A phase II study of intratumoral administration of the autologous immature dendritic cell (DC) vaccine used after lesion photodynamic therapy (PhDT) and immunomodulation with cyclophosphamide (Cy) in pretreated patients with disseminated malignant melanoma.

Abstract

3088 Background: Immature DC can be loaded in vivo with tumor-specific antigens after tissue destruction and induce specific immune response even in pretreated patients with unfavorable prognosis. We assess clinical efficacy of this approach in melanoma patients after at least 1 line of drug therapy in metastatic setting. Methods: Totally, 14 pts were enrolled: 11 men, 3 women. Stage M1a in 4 (28%) pts, M1b in 1 (7%) and M1c was in 9 (64%) pts. Patient received Cy 300 mg IM at D0, photoditasine (PH) at D3, PhDT therapy on injectable lesion 2 hrs after PH (662 nm, 300 J). The immature DC derived from peripheral blood stem-cells were injected in irradiated lesion 6 hrs after photodynamic therapy at D3 and daily until D7 of the 21-day cycle. Vaccine dose was 60-100*10^6 cells. Toxicity was measured by CTC AE v4, efficacy by RECIST 1.0. Primary endpoint was clinical benefit rate (CBR), secondary – overall survival (OS), response rate (RR), time to progression (TTP) and toxicity. Results: 14 pts were evaluable for toxicity, 13 for response. 37 cycles of therapy were performed. 2 patients achieved PR lasting 393 and 218+ days. 5 patients were stable for 33+, 108, 113, 168 and 239 days. RR was 15 (95% CI 2-39)%, CBR – 54 (95% CI 27-81)%. Median OS was 334 days, TTP – 113 days. RR was well correlated with OS (p=0,014). No SAE or AE of 4th degree occurred. The only grade 3 toxicity was fever. All grade 1-2 AEs were immune-related: fever (the most frequent AE), pain in the lesions, flu-like reactions, myalgia as well as high serum ALT, AST and bilirubin in patients with liver metastases. Conclusions: Thus, using the described approach for immunotherapy of melanoma has clinical efficacy and worth further developing.