Market Overview

Arcus Biosciences Announces Initiation of Phase 1 Trial for AB154, its Anti-TIGIT Antibody


Arcus Biosciences, Inc. (NYSE:RCUS), a clinical-stage biopharmaceutical
company focused on creating innovative cancer immunotherapies, today
announced that it has received regulatory approval to initiate its Phase
1 trial for AB154, its anti-TIGIT antibody, and expects to start dosing
patients shortly. AB154 is the Company's third product candidate to
enter clinical development.

"The initiation of clinical testing for AB154 represents another
significant milestone for the Company, as we believe that anti-TIGIT
antibodies have the potential to be a new and important class of
backbone therapy in immuno-oncology," said Terry Rosen, Ph.D., Chief
Executive Officer at Arcus. "TIGIT is a unique immune checkpoint target,
because it is involved in a pathway that plays both immune inhibitory
and stimulatory roles in the tumor microenvironment. Our clinical
program for AB154 will focus on tumor types associated with high levels
of TIGIT or CD155, the primary ligand for TIGIT. We also look forward to
advancing our fourth product candidate, AB680, our small molecule CD73
inhibitor, into a clinical trial later this year, particularly given the
synergy that we have observed between AB154 and AB680 in our immune

AB154 is a blocking antibody, distinguishing it from some of the other
anti-TIGIT antibodies in clinical development, which have effector
function and rely on a mechanism involving the depletion of regulatory T
cells. The Company believes that the blocking mechanism may have both
efficacy and safety advantages relative to one that is based upon
regulatory T cell depletion.

The Phase 1, multi-center, open-label trial is designed to evaluate the
safety, pharmacokinetics, pharmacodynamics and clinical activity of
AB154 as a monotherapy and in combination with AB122, the Company's
anti-PD-1 antibody. The dose-escalation portion will first evaluate
increasing doses of AB154 as a monotherapy and subsequently in
combination with AB122. Once the recommended doses for AB154 as a
monotherapy and in combination with AB122 have been identified, the
Company plans to initiate expansion cohorts to evaluate AB154 as a
monotherapy and in combination with AB122 in selected tumor types. The
Company also plans to explore AB154 in combination with its other
product candidates.

The trial is initially being conducted in Australia, and the Company is
preparing to file an Investigational New Drug (IND) application with the
U.S. Food and Drug Administration (FDA) in the fourth quarter of 2018 to
initiate this trial in the United States. Preliminary data from the
dose-escalation portion of the Phase 1 trial are expected to be
presented in 2019.

About AB154

AB154 is a monoclonal antibody that potently and selectively blocks a
novel immune checkpoint called TIGIT. As are the targets (e.g., PD-1 and
CTLA-4) of some of the first-generation immune checkpoint inhibitors,
TIGIT is expressed on exhausted effector T cells, which may reside
within tumors but are unable to mount an effective attack against the
cancer cells. TIGIT is also expressed on a wide range of other
tumor-infiltrating immune cells, such as NK cells and regulatory T
cells. AB154 blocks the interaction between TIGIT and CD155, which is
highly expressed on many cancer cells, an interaction that results in an
inhibitory signal in immune cells. CD155 can also bind to CD226 on T
cells and NK cells, which results in a stimulatory signal. Therefore, by
binding to TIGIT, AB154 not only blocks an inhibitory signal but also
frees up CD155 to bind to CD226, thereby selectively activating the
immune system against cancer cells. Based on results from the Company's
preclinical assays, the Company believes this will result in a powerful
anti-tumor effect.

About AB122

AB122 is a fully human IgG4 antibody that potently and selectively
blocks PD-1. The biochemical, biological and preclinical properties of
AB122 have been shown to be similar to those of the marketed anti-PD-1
antibodies nivolumab and pembrolizumab. In August 2017, Arcus entered
into an agreement with WuXi Biologics for an exclusive license to
develop, use, manufacture, and commercialize AB122 worldwide except for
China and five other countries outside of the U.S., Europe and Japan. In
November 2017, dosing was initiated in Australia for the Phase 1 trial
of AB122 in cancer patients. The Company plans to report initial data
from this trial in the second half of 2018. The Company expects AB122 to
form the backbone of many of its intra-portfolio combination therapies.

About Arcus Biosciences

Arcus Biosciences is a clinical-stage biopharmaceutical company focused
on creating innovative cancer immunotherapies. Arcus has several
programs targeting important immuno-oncology pathways, including a dual
adenosine receptor antagonist AB928, which is in a Phase 1/1b program to
evaluate AB928 in combination with other agents in multiple tumor types,
and an anti-PD-1 antibody AB122, which is being evaluated in a Phase 1
trial and will be tested in combination with Arcus's other product
candidates. Arcus's other programs include AB154, an anti-TIGIT
antibody, which is in a Phase 1 trial to evaluate AB154 as monotherapy
and in combination with AB122, and AB680, a small molecule inhibitor of
CD73, which is in IND-enabling studies. Arcus has extensive in-house
expertise in medicinal chemistry, immunology, biochemistry, pharmacology
and structural biology. For more information about Arcus Biosciences,
please visit

Forward-Looking Statements

This press release contains forward-looking statements. All statements
other than statements of historical facts contained herein, including,
but not limited to, Arcus's regulatory and development timelines and the
potential for synergistic activity when Arcus's product candidates are
tested in combination, are forward-looking statements reflecting the
current beliefs and expectations of management made pursuant to the safe
harbor provisions of the Private Securities Litigation Reform Act of
1995. All forward-looking statements involve known and unknown risks,
uncertainties and other important factors that may cause Arcus's actual
results, performance or achievements to differ significantly from those
expressed or implied. Factors that could cause or contribute to such
differences include, but are not limited to, the inherent uncertainty
associated with pharmaceutical product development and clinical trials,
delays in our clinical trials due to difficulties or delays in the
regulatory process, enrolling subjects or manufacturing or supplying
product for such clinical trials, and the applicability of the studies
described herein to Arcus's current and future clinical trials. Risks
and uncertainties facing Arcus are described more fully in Arcus's
quarterly report on Form 10-Q for the quarter ended March 31, 2018 filed
on May 9, 2018 with the SEC. You are cautioned not to place undue
reliance on the forward-looking statements, which speak only as of the
date of this press release. Arcus disclaims any obligation or
undertaking to update, supplement or revise any forward-looking
statements contained in this press release.

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