Matched-pair analysis of dendritic cell versus targeted-therapy in patients with metastatic renal cell carcinoma

Although targeted-therapy (TT) for patients with metastatic renal cell cancer (mRCC) has shown an improved outcome, their prognosis is still very poor. Immunotherapy with dendritic cells (DC) as one promising new treatment tries to fight cancer by boosting the patient's own immune system. The present analysis matches two different methods of treatment against mRCC, namely sequential TT versus DC vaccine therapy, by comparison of long-term overall survival (OS).

Data of patients treated with DC vaccines (N=30) in three clinical phase I/II trials (1999-2003) and patients treated with clinical standard targeted-therapy (N=30) at the University Hospital of Bonn (2010-2013) were analyzed regarding their OS, as well as specific characteristics such as number and localization of metastatic sites.

The mean OS from the first treatment was significantly higher in the TT than in the DC group (48 versus 21 months, range=3-85 months versus 1-57 months, respectively; p=0.0002). Patients with one (p=0.036) or two metastases (p=0.037) and especially patients with bone metastases (52 versus 12 months; p<0.0001) benefited significantly from TT. However, there was no significant difference between therapy types in patients with lung (p=0.147) or liver (p=0.745) metastases, or in patients with more than two metastatic sites (p=0.074).

Targeted therapy is an effective treatment against mRCC, but is limited due to common adverse events and a higher toxicity when combinations of different-targeted agents are used. Immunotherapy with DC vaccines seems to be a potent and well-tolerated therapy against mRCC, possibly showing higher benefit for patients with specific sites of metastasis, and should be investigated as a co-treatment with TT in further studies.