新たな化学療法剤は転移性乳がんの生存率を改善する

EMBRACEトライアル：海綿由来の新薬eribulinは転移性乳がん患者の生存率を改善する
EMBRACE Trial: New agent, eribulin, derived from marine sponge, increases survival among women with metastatic breast cancer
2010年ASCOで発表されたphase III無作為化トライアルの結果から、新たな化学療法薬eribulin mesylateは、既に従来の治療で強力に治療された局所再発性または転移性乳がん患者の全生存期間を2.5ヵ月延長させたことが示された。Eribulin mesylateは、細胞分裂に影響する新しいタイプの“微小管ダイナミクス阻害薬”である；この薬剤は海綿由来である。このEMBRACEと呼ばれる国際多施設トライアルは、平均4回のアントラサイクリン系やタキサン系の化学療法を既に受けた局所再発性または転移性乳がんを有する女性に対し、eribulin mesylateを“医師の選択による治療”と比較した初めてのトライアルである。これらの患者においては単剤の化学療法は標準的ではないため医師らはコントロール群の患者に対し現実的な選択を反映するような治療を選択した。転移性乳がんの女性をeribulin（508人）または医師らの選択した治療法（ほとんどそれぞれ異なる化学療法；254人）を受ける群に無作為に割り付けた。その結果、生存期間中央値はeribulin群において有意に長かった（13.1ヵ月対10.7ヵ月）。このスタディの二次エンドポイント（無増悪生存期間および奏効率）もまたeribulin群において良好であり、忍容性も全般的に良好であった。
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A Phase III randomized trial finds that a new chemotherapy agent, eribulin mesylate, extends median overall survival by about 2.5 months among women with locally recurrent or metastatic breast cancer who had already been heavily treated with conventional therapies.

"Until now, there hasn't been a standard treatment for women with such advanced breast cancer. For those who have already received all of the recognized treatments, these are promising results," said lead author Christopher Twelves, M.D., professor of clinical cancer pharmacology and oncology, and Head of the Clinical Cancer Research Groups at the Leeds Institute of Molecular Medicine and St. James's Institute of Oncology in Leeds, U.K. "These findings may establish eribulin as a new, effective option for women with heavily pre-treated metastatic breast cancer."

Eribulin mesylate is a new type of "microtubule dynamics inhibitor" that affects cell division; the drug is derived from a marine sponge. The international, multicenter trial, called EMBRACE, is the first to compare eribulin mesylate to "treatment of physician's choice" in women with locally recurrent or metastatic breast cancer who had already received an average of four prior chemotherapy drugs, such as anthracyclines or taxanes. Because no single chemotherapy regimen is standard for these women, physicians chose which treatment to give patients in this study's control arm, to reflect real-life choices.

Dr. Twelves and his colleagues compared overall survival among 762 patients with metastatic breast cancer who were randomized to receive either eribulin (508 women) or their physician's choice of therapy (254 women), which was almost always another chemotherapy. The median survival for the eribulin group was significantly longer: 13.1 months versus 10.7 months. The study's secondary endpoints (progression-free survival and objective response rate) also favored eribulin, which was generally well tolerated.

Disclosures: Christopher Twelves, Consultant or Advisory Role, Eisai, Expert Testimony, Eisai; Joanne Blum, Consultant or Advisory Role, Eisai; Linda Vahdat, Consultant or Advisory Role, BMSO, Eisai, Research Funding, BMSO, Eisai, Research Funding, ImClone Systems; Corina Akerele, Employment/Leadership Position, Eisai; Seth Seegobin, Employment/Leadership Position, Eisai; Jantien Wanders, Employment/Leadership Position, Eisai; Javier Cortes, Consultant or Advisory Role, Eisai.

This abstract was presented or published pursuant to an exception to the ASCO Conflict of Interest Policy.