Cancer Killers


By Avery D. Posey, Jr. /Carl H. June/Bruce L. Levine A. D. ポージー /C. H. ジューン/B. L. レバイン
English 日本語 日本語
Tumor immunologists have known for decades that the immune system can be an important ally in the fight against cancer. Most early attempts to recruit its potential proved disappointing, however. It turns out that investigators had not done enough to stimulate a key component of the immune system, a kind of master sergeant called the T cell. Without enhancing the ability of T cells both to identify and to attack cancer cells, researchers were, in effect, asking the immune system to go into battle with the biological equivalent of paper airplanes and pellet guns.  がんとの闘いで免疫系が重要な味方になりうることを,腫瘍免疫学者は何十年も前から知っていた。しかし,その潜在能力を引き出そうとした初期の試みはほとんどが期待外れに終わった。免疫系のカギを握る「T細胞」という指揮官のような細胞を十分に活性化できなかったのだ。がん細胞を見つけて攻撃するT細胞の能力を強化できなければ,免疫系に紙飛行機とオモチャの銃で闘えと言っているようなものだ。
The first clues that T cells needed to be greatly fortified to fight cancer emerged in the 1980s. Researchers tried to strengthen the immune responses by drawing T cells from patients, multiplying them in the laboratory and then infusing the expanded number of cells back into the body. That approach helped some people but typically did not work for long: the cells tended to exhaust themselves and shut down soon after delivery.  がんと闘うためT細胞を大幅に強化する必要があることが最初に示唆されたのは1980年代だった。研究者は患者からT細胞を取り出して実験室で大量に増やし,身体に戻すことで免疫応答を増強しようとした。この方法は一部の患者には有効だったが,ほとんどの場合,長くは効かなかった。細胞は導入後すぐに力を使い果たし,働かなくなることが多かった。
Various groups of investigators then began addressing the problem in different ways. One strategy that we and our colleagues have developed is now showing exciting promise in clinical trials. Back in the mid 1990s, while trying to discover new treatments for HIV, two of us (June and Levine) created an improved technique to turbocharge T cells drawn from patients, making the cells more abundant, powerful and longer-acting than previous methods could achieve. Then, about a decade ago, a new way of genetically altering T cells became available that would allow them to efficiently home in on and attack certain kinds of cancer—such as leukemia and lymphoma—that originate in various types of white blood cells.  その後,様々な研究グループがいろいろな方向からこの問題の解決に乗り出した。そして今,私たちが開発したある戦略が,臨床試験で素晴らしく有望な結果を出している。
In the past few years these synthetic immune cells, known as chimeric antigen receptor T—or CAR T—cells, have been tested in dozens of studies collectively involving close to 1,000 patients with advanced cases of leukemia or lymphoma. Depending on the disease, half or more of those patients are now living longer than expected, and hundreds appear to be cancer free.  この数年間で,これら「キメラ抗原受容体発現T(CAR-T)細胞」と呼ばれる組み換え細胞は進行した白血病や進行したリンパ腫を対象に数十件の臨床試験が行われており,総計1000人近い患者が参加している。がんの種類にもよるが,患者のうち半数以上が予想より長く生存しており,がんが消えたとみられる患者も数百人いる。
A consensus is building among cancer researchers that treatment with CAR T cells—either alone or in combination with other therapies—will eventually provide durable cures for certain blood cancers. The next hurdles will include confirming if this type of therapy can be effective against other kinds of tumors and better controlling the side effects, some of which can be fatal. But the success so far, which involved tackling a series of difficult challenges over the course of about 20 years, is heartening.  がん研究者の間では,CAR-T細胞療法(単独もしくは他の治療法との併用)はいずれ特定の血液がんの恒久的治療法になるという見方が共通認識となりつつある。次の課題は,このタイプの治療法が他のがんにも有効かどうかを確かめることと,命にかかわる場合もある副作用を軽減することだろう。こうした課題はあるが,過去約20年にわたり数々の困難を乗り越えて有望な成果を得てきたことは心強い。