Efficacy and safety of azathioprine in patients with Cronkhite-Canada syndrome: a case series from Peking Union Medical College Hospital.

Background: Cronkhite-Canada syndrome (CCS) is a rare non-hereditary chronic inflammatory disease characteristic of gastrointestinal polyps and ectodermal abnormalities. Corticosteroid therapy is the mainstay medication for CCS. Few studies indicated immunosuppressants might be the choices for patients with steroid refractory, steroid dependent or intolerant.

Aim: To examine the efficacy and safety of azathioprine (AZA) in CCS patients.

Method: We retrospectively reviewed the records of 12 CCS patients treated with azathioprine between July 2014 and October 2023 and the clinical data including demographic characteristics, treatment regimen and adverse events were subsequently collected and analyzed. The genetic variants of TPMT and NUDT15 genes were also retrospectively assessed using sanger sequencing in 11 patients.

Outcome: All patients were in active stage at baseline and 9 patients (75%) were in combination with corticosteroid. On account of the indication, 6 patients were steroid dependent or intolerant and another 6 patients needed augmentation therapy. The target dose of AZA was 1.0 to 1.5 mg/kg per day. Ten (83.3%) patients achieved clinical response, of whom 3 cases had endoscopic remission and 5 cases had endoscopic improvement respectively. Three (25%) patients suffered from pneumocystis carinii pneumonia, liver dysfunction and leukopenia, respectively, resulting in cessation of AZA in the initial 3 months. Four heterozygous missense variants of TPMT and NUDT15 were identified in four patients. One patient who had TPMT*6 and took AZA with the dose of 2.04 mg/kg per day suffered from severe leukopenia.

Conclusion: Azathioprine might be a good alternative medication in CCS patients who are steroid dependent or intolerant, or need augmentation therapy. The adverse events should be closely monitored especially myelosuppression and the tests of TPMT and NUDT15 genotypes before therapy may be helpful for medication guidance.