Vanucizumab
(also known as RO5520985; RG7221) is
a novel bi-specific human Immunoglobulin G (IgG1) monoclonal antibody that
simultaneously binds to two key angiogenic factors, Vascular Endothelial Growth
Factor A (VEGF-A) and Angiopoietin-2 (Ang-2). The bi-specific monoclonal
antibody comprise of two different heavy chains and two different light chains.
One arm of the antibody binds Angiopoietin-2 (Ang2) Ang-2 which is based
on LC06, an Ang-2 selective human IgG1 antibody. The other is based on Bevacizumab which binds Vascular Endothelial Growth Factor A (VEGF-A) [1, 2].
VEGF-A
blockade has been clinically validated as a treatment for human cancers.
Angiopoietin-2 (Ang-2) expression has been shown to function as a key regulator
of tumor angiogenesis and metastasis. The antibody is designed to inhibit both
VEGF-A and Ang2 simultaneously to offer superior clinical benefit compared to
VEGF-A inhibition alone.
Vanucizumab
came to Roche after it acquired Genentech and the bi-specific monoclonal
antibody was intended as follow-on to Genentech blockbuster cancer drug, Bevacizumab.
On Oct
20, 2016, parent company Roche opted to discontinue the development of Vanucizumab
as a cancer monotherapy on a Phase II trial failure. Though no specific reasons
where provided but it is strongly felt that a bi-specific monoclonal antibody
such as Vanucizumab although delays tumor growth, it fails to achieve long-term
inhibition of tumor growth. Hence, it fails to deliver the value for dual
inhibition of VEGF-A and Ang-2. Roche is proceeding with clinical trials for
Vanucizumab in combination therapy with other anti-cancer drugs.
Tumor Angiogenesis and Treatments:
Angiogenesis,
the formation of new blood vessels from pre-existing ones, plays a central role
in the process of tumor growth and metastasis. The proliferation of endothelium
and formation of new blood vessels further the size of solid tumors. It is
expected that blocking angiogenesis will be an efficient therapeutic approach
against many tumor types. The key signaling system that regulates proliferation
and migration of endothelial cells are vascular endothelium growth factor
(VEGF) and their receptors (VEGFR-1, -2 and -3). VEGFR-2, a receptor with
higher affinity and greater kinase activity, is more important in the direct
regulation of angiogenesis, mitogenic signaling, and permeability-enhancing
effects. VEGFRs are expressed at high levels in many types of human solid
tumors, including glioma, lung, breast, renal, ovarian and gastrointestinal
tract carcinomas. Inhibition of VEGFR has emerged as a potential therapy method
for cancers and it has been clinically validated with FDA-approvals of
bevacizumab, sorafenib, and suntinib [3].
The
clinical efficacy of angiogenesis inhibitors targeting VEGF marked a milestone
in the field of angiogenesis research; however overlapping and compensatory
alternative angiogenic pathways provide escape mechanisms that likely limit the
full potential of VEGF monotherapies [3].
The
Tie2 receptor ligands, angiopoietin-1 and angiopoietin-2 (Ang-1 and Ang-2),
have been implicated in the remodeling of the tumor vasculature. Ang-1 acts as
a regulator of vascular maturation and stabilization. In contrast, Ang-2
promotes angiogenesis and tumor growth by (i) destabilizing Tie2 expressing stalk
cells, thereby priming the vasculature to respond to angiogenic stimuli, and
(ii) induction of sprouting tip cell migration in a Tie2-independent manner via
integrins. Ang-2 can be responsible for compensatory tumor revascularization
and growth during anti-VEGF therapy and has been shown to interfere with
anti-VEGFR-2–induced vessel normalization. In several tumor indications,
upregulated Ang-2 levels are a poor prognostic factor and correlate with
disease progression and metastasis. Accordingly, Ang-2 was identified as a
regulator of glioma, breast cancer, and melanoma cell migration and invasion,
and has been shown to drive lymphatic metastasis of pancreatic cancer. Recent
data also demonstrated that Ang-2 inhibitors, both as single agents or in
combination with anti-VEGF therapy mediate antitumor effects and interfere with
metastasis formation. Recently, different approaches have been described to
target the angiopoietin/Tie axis in clinical trials.
Given
the cooperative and complementary fashion of Ang-2- and VEGF-induced
angiogenesis and metastasis, co-targeting of both ligands in a bispecific
manner represents an encouraging approach to improve the outcomes of current
antiangiogenic therapies. A number of bispecific antibodies have been described
in the literature. As most bispecific antibody formats deviate significantly
from the natural IgG format, researchers aimed to develop bispecific antibodies
that differ only minimally from natural occurring antibodies. Their efforts
resulted in a novel method for the production of heterodimeric bivalent
bispecific human IgG1 antibodies (CrossMabs) that display the classical IgG
architecture, and exhibit favorable IgG-like properties in terms of pharmacokinetic,
diffusion, tumor penetration, production, and stability [4].
Ang-2-VEGF-A
CrossMab is being developed for the treatment of multiple cancer indications
aiming to substantially improve clinical outcomes [5, 6].
Mechanism of Action in Vanucizumab:
Vanucizumab
is a bi-specific human IgG1 monoclonal antibody designed to inhibit both VEGF-A
and Ang2 simultaneously.
Dosages and Approvals:
Vanucizumab
(Tradename: -) is being developed by
Roche as an antiangiogenic agent in the treatment of various cancers.
Reported Activities for Vanucizumab:
Vanucizumab
led to strong inhibition of angiogenesis with enhanced vessel maturation and
demonstrated potent tumor growth inhibition, superior to single pathway
inhibitors in a panel of preclinical models.
Dual
targeting of Ang-2 and VEGF-A slows down tumor growth in a variety of tumor
models. With regards to the clinical situation, studies show that Ang-2-VEGF-A
dual targeting exerts better therapeutic effects especially on larger tumors as
compared with the monotherapies. In the light of recent findings which support
the hypothesis that larger tumors consist of different vessel types that do not
all respond equally to anti-VEGF-A therapy, such a therapeutic profile is of
special interest.
Interestingly,
in addition to its antiangiogenic effects, Ang-2 targeting was reported to have
additional beneficial effects on tumor metastasis inhibition. Moreover, a
positive correlation between Ang-2 overexpression and metastasis can be
observed in the clinic.
Summary
Common name: RO-5520985;
RO5520985; RO 5520985; RG-7221; RG7221; RG 7221; Anti-VEGF-A; Anti-Ang-2;
Ang-2-VEGF-A CrossMab; A2V CrossMab; Vanucizumab
Trademarks: -
Molecular Formula: -
CAS Registry Number: 1448221-05-3
CAS Name: -
Molecular Weight: -
SMILES: -
InChI Key: -
InChI: -
Mechanism of Action: Angiogenesis Inhibitors;
Vascular Endothelial Growth Factor A (VEGF-A) Inhibitors; Angiopoietin-2
(Ang-2) Inhibitors; Monoclonal Antibodies (mAbs); Bi-Specific Monoclonal
Antibodies
Activity: Antineoplastics; Angiogenesis
inhibitors
Status: Under Phase Trials
Chemical Class: Monoclonal
Antibodies (mAbs); Bi-Specific Monoclonal Antibodies; Cross MAB
Originator: Roche
Originator: Roche