the cohorts of patients receiving 1.7 mg/kg of ARX788 Q3W, with a
43% (3 out of 7) confirmed ORR, 1.5 mg/kg of ARX788 Q3W, with a 46%
(6 of 13 patients) confirmed ORR, and a 43% (3 of 7 patients)
confirmed ORR in the cohort of patients receiving 1.3 mg/kg of
ARX788 at Q3W as of December 14, 2021. We have received Orphan
Drug designation from the FDA for the treatment of gastric cancer,
including cancer at the GEJ. Treatment with ARX788 in the
ACE-Pan
tumor-01
and
trials has also been generally well-tolerated and while most
patients in these trials have experienced at least one drug-related
adverse event, there have only been an aggregate of eight
drug-related serious adverse events (SAEs) reported from the 183
patients dosed with ARX788 in these trials as of March 31,
2022.
Based on clinical data generated to date, we initiated
our first global, potentially pivotal trial for HER2-positive
metastatic breast cancer. As of March 31, 2022, 13 patients
have been treated. We expect to report preliminary results in
2023.
Within our ADC franchise, we also have two earlier-stage product
candidates: ARX517, an anti-PSMA ADC for the treatment of prostate
cancer and other solid tumors for which we initiated a Phase 1
clinical trial in 2021 and are currently in dose escalation to
identify the recommended Phase 2 dose, and ARX305, an anti-CD70 ADC
for the treatment of renal cell carcinoma (RCC) and other cancers.
The Investigational New Drug (IND) application for ARX305 received
FDA clearance in February 2022. We anticipate that we will start
the first in human trial for ARX305 in 2022. Additionally, our IOC
franchise consists of multiple product candidates targeting broad
immuno-oncology applications. These candidates include ARX822, a
CD3-folate
bispecific, and ARX102, a smart
cytokine. We are currently conducting
IND-enabling
studies for ARX102 with an IND expected to be submitted in the
second half of 2022. Additionally, we have several ongoing
collaborations with large global pharmaceutical companies. These
collaborations include three clinical-stage programs and several
earlier-stage preclinical programs. In connection with our pipeline
programs and platform technologies, we own or control over 850
issued patents and pending patent applications.
Our mission is to discover and develop a pipeline of EPBs to treat
a broad range of diseases and disorders, with an initial focus on
cancers with a high unmet medical need. We believe that combining
our pioneering efforts in expanded genetic code and site-specific
bio-conjugates
with a team of dedicated professionals bound by a culture and
vision that embraces innovation, practicality, and accountability
will allow us to pursue our mission.
Conventional
Biologics and
Bio-Conjugates,
and Their Inherent Limitations
Biologics have been used increasingly on a global basis and in
multiple therapeutic areas, expanding the overall drug market and
reducing the market share of small molecule drugs. The market for
biologics initially included conventional biologics such as
insulin, growth hormones, and monoclonal antibodies. However,
despite the clinical benefit provided by these natural peptides and
antibodies, there remained a significant need for more effective
therapies. Since then, the industry has developed
bio-conjugates
to generate more efficacious treatments, including approved drugs
such as Enhertu (trastuzumab deruxtecan), Adcetris (brentuximab
vedotin), Kadcyla
(ado-trastuzumab
emtansine) and Trodelvy (sacituzumab govitecan).
Bio-conjugates
are the product of joining two or more biologically active
components into a single drug. These constructs can introduce new
mechanisms of action, increase efficacy, reduce toxicity, and
provide improved clinical outcomes and convenience.
Bio-conjugates
have also significantly expanded the potential landscape of targets
that can be accessed by conventional biologics by providing several
new approaches for each target, such as an ADC or an ISAC.
Today’s leading
bio-conjugates
typically rely on cysteine and lysine, two naturally occurring
amino acids with “handles” for conjugations. Unfortunately,
utilizing natural amino acids for conjugation can limit drug design
in several ways. First, the conjugation chemistry is predetermined
with limited room to optimize reactivity, stability and
selectivity. Second, the location and number of these natural amino
acids within the protein further diminish the ability to control
the site of conjugation and the number of conjugations. Third,
additional manufacturing steps and controls are required for
conventional conjugations. As such, conventional conjugation
techniques result in a mixture of random,
non-uniform
and
un-optimized
drug conjugates that can potentially limit therapeutic efficacy and
introduce drug safety concerns.