Onxeo S.A.: Combination of AsiDNA and PARP Inhibitors Demonstrates Synergistic Effect, Bypasses Genetic Restriction

Preclinical Research Published in Clinical Cancer Research
PARIS & COPENHAGEN, Denmark--(BUSINESS WIRE (http://www.businesswire.com/))--
Regulatory News:

Onxeo S.A. (Paris:ONXEO) (NASDAQ OMX:ONXEO) (Euronext Paris, Nasdaq Copenhagen:
ONXEO), an innovative company specialized in the development of orphan oncology
therapeutics, today announced results from a preclinical study demonstrating
that the synergistic effect of its lead signal-interfering DNA product candidate
AsiDNA™ in combination with various products in the PARP (PolyADP-Ribose
Polymerase) inhibitor class of drugs is able to bypass the genetic restriction
of PARP inhibitors.

The results, which establish potential for rapid clinical translation, were
recently published online in the article “Drug Driven Synthetic Lethality:
bypassing tumor cell genetics with a combination of Dbait and PARP
inhibitors (http://cts.businesswire.com/ct/CT?id=smartlink&url=http%3A%2F%2Fclin
c 
ancerres.aacrjournals.org%2Fcontent%2Fearly%2F2016%2F08%2F24%2F1078-0432.CCR-16
-1193.abstract&esheet=51415471&newsitemid=0&lan=en
-US&anchor=Drug+Driven+Synthetic+Lethality%3A+bypassing+tumor+cell+genetics+with
+ 
a+combination+of+Dbait+and+PARP+inhibitors&index=1&md5=e420239c375a522abafd8a4d5
8 
c9cd45)” in the peer-reviewed journal Clinical Cancer Research. The print issue
is expected to be published in the coming weeks.

The preclinical study characterized the DNA repair inhibition activity of AsiDNA
and olaparib – by monitoring DNA repair and DNA damage, and analyzed cell
survival to standalone and combined treatments of 21 different tumor cell lines,
including 12 breast cancer cell lines, and 3 non-tumor cells.

Olaparib is a PARP inhibitor, blocking the enzyme PARP involved in tumor DNA
repair, with efficacy validated in patients with BRCA gene mutation, leading to
accumulation of DNA double-strand breaks which cannot be repaired. Olaparib is
approved for women with BRCA-mutated advanced ovarian cancer.

Results showed that olaparib and AsiDNA prevent recruitment of different
targeted repair enzymes to damaged sites, and the combination of both drugs
increases the accumulation of unrepaired damage, resulting in a synergistic
increase of cell death in all tumor cells. Synergistic efficacy of the
combination treatment was observed in all tested tumor models regardless of BRCA
status, while no increase of DNA damage, nor lethality was observed in healthy
cells, suggesting a good safety and tolerability profile. Analysis also
demonstrated different molecular mechanisms underlying the response to AsiDNA
and olaparib, suggesting that drug resistance to the combination would be a very
rare event. Furthermore, the study also showed that the combination with AsiDNA
is effective using six different PARP inhibitors, with no toxicity in non-tumor
cells.

Graham Dixon, PhD, Chief Scientific Officer of Onxeo, commented, “PARP
inhibitors show significant benefit in cancer patients, but are mostly limited
to tumors with BRCA mutations. AsiDNA breaks the cycle of tumor DNA repair by
interfering upstream of the DNA repair process, thereby blocking multiple repair
pathways and preventing repair regardless of genetic mutation. Combining AsiDNA
with already well-researched and FDA-approved PARP inhibitors like olaparib
presents a novel, clinically-viable strategy with broad applicability. These
preclinical results support Onxeo’s strategic assessment and advancement plan
for AsiDNA, and bolster our options for continued clinical development of AsiDNA
as a monotherapy and in combination with anti-cancer agents.”

