Weber Nicholas D, Odriozola Leticia, Ros-Gañán Irene, García-Porrero Guillermo, Salas David, Argemi Josepmaria, Combal Jean-Philippe, Kishimoto Takashi K, González-Aseguinolaza Gloria
Vivet Therapeutics S.L., Pamplona, Spain.
Division of Gene Therapy and Regulation of Gene Expression, Cima Universidad de Navarra, Pamplona, Spain.
JHEP Rep. 2023 Feb 24;5(5):100713. doi: 10.1016/j.jhepr.2023.100713. eCollection 2023 May.
BACKGROUND & AIMS: Gene therapy using recombinant adeno-associated virus (rAAV) vector carrying multidrug resistance protein 3 (MDR3) coding sequence (AAV8-MDR3) represents a potential curative treatment for progressive familial intrahepatic cholestasis type 3 (PFIC3), which presents in early childhood. However, patients with the severest form of PFIC3 should receive treatment early after detection to prevent irreversible hepatic fibrosis leading ultimately to liver transplantation or death. This represents a challenge for rAAV-based gene therapy because therapeutic efficacy is expected to wane as rAAV genomes are lost owing to hepatocyte division, and the formation of AAV-specific neutralising antibodies precludes re-administration. Here, we tested a strategy of vector re-administration in infant PFIC3 mice with careful evaluation of its oncogenicity - a particular concern surrounding rAAV treatment.
AAV8-MDR3 was re-administered to infant mice 2 weeks after a first dose co-administered with tolerogenic nanoparticles carrying rapamycin (ImmTOR) given at 2 weeks of age. Eight months later, long-term therapeutic efficacy and safety were assessed with special attention paid to the potential oncogenicity of rAAV treatment.
Co-administration with ImmTOR mitigated the formation of rAAV-specific neutralising antibodies and enabled an efficacious second administration of AAV8-MDR3, resulting in stable correction of the disease phenotype, including a restoration of bile phospholipid content and healthy liver function, as well as the prevention of liver fibrosis, hepatosplenomegaly, and gallstones. Furthermore, efficacious repeat rAAV administration prevented the appearance of liver malignancies in an animal model highly prone to developing hepatocellular carcinoma.
These outcomes provide strong evidence for rAAV redosing through co-administration with ImmTOR, as it resulted in a long-term therapeutic effect in a paediatric liver metabolic disorder, including the prevention of oncogenesis.
Redosing of gene therapy for inborn hepatobiliary disorders may be essential as effect wanes during hepatocyte division and renewal, particularly in paediatric patients, but the approach may carry long-term risks of liver cancer. Viral vectors carrying a therapeutic gene exerted a durable cure of progressive familial intrahepatic cholestasis type 3 in infant mice and reduced the risk of liver cancer only following a second administration.
使用携带多药耐药蛋白3（MDR3）编码序列的重组腺相关病毒（rAAV）载体（AAV8-MDR3）进行基因治疗，是治疗早发型进行性家族性肝内胆汁淤积症3型（PFIC3）的一种潜在的治愈性疗法。然而，最严重形式的PFIC3患者在确诊后应尽早接受治疗，以防止不可逆转的肝纤维化，最终导致肝移植或死亡。这对基于rAAV的基因治疗构成了挑战，因为随着rAAV基因组因肝细胞分裂而丢失，治疗效果预计会减弱，并且AAV特异性中和抗体的形成会妨碍再次给药。在此，我们在幼年PFIC3小鼠中测试了载体再次给药的策略，并仔细评估了其致癌性——这是rAAV治疗特别需要关注的问题。
在2周龄时首次给予携带雷帕霉素的耐受性纳米颗粒（ImmTOR）的同时给予一剂AAV8-MDR3，2周后对幼年小鼠再次给予AAV8-MDR3。八个月后，评估长期治疗效果和安全性，特别关注rAAV治疗的潜在致癌性。
与ImmTOR共同给药可减轻rAAV特异性中和抗体的形成，并能有效地再次给予AAV8-MDR3，从而稳定纠正疾病表型，包括恢复胆汁磷脂含量和健康的肝功能，以及预防肝纤维化、肝脾肿大和胆结石。此外，有效的重复rAAV给药可防止在极易发生肝细胞癌的动物模型中出现肝脏恶性肿瘤。
这些结果为通过与ImmTOR共同给药进行rAAV再次给药提供了有力证据，因为它在一种儿童肝脏代谢紊乱疾病中产生了长期治疗效果，包括预防肿瘤发生。
对于先天性肝胆疾病的基因治疗，由于在肝细胞分裂和更新过程中效果会减弱，再次给药可能至关重要，尤其是在儿科患者中，但这种方法可能存在肝癌的长期风险。携带治疗性基因的病毒载体在幼年小鼠中对进行性家族性肝内胆汁淤积症3型产生了持久的治愈效果，并且仅在第二次给药后降低了肝癌风险。
