Chemoimmunotherapy is the standard of care in first-line treatment of CLL patients without del17p or TP 53 mutation; physically fit patients are treated with fludarabine, cyclophosphamide and rituximab (FCR)1. Due to the high risk of severe neutropenias and infections with FCR, bendamustine and rituximab (BR) must be considered in patients aged >65 years.~However, these conventional chemoimmunotherapies are associated with side effects caused by the rather unspecific mode of action of the chemotherapy. Therefore, there is an urgent need for alternatives, especially chemotherapy-free regimens.~In first line treatment of elderly patients with CLL and coexisting conditions, the anti-CD20-antibody obinutuzumab is the new standard therapy. In the CLL11 trial the combination of obinutuzumab with chlorambucil proved to be safe and lead to markedly improved response rates as well as PFS times in comparison to chlorambucil alone or combined with rituximab.~The BCL2 antagonist venetoclax (GDC-0199/ABT-199) showed striking activity with tumor lysis syndrome as dose limiting toxicity in patients with relapsed and refractory CLL. 400 mg venetoclax was determined to be a safe and efficacious dose. Several patients treated with the combination of venetoclax and rituximab in relapsed refractory CLL even achieved MRD negativity. The FDA approved Venetoclax for the treatment of relapsed CLL with 17p/TP53 on 12th April 2016.~Therefore, venetoclax plus CD20-antibody based combinations have the potential to induce higher rates of MRD negativity in frontline therapy of CLL and concomitantly induce lower rates of toxicities so that chemotherapy might be replaced. Furthermore, venetoclax and obinutuzumab demonstrated synergistic activity in a preclinical study of a murine Non-Hodgkin lymphoma xenograft model, and additive activity in a CLL lymph node model. The combination appears tolerable in the firstline treatment of CLL patients with coexisting conditions whilst the toxicity profile of both drugs compares favorably to those of the chemotherapies currently used in the treatment of CLL. Consequently, it should be tested if rituximab can be replaced by obinutuzumab in combination with venetoclax in this trial.~Ibrutinib, a selective, irreversible small molecular inhibitor of Bruton´s Tyrosine Kinase (BTK), showed excellent responses and a safe toxicity profile9,10, even in combination with BR. Ibrutinib is approved for treatment of relapsed CLL as well as frontline therapy of CLL by the FDA and EMA (April 29th 2016).~The combination of ibrutinib and venetoclax showed synergy in primary CLL cells.~Consequently, the aim of the current trial is to evaluate if chemoimmunotherapy in the frontline treatment of physically fit patients in CLL can be replaced by combinations of these targeted drugs with anti-CD20-antibodies.
The aim of this study is to evaluate if standard chemoimmunotherapy (FCR, BR) in frontline treatment of physically fit CLL patients without del17p or TP 53 mutation can be replaced by combinations of targeted drugs (Venetoclax, Ibrutinib) with anti-CD20-antibodies (Rituximab, Obinutuzumab), which may induce extremely long lasting remissions.