Defining ctDNA Metrics in Posttransplant Lymphoproliferative Disorder (PTLD)

Rituximab is a genetically engineered chimeric murine/human monoclonal IgG1 kappa antibody directed against the CD20 antigen. The Fab domain of rituximab binds to the CD20 antigen on B lymphocytes, and the Fc domain recruits immune effector functions to mediate B cell lysis. 375 mg/m2 Rituximab will be administered to participants by IV.

Etoposide is a topoisomerase II inhibitor and appears to cause DNA strand breaks. It has been shown to delay transit of cells through S phase and arrest cells in late S or early G2 phase. 50 mg/m2 Etoposide will be administered to participants by IV.

Prednisone can prevent or suppress inflammation and immune responses. Prednisone's action may include the inhibition of leukocyte infiltration at the site of inflammation, interference in the function of mediators of inflammatory response, and suppression of humoral immune responses. 60 mg/m2 Prednisone will be administered to participants by PO.

Vincristine is a vinca alkaloid. The mechanism of action of vincristine is thought to be due to inhibition of microtubule formation in the mitotic spindle. This leads to arrest of dividing cells during the metaphase stage. 0.4 mg/m2 Vincristine will be administered to participants by IV.

The mechanism of action is thought to involve cross-linking of tumor cell DNA. Cyclophosphamide is biotransformed principally in the liver to active alkylating metabolites which are thought to cross-link to tumor cell DNA. These metabolites interfere with the growth of rapidly proliferating susceptible malignant cells. 375 mg/m2 Cyclophosphamide will be administered to participants by IV.

Doxorubicin is an anthracycline, topoisomerase II inhibitor. It is isolated from cultures of Streptomyces peucetius var. caesius. The cytotoxic effect of doxorubicin is related to nucleotide base intercalation and cell membrane lipid binding activities. It blocks nucleotide replication and the action of DNA and RNA polymerases. The interaction between doxorubicin and topoisomerase II to form DNA-cleavable complexes appears to be an important mechanism of its cytocidal activity. 10 mg/m2 Doxorubicin will be administered to participants by IV.

Next generation sequencing (NGS) tool used to detect tiny amounts of cancer DNA in the blood, allowing for early diagnosis and monitoring of cancer in a non-invasive way.