The PTLD-2 trial is the next step in the development of this strategy. Compared to the PTLD-1/3 trial, the key difference is the use of subcutaneous instead of intravenous rituximab application. Interim results from an ongoing trial of patients with follicular lymphoma (NCT01200758) have shown that subcutaneous administration results in increased blood levels and in non-inferior remission rates. Furthermore, the stratification strategy is refined based on observations from the previous PTLD-1 and PTLD1/3 trials: Risk groups are now defined not only based on response to rituximab therapy but also on the international prognostic index (IPI, a well-established lymphoma risk score) and the transplanted organ. The major advantage of this new stratification is an extended low-risk group that is eligible for subcutaneous rituximab monotherapy: Patients with a low risk of disease progression, defined as those who achieve a complete remission after the first four courses of subcutaneous rituximab monotherapy and those with an IPI of 0 to 2 who achieve a partial remission at interim staging, will go on with rituximab monotherapy. Patients with high IPI who achieve a partial remission, patients with stable disease at interim staging and non-thoracic transplant recipients with progressive disease at interim staging will be considered high risk. These patients will go on with 4 cycles of rituximab plus CHOP chemotherapy similar to the PTLD-1/3 protocol. Thoracic transplant recipients refractory to rituximab will be considered very high risk and will go on with rituximab subcutaneous plus alternating chemotherapy with CHOP and DHAOx.