The purpose of this study is to evaluate the efficacy of Calcipotriene cream. This is a synthetic vitamin D3 derivative for topical use. It is used to treat grade 1-3 acute skin graft versus host disease (GVHD) in hematopoietic stem cell transplant (HSCT) recipients. Calcipotriene will be used as the exclusive topical therapy in addition to standard of care GVHD treatment prescribed for the study subject by the primary physician.

Acute skin GVHD affects about one third of pediatric and adult transplant recipients. Chronic GVHD (cGVHD) affects 40-60% of adult patients who have undergone allogeneic HSCT. It is a major cause of non-relapse mortality and morbidity. Systemic prednisone is the first-line treatment for cGVHD; however, about one-half of all patients do not respond to this initial therapy, and there is no standard second-line therapy. Immunosuppressive therapy used for treatment of GVHD brings significant risk of infection, poorly affecting clinical outcomes.

Vitamin D affects immunoregulation, fibroblast proliferation, collagen synthesis and endothelial cell function, and the investigators hypothesize that topical vitamin D application will have a positive effect on acute and chronic skin GVHD. The investigators hypothesize that topical vitamin D cream may restore normal cell function and decrease the use of steroid creams in acute GVHD of the skin.

Inclusion Criteria:

• HSCT recipients with acute Grade I through III GVHD based on Glucksberg criteria. Recipients of multiple transplants are still eligible to participate in this research study.
• Each study subject is to have calcium and vitamin D level prior to starting study, if not obtained within 30 days of beginning treatment.

Exclusion Criteria:

• Patient with active cellulitis at the start of the treatment.
• Patients with hypercalcemia or vitamin D levels above 100 μg/L.
• Patients with known allergy to any of the topical therapy components.
• Patients who have received previous treatment with topical vitamin D cream.