Registry of the German CLL Study Group Long Term Follow-up of Patients With CLL, B-PLL, T-PLL, SLL,T or NK-LGL, HCL and Richter's Transformation

The most frequent primary endpoint in phase III trials of CLL is progression-free survival (PFS). However, the most important endpoint is overall survival (OS) which is usually a secondary endpoint in such trials. The outcome after progression is critical and responses to second and subsequent therapies may differ between the trial arms. Therefore it is essential to assess OS in addition to PFS. In addition, late toxicities, such as myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML), Epstein-Barr virus (EBV)-associated lymphoproliferative disease or Hodgkin's disease, late opportunistic infections and second malignancies, are increasingly seen and are likely to differ depending on the intensity of therapy. Moreover, meta-analysis of several phase III trials with long follow-periods are desirable. Similarly, valid analyses of biological disease characteristics in relation to outcome are depending on large collections of clinical data with mature follow-up.

The findings of the CLL8 study provide evidence that the addition of rituximab to chemotherapy with Fludarabine and Cyclophosphamide (FC) may prolong survival of patients with CLL. However, it also opens the question about whether applying such therapy might cause certain late toxicities and whether it improves longterm survival for patients with CLL. Moreover the outcome of subsequent therapies after various first line treatments with Fludarabine (F), FC, Bendamustine and Rituximab (BR) or Fludarabine, Cyclophosphamide and Rituximab (FCR) amongst others outside of clinical trials needs to be investigated further.

Recently published phase III trials in CLL showed median observation times ranging from 22 to 41 months, but most of the trials report observation times around 2 years only. For most of the phase III trials of the German CLL Study Group (GCLLSG) great efforts were made to implement an extended follow up in these trials, but due to administrative reasons the follow up is limited to at most 8 years. This registry should enable the collection of data of the entire course of diseases in- and outside of clinical trials.

Besides CLL other related rare lymphoproliferative malignancies will be included in this registry. On the one hand for historical on the other hand for clinical reasons these diseases are close to CLL and information about them should be gathered as best as possible.

Only limited information is available for patients with SLL, B-PLL, T-PLL, T/NK-LGL, HCL and Richter's transformation. They carry orphan disease status and long-term follow-up data is urgently needed.