Concurrent ipilimumab and CMV colitis refractory to oral steroids

Discussion

Diarrhea and colitis are common irAEs attributable to checkpoint-inhibitor therapy used for the treatment of melanoma. This case of ipilimumab-induced colitis refractory to high-dose oral steroids demonstrates the risks associated with management of anti-CTLA-4 induced colitis. In particular, the high-dose corticosteroids required to treat the autoimmune component of this patient’s colitis increased her susceptibility to CMV reactivation.

The diagnosis of colitis secondary to ipilimumab is made primarily in the appropriate clinical setting, and typically onsets during the induction period (within 12 weeks of initial dosing) and most resolve within 6-8 weeks.⁶ Histopathologically, there is lymphoplasmacytic expansion of lamina propria, increased intraepithelial lymphocytes, and increased epithelial apoptosis of crypts. One can also see acute cryptitis and crypt abscesses. Reactive epithelial changes with mucin depletion are also often seen in epithelial cells.

Findings from immunohistochemical studies have shown the increased intraepithelial lymphocytes to be predominantly CD8-positive T cells, while the lamina propria contains an increase in the mixture of CD4- and CD8-positive T cells. In addition, small intestinal samples show villous blunting. There is an absence of significant architectural distortion and well-developed basal lymphoplasmacytic infiltrates characteristic of chronic mucosal injury, such as idiopathic inflammatory bowel disease.⁷ Granulomas are also absent in most series, though they have been reported in some cases.⁸ The features are similar to those seen in autoimmune enteropathy, but goblet and endocrine cells remain preserved. Graft-versus-host disease has similar histologic features, however, the clinical setting usually makes the distinction between these obvious.

Current treatment algorithms for ipilimumab-related diarrhea, begin with immediate treatment with intravenous methylprednisolone (125 mg once). This is followed with oral prednisone at a dose of 1-2 mg/kg tapered over 4 to 8 weeks.⁴ In patients with persistent symptoms despite adequate doses of corticosteroids, infliximab (5 mg/kg every 2 weeks) is recommended until the resolution of symptoms, and a longer taper of prednisone is often necessary.

Institution of high-dose corticosteroids to treat grade 3 or 4 irAEs can increase the risk for infection, including opportunistic infections. One retrospective review of patients administered checkpoint inhibitors at a single institution revealed that 7.3% of 740 patients developed a severe infection that lead to hospitalization or treatment with intravenous antibiotics.⁹ In that patient cohort, only 0.6% had a serious infection secondary to a viral etiology, and 1 patient developed CMV enterocolitis. Most patients who developed an infection in this cohort had received corticosteroids (46/54 patients, 85%) and/or infliximab (13/54 patients, 24%).⁹

CMV is a member of the Herpesviridae family. After a primary infection, which can often go unrecognized in an immunocompetent host, CMV can persist in a latent state.¹⁰ In a study by Bate and colleagues, the age-adjusted seropositivity of CMV was found to be 50.4%.¹¹ Based on those results, immunosuppression in a patient who has previously been infected with CMV can lead to a risk of reactivation or even reinfection. In the era of checkpoint-inhibitor therapy, reactivation of CMV has been described previously in a case of CMV hepatitis and a report of CMV colitis.^12,13 Immunosuppression, such as that caused by corticosteroids, is a risk factor for CMV infection.¹⁴ Colitis caused by CMV usually presents with abdominal pain, diarrhea, and bloody diarrhea.¹⁵ In suspected cases of CMV colitis, endoscopy should be pursued with biopsy for tissue examination. A tissue diagnosis is required for CMV colitis because serum PCR can be negative in isolated cases of gastrointestinal CMV infection.¹⁵

Conclusion

Despite appropriate treatment with ganciclovir and the noted response in the patient’s serum CMV PCR, symptom exacerbation was observed with the transition to oral prednisone. The requirement for intravenous corticosteroids in the present case demonstrates the prolonged effects exerted by irAEs secondary to checkpoint-inhibitor therapy. Those effects are attributable to the design of the antibody – ipilimumab is a fully humanized monoclonal antibody and has a plasma half-life of about 15 days.^1,4

By the identification of CMV histopathologically, this case, along with the case presented by Lankes and colleagues,¹³ illustrates the importance of considering CMV colitis in patients who are being treated with ipilimumab and who develop persistent or worsening diarrhea after initial treatment with high-dose steroids.

Early recognition of possible coexistent CMV colitis in patients with a history of treatment with ipilimumab can have important clinical consequences. It can lead to quicker implementation of proper antiviral therapy and minimization of immune suppression to levels required to maintain control of the patient’s symptoms.