Laboratory of Viral Immunopathology, Unit of Infectious Diseases and Hepatology, Azienda-Ospedaliero-Universitaria of Parma, Parma, Italy.
Division of Gastroenterology and Hepatology, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda, Ospedale Maggiore Policlinico, Università degli Studi di Milano, Italy.
Gastroenterology. 2018 May;154(6):1764-1777.e7. doi: 10.1053/j.gastro.2018.01.030. Epub 2018 Jan 31.
BACKGROUND & AIMS: The oral Toll-like receptor (TLR) 7 agonist GS-9620 has antiviral effects in woodchuck and chimpanzee models of chronic hepatitis B virus (HBV) infection. We investigated, in a clinical trial, the capacity of this agent to reconstitute protective immunity in patients with chronic HBV infection.
We performed a prospective study of 28 patients with suppression of HBV infection by nucleos(t)ide analogue therapy and who tested negative for hepatitis B e antigen at 4 medical centers in Italy. Patients were randomly assigned (1:3:3:3) to groups given placebo or different doses of GS-9620 (1, 2, and 4 mg, weekly for 12 weeks). We added data from 8 patients receiving nucleos(t)ide analogue therapy to the placebo group (controls); 13 treatment-naïve patients with chronic HBV infection and 15 subjects who spontaneously recovered from an acute HBV infection served as additional controls. Peripheral blood mononuclear cells were collected at baseline, during administration of GS-9620 or placebo, and 12 weeks afterward. Phenotype and function of natural killer (NK) and HBV-specific T cells were analyzed by flow cytometry. T cells were expanded by incubation with peptides from the entire HBV proteome and studied after overnight or 10 days culture. NK-cell inhibition of T-cell responses was measured by assessing cytokine production by T cells stimulated with peptides in the presence or absence of NK cells.
T cells collected at baseline before addition of GS-9620, when patients were receiving only nucleos(t)ide therapy, had greater responses to HBV than T cells from treatment-naïve patients, based on cytokine production in response to HBV peptides. However, during or after administration of GS-9620, T cells produced higher levels of cytokines compared to baseline. NK-cell activation and function increased after patients were given GS-9620, but the ability of NK cells to suppress T-cell responses was lower during GS-9620 therapy than before. Changes in T-cell or NK-cell function did not correlate with levels of hepatitis B surface antigen. Serum levels of hepatitis B surface antigen did not decrease significantly compared to baseline in patients given any dose of GS-9620.
Twelve weeks administration of GS-9620 had no significant effect on serum hepatitis B surface antigen levels, but did appear to increase T-cell and NK-cell responses and reduce the ability of NK to suppress T cells. GS-9620 might therefore be included in therapies to increase the immune response to HBV.
口服 Toll 样受体（TLR）7 激动剂 GS-9620 在土拨鼠和黑猩猩慢性乙型肝炎病毒（HBV）感染模型中具有抗病毒作用。我们在一项临床试验中研究了该药物在慢性 HBV 感染患者中重建保护性免疫的能力。
我们在意大利的 4 家医疗中心进行了一项前瞻性研究，纳入了 28 例接受核苷（酸）类似物治疗抑制 HBV 感染且乙型肝炎 e 抗原检测阴性的患者。患者随机（1:3:3:3）分为安慰剂组或不同剂量 GS-9620 组（1、2 和 4 mg，每周 12 周）。我们将接受核苷（酸）类似物治疗的 8 例患者的数据添加到安慰剂组（对照组）中；13 例慢性 HBV 感染的初治患者和 15 例急性 HBV 感染后自然康复的患者作为额外的对照组。在基线、接受 GS-9620 或安慰剂期间以及之后 12 周收集外周血单核细胞。通过流式细胞术分析自然杀伤（NK）和 HBV 特异性 T 细胞的表型和功能。通过孵育来自整个 HBV 蛋白质组的肽来扩增 T 细胞，并在过夜或 10 天后培养后进行研究。通过测量在存在或不存在 NK 细胞的情况下用肽刺激 T 细胞后 T 细胞产生细胞因子的情况来测量 NK 细胞对 T 细胞反应的抑制作用。
在加入 GS-9620 之前的基线时收集的 T 细胞，当患者仅接受核苷（酸）治疗时，对 HBV 的反应大于初治患者的 T 细胞，这是基于对 HBV 肽的细胞因子产生。然而，在给予 GS-9620 期间或之后，T 细胞产生的细胞因子水平高于基线。给予 GS-9620 后 NK 细胞的激活和功能增加，但在 GS-9620 治疗期间，NK 细胞抑制 T 细胞反应的能力低于治疗前。T 细胞或 NK 细胞功能的变化与乙型肝炎表面抗原水平无关。与基线相比，接受 GS-9620 治疗的患者的乙型肝炎表面抗原血清水平没有显著下降。
GS-9620 治疗 12 周对乙型肝炎表面抗原血清水平没有显著影响，但似乎确实增加了 T 细胞和 NK 细胞的反应，并降低了 NK 抑制 T 细胞的能力。因此，GS-9620 可能被纳入增加对 HBV 免疫反应的治疗中。
