HER2陽性進行胃・食道接合部腺がんに対するエボルパセプト+トラスツズマブ+ラムシルマブ+パクリタキセル併用療法が有効な可能性

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2026-09-30 国立がん研究センター

国立がん研究センターなどの国際研究チームは、HER2陽性で切除不能または転移性の胃・食道接合部腺がんを対象に、CD47阻害薬エボルパセプトをトラスツズマブ、ラムシルマブ、パクリタキセルに追加する治療の有効性・安全性を第II相無作為化試験で検討した。127例を対象とした結果、奏効割合はエボルパセプト併用群40.3%、対照群26.6%で、新規生検でHER2陽性が確認された患者では54.8%対23.1%だった。一方、事前設定された30%の閾値を統計学的に有意に上回るという主要評価項目は満たさなかった。探索的解析では、HER2発現が維持され、CD47を高発現する患者で奏効割合63.6%、無増悪生存期間中央値19.5か月と、より大きな治療効果が示された。CD47低発現例やHER2保持が確認されない例では明らかな上乗せ効果は認められなかった。結果は、CD47阻害とバイオマーカーによる患者選択を組み合わせた個別化治療の可能性を示している。安全性は既存治療と概ね同様だった。

HER2陽性進行胃・食道接合部腺がんに対するエボルパセプト+トラスツズマブ+ラムシルマブ+パクリタキセル併用療法が有効な可能性
図1A. エボルパセプト、トラスツズマブ、ラムシルマブ、パクリタキセル併用療法による抗腫瘍効果

<関連情報>

HER2陽性胃癌におけるエボルパセプト+トラスツズマブ、ラムシルマブ、パクリタキセル併用療法:ランダム化第2相試験 Evorpacept plus trastuzumab, ramucirumab and paclitaxel in HER2-positive gastric cancer: a randomized phase 2 trial

Kohei Shitara, Zev Wainberg, Josep Tabernero, Eric Van Cutsem, Clélia Coutzac, Christelle De La Fouchardière, Jeeyun Lee, Sun Young Rha, Yoon-Koo Kang, Philip Fanning, Alison Forgie, Cherry Mao, Daniel Brickman, Jaume Pons, Athanasios C. Tsiatis, Sophia Randolph & Keun-Wook Lee
Nature Medicine  Published:24 September 2026
DOI:https://doi.org/10.1038/s41591-026-04700-3

Abstract

Evorpacept blocks the CD47–signal regulatory protein α interaction, enhancing antibody-dependent cellular phagocytosis. In the phase 2 portion of ASPEN-06 (a multicenter, open-label, randomized phase 2/3 study), 127 patients with pretreated, human epidermal growth factor receptor 2 (HER2)-overexpressing, advanced gastric/gastroesophageal junction cancer were randomized to evorpacept plus trastuzumab, ramucirumab and paclitaxel (evo + TRP; n = 63; fresh HER2+ biopsy, n = 22) or TRP alone (n = 64; fresh HER2+ biopsy, n = 26). The primary end point was investigator-assessed objective response rate (ORR). The primary analysis of ORR was designed to evaluate an ORR exceeding the historical 30% benchmark (ramucirumab/paclitaxel) (80% power for intent to treat (ITT) and 50% power for the ITT subpopulation (HER2 overexpression based on a post-trastuzumab ‘fresh’ biopsy)) and an improvement of ≥8.0% and ≥9.7% versus TRP in the ITT and ITT subpopulations, respectively. Key secondary end points included ORR by blinded independent central review, duration of response and progression-free survival by investigator or blinded independent central review, overall survival and safety. Post hoc biomarker analyses, including the assessment of the association of treatment efficacy with retained HER2 status (defined by HER2 positivity on fresh tumor biopsy or amplification in circulating tumor DNA analysis) and CD47 expression in tumor samples, were conducted. The investigator-assessed ORRs were 40.3% (evo + TRP) versus 26.6% (TRP) in the ITT population and 54.8% versus 23.1% in the fresh biopsy HER2+ subgroup. ORR differences (13.7% and 31.7%) exceeded the prespecified thresholds in both the ITT population and fresh biopsy HER2+ subgroup, meeting one of the two primary objectives; however, compared to the historical benchmark (30%), ORRs in the ITT population (40.3%; P = 0.0949, one-sided) and fresh biopsy HER2+ subgroup (54.8%; P = 0.030, one-sided) did not meet the prespecified statistical criterion (one-sided α = 0.025). While hematologic toxicities were more common with evo + TRP, overall safety was similar. In summary, evo + TRP showed encouraging efficacy with manageable safety in advanced gastric/gastroesophageal junction cancer. ClinicalTrials.gov identifier: NCT05002127.

医療・健康
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