A Study of the Bruton's Tyrosine Kinase (BTK) Inhibitor Ibrutinib in Participants With Steroid Dependent/Refractory Chronic Graft Versus Host Disease (cGVHD)

Inclusion Criteria:

• Steroid dependent/refractory chronic graft versus host disease (cGVHD) defined as modified National Institutes of Health (NIH) criteria (2014) below at any time post-hematopoietic cell transplant (post-HCT): a) Dependent disease, defined as, when glucocorticoid (prednisolone doses greater than or equal to [>=] 0.25 milligram per kilogram per day (mg/kg/day)or >=0.5 milligram per kilogram (mg/kg) every other day) are needed to prevent recurrence or progression of manifestations as demonstrated by unsuccessful attempts to taper the dose to lower levels on at least 2 occasions, separated by at least 8 weeks. In case of inability to taper the dose to less than or equal to (<=)0.25 mg/kg/day or <=0.5 mg/kg every other day (prednisolone doses) due to recurrence or progression of cGVHD manifestations, it is considered as steroid-dependent disease if the lowest tapering dose of the second occasion is equal or higher than the lowest tapering dose of the first occasion; b) Refractory disease, defined as, when cGVHD manifestations progress despite the use of a regimen containing glucocorticoid (prednisolone at >=1 mg/kg/day for at least 1 week) or persist without improvement despite continued treatment with glucocorticoid (prednisolone at >=0.5 mg/kg/day or 1 mg/kg every other day) for at least 4 weeks
• Participants must be receiving baseline systemic glucocorticoid therapy for cGVHD at study entry. The dose of steroids must be stable for 14 days prior to starting ibrutinib
• At the time of trial enrollment, participants may be receiving other immunosuppressive therapies in addition to glucocorticoids. Immunosuppressant doses must be stable for 14 days prior to starting ibrutinib
• Clinically stable or worsening cGVHD for a minimum of 14 days between screening and Day 1 cGVHD response assessment
• Karnofsky or Lansky (participants less than [<]16 years) performance status >=60

Exclusion Criteria:

• Active acute graft versus host disease (GVHD)
• More than 3 previous systemic treatments for cGVHD. Treatment with glucocorticoids is considered a treatment for cGVHD and should be included in determining the number of previous treatments
• History of treatment with a tyrosine kinase inhibitor (example [e.g.] imatinib), purine analogs, or other cancer chemotherapy in the 4 weeks prior to starting ibrutinib. Participants may have received ibrutinib pre-transplant for other reasons besides cGVHD such as for the treatment of leukemia or lymphoma
• History of treatment with monoclonal T and B cell antibodies in the 8 weeks prior to starting ibrutinib
• Vaccinated with live, attenuated vaccines within 4 weeks of first dose of ibrutinib