肝がん治療においてtremelimumabは有望である

C型肝炎を原因とする進行肝細胞がんの患者を対象とした小規模スタディにおいてtremelimumab の臨床効果の兆しが示された
Tremelimumab shows signs of clinical activity in small study of patients with advanced hepatocellular carcinoma due to hepatitis C
Tremelimumab治療は12か月以上、C型慢性肝炎による進行肝細胞がん患者を安定化させたとのスタディ結果が2012年AACR学会で発表された。研究者らは15mg/kgのtremelimumabを90日ごとに約2サイクル静脈内投与された患者21人を評価した。腫瘍量は2人の患者において軽減し、11人においては疾患が1年以上安定化した。Intention-to-treat解析において、全生存期間中央値は7.5か月であり無増悪期間は6.4か月であった。治療に関連した有害事象は80%の患者において認められた:グレード3以上の有害事象は掻痒1件、紫斑1件およびトランスアミナーゼ上昇5件であった。血液内のC型肝炎ウイルスの減少も認められ、抗ウイルス免疫の客観的な強化も伴っていた。筆者らは、今回のような少人数の患者において明らかな臨床効果が見極められるのは珍しく、また抗ウイルス活性に関する情報もまた、非常に有望であると述べている。
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Tremelimumab treatment stabilized patients with advanced hepatocellular carcinoma due to chronic hepatitis C infection for more than 12 months, according to data presented at the AACR Annual Meeting 2012.

Researchers evaluated 21 patients treated with tremelimumab intravenously at a dose of 15 mg/kg every 90 days for about two cycles. Tumor burden was reduced for two patients, and disease stabilized for more than a year in 11 patients.

"The unique conditions [of hepatocellular carcinoma and hepatitis C infection] permitted us to monitor the antitumor effects and immune response to well-defined viral antigens, killing two birds with one stone," said lead researcher Ignacio Melero, M.D., Ph.D., a consultant in the department of oncology and a professor and senior investigator in El Centro de InvestigaciÓn Médica Aplicada at Universidad de Navarra in Pamplona, Spain.

In an intention-to-treat analysis, researchers observed a median overall survival of 7.5 months and time to progression of 6.4 months. They reported treatment-related adverse events among 80 percent of patients; grade 3 or higher adverse events included one case of pruritus, one case of purpura and five cases of elevated transaminases.

Melero and colleagues also observed a reduction of hepatitis C virus in the patients' blood, which was also accompanied with objective enhancements of antiviral immunity.

"The short series of patients already showing clinical activity offers clear signs for the need to extend these trials," Melero said. "It is unusual to spot clear signs of clinical activity with such a small number of patients, and the information on antiviral activity is also very promising."

Pfizer supported the study, and MedImmune has licensed tremelimumab. Melero is a consultant for Bristol-Myers Squibb.