Researchers involved in an international multicenter clinical Phase II trial have reported a 26% response rate for patients with metastatic melanoma treated with a second-generation granulocyte-macrophage colony-stimulating factor (GM-CSF) oncolytic herpes simplex virus (HSV) vaccine. The details of this study were published in the December 1, 2009 issue of the Journal of Clinical Oncology.[1]
Melanoma is considered an immune responsive cancer. A small fraction of patients with metastatic disease respond to a variety of immune therapies including: Proleukin® (interleukin-2), lymphokine activated killer (LAK) cells, tumor infiltrating lymphocytes (TIL), and genetically manipulated T-cells. In addition, there have been many attempts to develop a successful vaccine.
A previous Phase I study of this second-generation oncolytic HSV expressing GM-CSF was carried out in patients with a variety of solid tumors. In this study the vaccine was called OncoVEX-GM-CSF and is made by BioVex.[2] This study established a safe dose, and responses were observed in patients with melanoma and other solid tumors.
The current study evaluated the same vaccine, which is called JS1/34.5/47-/GM-CSF, for the treatment of 50 patients with metastatic melanoma. Seventy-five percent of patients in this study had failed one or more systemic therapies. Vaccine was injected into tumor nodules every two weeks for up to 24 treatments, and some patients who responded or were stable were then treated on an extended protocol. These authors made the following observations:
The overall response rate was 26%.
Eight patients (16%) had a complete response.
Five patients (10%) had a partial response.
Responses occurred in injected and distant sites.
10 patients (20%) had stable disease for more than three months.
92% of responses were maintained for 7-31 months.
Two additional patients had a complete response after surgery.
Two additional patients with an initial partial response or stable disease achieved a complete response after 24 months of further vaccination.
Overall survival at one year was 58% and 52% at two years.
Comments: These are the best results achieved to date for any vaccine for melanoma. This study will by followed up by a Phase III study to confirm these results.
References:
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[1] Senzer JJ, Kaufman HL, Amatruda T, et al. Phase II clinical trial of a granulocyte-macrophage colony-stimulating factor-encoding, second-generation oncolytic herpesvirus in patients with unresectable metastatic melanoma. Journal of Clinical Oncology. 2009;27:5763-5771.
[2] Hu JC, Coffin RS, Davis CJ, et al: A phase I study of OncoVEXGM-CSF, a second-generation oncolytic herpes simplex virus expressing granulocyte macrophage colony-stimulating factor. Clin Cancer Res. 12:6737–6747, 2006.
Source:http://professional.cancerconsultants.com/oncology_main_news.aspx?id=44340
Take Care,
Jimmy B
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