In this study, dosing interval was the only determinant significantly associated with a higher UTC for patients on maintenance ustekinumab therapy. While a higher UTC may be achieved with dose escalation, it was not associated with improved rates of clinical or biochemical response in our cohort.