About AsiDNA

AsiDNA is a signal interfering DNA repair pathway inhibitor being developed by
Onxeo as an anti-cancer agent. As a short double-stranded DNA molecule, AsiDNA
utilizes a unique mechanism of action to break the cycle of tumor DNA repair by
interfering at the core of DNA damage, blocking multiple repair pathways, while
sparing healthy cells. A first-in-human Phase I clinical trial evaluating AsiDNA
in combination with radiotherapy for treatment of patients with metastatic
melanoma showed AsiDNA is well tolerated and demonstrated proof of efficacy,
with an objective response rate of 59% and a complete response rate of 30%
compared to 10% CR with radiotherapy alone. Onxeo is currently accelerating a
comprehensive advancement plan for AsiDNA as monotherapy and in combination with
anti-cancer agents to offer potential new treatment options for patients
suffering from various types of cancer.

About Onxeo

Onxeo is a leading developer of orphan oncology drugs. The Company is focused on
developing innovative therapeutics for rare cancers, one of the fastest growing
markets in the healthcare industry with high, unmet medical needs. Onxeo’s
vision is to become a global leader and pioneer in oncology, with a focus on
orphan or rare cancers, by developing advanced, effective, and safe therapeutics
designed to improve the lives of patients. Onxeo’s comprehensive portfolio
features a broad orphan oncology pipeline, with four independent programs in
various stages of clinical development, including Onxeo’s first approved orphan
oncology drug, Beleodaq®. The Company is headquartered in Paris, France and has
approximately 50 employees. Onxeo is listed on Euronext in Paris, France
(Ticker: ONXEO, ISIN Code: FR0010095596) and Nasdaq Copenhagen, Denmark (Ticker:
ONXEO).

Onxeo’s orphan oncology products are:

  · Livatag® (Doxorubicin Transdrug™): Currently being evaluated in a Phase III
trial (ReLive) in patients with hepatocellular carcinoma (primary liver cancer);
and in combination with other cancer agents in first-line HCC
  · Beleodaq® (belinostat): FDA-approved in the US in 2014 under the agency’s
accelerated approval program as a second-line treatment for patients with
peripheral T-cell lymphoma (PTCL) and currently marketed by Onxeo’s partner in
the US, Spectrum Pharmaceuticals; belinostat in combination with other cancer
agents is currently in development in first-line treatment for patients with
PTCL (BelCHOP) and in other solid tumors
  · AsiDNA: The first-in-class siDNA (signal-interfering DNA) which has
successfully undergone a proof-of-concept Phase I trial in metastatic melanoma
  · Validive® (Clonidine Lauriad®): Positive final results from a Phase II trial
in head and neck cancer patients with severe oral mucositis

In addition, Onxeo has successfully developed and registered two non-cancer
products, which are currently being commercialized in the U.S. and Europe.

Learn more by
visiting www.onxeo.com (http://cts.businesswire.com/ct/CT?id=smartlink&url=http%
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A%2F%2Fwww.onxeo.com&esheet=51415471&newsitemid=0&lan=en
-US&anchor=www.onxeo.com&index=2&md5=994bfa1037764686d3758e8ee4f272fc).

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Disclaimer

This communication expressly or implicitly contains certain forward-looking
statements concerning Onxeo and its business. Such statements involve certain
known and unknown risks, uncertainties and other factors, which could cause the
actual results, financial condition, performance or achievements of Onxeo to be
materially different from any future results, performance or achievements
expressed or implied by such forward-looking statements. Onxeo is providing this
communication as of this date and does not undertake to update any forward
-looking statements contained herein as a result of new information, future
events or otherwise. For a discussion of risks and uncertainties which could
cause actual results, financial condition, performance or achievements of Onxeo
to differ from those contained in the forward-looking statements, please refer
to the Risk Factors ("Facteurs de Risque") section of the 2015 Reference
Document filed with the AMF on April 29, 2016, which is available on the AMF
website (http://www.amf
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(www.onxeo.com (http://cts.businesswire.com/ct/CT?id=smartlink&url=http%3A%2F%2F
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Contacts
Onxeo S.A.
Judith Greciet, CEO
Nicolas Fellmann, CFO
+33 1 45 58 76 00
investors@onxeo.com
or
Alize RP (France)
Caroline Carmagnol / Florence Portejoie, +33 6 64 18 99 59 / +33 6 47 38 90 04
onxeo@alizerp.com
or
The Ruth Group (U.S.)
Kirsten Thomas / Lee Roth, +1-508-280-6592 / +1-646-536-7012
kthomas@theruthgroup.com / lroth@theruthgroup.com