A NOVEL LIVER-DIRECTED LOCKED NUCLEIC
ACID TARGETING PD-L1 EXPRESSION REVERTS HBV-SPECIFIC
IMMUNE TOLERANCE AND INDUCES SUSTAINED CLEARANCE
OF HBV INFECTION
Jie Zhao1, Lykke Pedersen2, Julie Blaising3, Malika Ait-
Goughoulte3, Fang Shen1, Youjun Yu1, Johanna Walther3,
Anna-Maria Geretti3, Timothy Tellinghuisen3, John Young3,
Soren Ottosen2 and Souphalone Luangsay3, (1)Roche Pharma
Research and Early Development, Roche Innovation Center
Shanghai, Shanghai, China, (2)Roche Pharma Research and
Early Development, Roche Innovation Center Copenhagen,
Hørsholm, Denmark, (3)Roche Pharma Research and
Early Development, Roche Innovation Center Basel, Basel,
Switzerland
Background: Functional impairment of HBV-specific T cell
responses is the hallmark of chronic HBV infection. The
PD-1/ PD-L1 pathway is a key immune checkpoint regulator
responsible for delivering a strong immune-inhibitory signal
in the liver of chronic hepatitis B patients. We present a new
technology that uses a liver-targeted locked nucleic acid (LNA)
single stranded antisense oligonucleotide (ASO) to suppress
PD-L1 expression in hepatocytes (PD-L1 LNA) and disrupt the
PD-1/ PD-L1 pathway in the liver microenvironment, thereby
restoring local HBV-specific T cell effector function. Methods:
We generated a GalNAc-conjugated LNA ASO directed
against mouse PD-L1 and evaluated several subcutaneous
doses ranging from 3 to 15 mg/kg, once weekly (QW), in
the AAV-HBV mouse model. Circulating HBV parameters
(HBsAg, HBeAg, HBV DNA) were monitored weekly during
4 weeks of dosing and for 8 weeks after the end of dosing
Intrahepatic expression of PD-L1 mRNA (by RT-qPCR), HBVspecific
immune response (by IFN-γ Elispot) and liver-resident
and circulating immune cell subsets (by flow cytometry) were
evaluated in mouse liver at the end of the study Results:
Mice receiving 5 QW doses of PD-L1 LNA showed a marked
inhibition of PD-L1 mRNA expression at all tested doses (e g ,
~70% reduction after 2 doses at 5 mg/kg) Inhibition of PD-L1
expression was maintained (~50%) for at least 8 weeks postdosing,
and was associated with a significant and sustained
reduction of HBsAg, HBeAg and HBV DNA levels (2.4, 2.1 and
1 6 log10 drop, respectively), with no evidence of post-dosing
rebound After 2 to 5 doses, concomitant with the decline of
viral parameters, and depending on the dose, we observed a
transient serum ALT increase, without changes in markers of
liver function Interestingly, mice treated with PD-L1 LNA (5
QW doses at 5 mg/kg) showed a marked increase (2.8 fold)
in intrahepatic immune cell numbers, consisting of mainly
T cell subsets and antigen presenting cells, together with
a significant increase in HBV specific IFN-γ secreting cells
(~40 fold) compared to the vehicle control group Treatment
was well tolerated with no significant changes in body weight.
Conclusion: The findings support the hypothesis that a livertargeted
PD-L1 LNA ASO can result in effective suppression
of PD-L1 expression in the liver This new immunotherapy
offers the potential to overcome the immune tolerance that
characterises HBV infection, and achieve sustainable control
of viral replication. 作者: StephenW 时间: 2019-11-2 20:18