メラノーマに対するがんワクチンにおいて有望な結果が得られた （Abstract #: CRA9011）

転移性メラノーマ患者においてワクチンは奏効率を改善し無増悪生存期間を延長する
Vaccine improves response rate and extends progression-free survival in patients with metastatic melanoma
Phase III多施設トライアルの予備的所見によると、転移性メラノーマ患者において、gp100:209-217(210M)ペプチドと呼ばれる新たながんワクチンを標準治療に追加することにより、奏効率が倍になり無増悪生存期間が延長し、有意な副作用は認められなかったと第45回American Society of Clinical Oncology学会で発表された。このワクチンは投与されると、T細胞を刺激し増加させ、細胞表面のgp100抗原を発見することによりメラノーマ細胞を探し出し攻撃する。このスタディにおいて、ワクチンおよびインターロイキン－2（IL-2）投与群に無作為化割り付けされた患者86人とIL-2のみの投与群に割り付けられた患者93人における奏効率、無増悪生存期間、および全生存期間を比較した。ワクチン群において2倍以上の患者が治療に反応し腫瘍が縮小した（22.1%対9.7%、p=0.0223）。無増悪生存期間はワクチン群においてIL-2のみの群よりも長かった（2.9ヵ月対1.6ヵ月、p=0.0101）。研究者らはまた、標準治療に加えワクチン治療を受けた患者は標準治療のみを受けた患者よりも5ヵ月長く生存し（17.6ヵ月対 12.8ヵ月、p=0.0964）、全生存期間も延長する傾向が見られたことも報告した。
Full Text

Preliminary findings from a phase III, multicenter trial show that adding a novel cancer vaccine - called gp100:209-217(210M) peptide - to standard therapy doubles response rates and extends progression-free survival in patients with metastatic melanoma, without causing significant side effects.

"This study is one of the first to show positive, promising results for a cancer vaccine in melanoma" said lead author Douglas Schwartzentruber, M.D., medical director of the Center for Cancer Care at Goshen Health System in Indiana and clinical associate professor of surgery at Indiana University. "Metastatic melanoma is a very difficult disease to treat successfully and is very resistant to most therapies. These results will give patients and the oncology community hope that we are making some progress against this disease."

The vaccine is made from a peptide that is part of the gp100 protein - an antigen found on the surface of melanoma cells that acts as a marker for melanoma cells. When administered, the vaccine stimulates T cells to multiply and to seek and attack melanoma cells by locating this gp100 antigen. It was administered with interleukin-2 (IL-2), a standard therapy for advanced melanoma that boosts the immune response to the vaccine.

In this study, response rate, progression-free survival, and overall survival were compared between 86 patients who were randomly assigned to receive the vaccine plus IL-2, and 93 patients who received IL-2 alone. More than twice as many patients in the vaccine group responded to treatment with tumor shrinkage (22.1 percent versus 9.7 percent). Progression-free survival and overall survival were also longer in the vaccine group (2.9 months and 17.6 months, respectively) compared with the IL-2 only group (1.6 months and 12.8 months). Researchers reported a trend toward improved overall survival among patients who received it along with standard therapy, who lived nearly five months longer than those who received standard therapy alone.

The vaccine was well tolerated; swelling and redness at the injection site were the only side effects. The investigators are continuing to follow the patients to see how long the vaccine remains effective and to assess its value in various patient subgroups.