An Open Label Evaluation of the Safety and Pharmacokinetics of Ganciclovir in Children

Inclusion Criteria Concurrent Medication: Allowed: * Topical acyclovir. * Consult with the Syntex study monitor for the following: * Cytokines. * Soluble CD4. * Trichosanthin (Compound Q). * Imipenem-cilastatin. * Other investigational drugs. Patients must have the following: * Congenital or acquired immune deficiency. * Eligibility to receive ganciclovir for the treatment of life- or sight-threatening Cytomegalovirus (CMV) disease. Exclusion Criteria Co-existing Condition: Patients with the following conditions or symptoms are excluded: * Mild to moderate Cytomegalovirus infection that does not satisfy the clinical severity criteria. * Congenital or neonatal CMV infections without documented congenital or acquired immunodeficiency. Concurrent Medication: Excluded: * Other myelosuppressive drugs. * Antimetabolites. * Alkylating agents. * Nucleoside analogs (topical acyclovir is allowed). * Interferons. * Foscarnet. * Consult with the Syntex study monitor for the following: * Cytokines. * Soluble CD4. * Trichosanthin (Compound Q). * Imipenem-cilastatin. * Other investigational drugs. Patients with the following are excluded: * Mild to moderate Cytomegalovirus (CMV) infection that does not meet the clinical severity criteria. * Absolute neutrophil count (ANC) \< 500 cells/mm3 or a platelet count \< 25000 platelets/mm3. Note: * Exceptions may be made for patients with pre-existing neutropenia or thrombocytopenia and immediately life-threatening disease, if the investigator believes that a delay in starting ganciclovir therapy is not advisable. In such patients, the investigator should advise the parents or guardians of the risk of further bone marrow suppression and the increased risk of infection or bleeding. * Receiving excluded medications that it is not possible to discontinue. * Congenital or neonatal CMV infections without documented congenital or acquired immunodeficiency. * Demonstrated hypersensitivity to acyclovir or ganciclovir.