除菌無効胃MALTリンパ腫とrituximab抗体療法

Clinical Findings of Gastric MALT Lymphoma Not Eligible for Helicobacter pylori, Eradication with Rituximab as Second-line Treatment

要旨　胃MALTリンパ腫で除菌無効となる要因は，H. pylori陰性，高悪性度成分の混在，API2-MALT1融合遺伝子が陽性であることが挙げられる．89例におけるH. pylori陽性率は94.4％で，陽性例に対する除菌奏効率は81.9％である．除菌無効例のうち10例はrituximab抗体療法を二次治療として希望された．平均年齢は58.9歳で，部位は噴門部1例，胃体部8例，前庭部1例で，除菌前の肉眼型は隆起型1例，潰瘍型3例，表層型6例であった．抗体療法までの期間は除菌後平均21.0か月（4.5～53.4か月）で，1年以上2年未満が7例と多い．抗体療法は10例全例に奏効し，7例は褪色瘢痕化し3例は瘢痕も不明瞭となった．寛解期間は平均26.9か月，最長38.6か月で，現在まで再発はない．またH. pylori陰性例では抗体療法を希望した5例中4例（80％）で奏効している．

　The goals of the current study were to elucidate the long-term outcome of Helicobacter pylori (H. pylori) eradication therapy for gastric MALT (mucosa-associated lymphoid tissue) lymphoma and to clarify the therapeutic efficacy of stomach-conserving treatments for patients not responding to eradication therapy.

　H. pylori eradication therapy leads to complete remission (CR) in 81.9％ (68/83) of early stage gastric MALT lymphoma. H. pylori eradication therapy was an effective first-line treatment for gastric MALT lymphoma, which led to a favorable long-term outcome. The treatment for H. pylori-negative gastric MALT lymphoma has not been advancing.

　Ten patients not responding to eradication therapy underwent rituximab treatments. Rituximab is a chimeric anti-CD20 antibody. As a second-line treatment, 375mg/m² of rituximab weekly achieved CR in 10 patients.

　Monoclonal antibody rituximab had an equivalent efficacy as a second-line treatment in nonresponding patients to eradication therapy and H. pylori negative patients.