avexa reports positive phase iib result

Avexa Limited
ABN 53 108 150 750
576 Swan Street Richmond
Victoria Australia 3121
Telephone 61 3 9208 4300
Facsimile 61 3 9208 4004
Website www.avexa.com.au
ASX Release
19th March 2007
Avexa reports positive Phase IIb result
ATC shows superior activity
Australian biotechnology company Avexa (ASX: AVX) today announced highly successful
results from its Phase IIb trial for apricitabine (ATC). ATC is Avexa’s novel nucleoside reverse
transcriptase inhibitor (NRTI) being developed for the treatment of HIV infection in patients
with drug-resistant HIV.
The Phase IIb trial compared the effectiveness of ATC in reducing the viral load of patients with
drug-resistant HIV with the effectiveness of lamivudine (3TC), a leading NRTI in widespread
use. A total of 47 patients completed 21 day dosing. Of these 17 patients received 600 mg doses
of ATC, 16 received 800 mg doses of ATC and the control group of 14 patients were treated
with 3TC.
The results for patients in both ATC cohorts exceeded the Phase IIb trial primary endpoint by a
substantial margin. Patients who received ATC achieved on average a reduction of greater than
0.8 log10 (85%) in the level of HIV in the blood after 21 days treatment compared to a reduction
of less than 0.03 log10 in patients treated with 3TC. Nine patients achieved a greater than 1.5 log
10 (97%) reduction after 21 days, with 3 patients achieving a reduction of over 2.0 log 10 (99%).
Remarkably, one patient achieved a decrease in the amount of virus of more than 2.5 log10
(99.7%) after 21 days on ATC. Patients with the highest degree of drug resistance still achieved
a significant benefit from treatment with ATC. The demonstration of superior activity in this
study indicates that ATC will be an effective antiviral drug for the treatment of many drugresistant
patients, including even those most highly resistant.
“This is a fantastic result for Avexa” stated CEO Dr Julian Chick. “The positive result allows us
to continue to progress ATC into Phase III trials and towards commercialisation. The team at
Avexa has done a great job and these excellent results show that their hard work has paid off.”
During the study there were no Serious Adverse Events (SAEs) related to the study drug, and no
patients withdrew from the study because of side effects of study drug treatment. ATC continues
to be very well tolerated, with some patients having received more than 12 months treatment to
date. Currently there are 14 patients in the open label section of the Phase IIb trial and 6 patients
have elected to enter into an extension study (where they continue to be treated with ATC),
having completed the full 48 weeks of the study.
“These outstanding results clearly position ATC to become the most effective and well tolerated
NRTI for treatment of drug-resistant HIV” stated Dr Jonathan Coates, Avexa’s CSO, and coinventor
of 3TC, a NRTI marketed by GSK.

Avexa Limited
ABN 53 108 150 750
576 Swan Street Richmond
Victoria Australia 3121
Telephone 61 3 9208 4300
Facsimile 61 3 9208 4004
Website www.avexa.com.au
The emergence of resistance to antiviral drugs is one of the most important reasons for treatment
failure. No evidence of mutation in the virus resulting in resistance to ATC was detected over the
course of the 21 day treatment. This indicates that antiviral resistance to ATC does not occur
quickly and gives ATC a significant competitive advantage over several other drugs which can
rapidly select for resistance.
“Overall the results of Avexa’s Phase IIb clinical trial demonstrate that ATC is a clinically
effective antiviral drug that can significantly reduce the replication of the virus in patients
infected with drug-resistant HIV” said CEO Dr Julian Chick. “Moreover, these results
demonstrate that ATC is a safe drug not associated with undesirable side effects. In addition,
there was no evidence of ATC resistant virus emerging over the trial period. All these results
indicate that ATC has the properties required to position it as the NRTI of choice for the
treatment of patients failing their first line or subsequent anti-HIV drug regimens.”
Global HIV market
It is estimated that over 40 million people are currently infected with HIV, with over 1 million of
these children. It is currently estimated that around 1.4 million people in North America and
around 2.2 million people in Europe have HIV.
Once on therapy, patients with HIV will typically take a minimum of 3 drugs daily in
combination. This may increase as a patient progresses into 2nd and 3rd line therapy or into
salvage therapy, when patients have developed what is commonly referred to as AIDS. Second
line patients are defined as patients who show resistance to at least one class of HIV drugs, while
3rd line and salvage patients typically have resistance to multiple drugs and drug classes. Avexa
is aiming to position ATC as the NRTI of choice for the treatment for patients in 2nd and 3rd line
therapy and salvage therapy, as well as for the growing number of treatment naïve patients
presenting with HIV virus resistant to the current front line therapies. In 2005 HIV drugs
generated sales globally of USD $6.6 billion, with NRTIs representing greater than 50% of the
overall market.
For more information:
Dr. Julian Chick Mr. Rod North
Chief Executive Officer Bourse Communications
+61 (03) 9208 4300 + 61 (03) 9510 8309
Avexa Limited is a Melbourne-based biotechnology company with a focus on research and development of
drugs for the treatment of infectious diseases, in particular diseases which have a significant unmet medical
need. Avexa has dedicated resources and funding for key projects including antiviral drugs for HIV and an
antibiotic alternative for antibiotic-resistant bacterial infections. The Company’s lead program is apricitabine
(ATC) which has recently successfully completed the 21 day dosing of its Phase IIb trial. The Company
continues to progress ATC towards Phase III trials.

Avexa Limited
ABN 53 108 150 750
576 Swan Street Richmond
Victoria Australia 3121
Telephone 61 3 9208 4300
Facsimile 61 3 9208 4004
Website www.avexa.com.au
Technical Data
Trial Design
AVX-201 is a randomised, double blind study of two doses of ATC compared to lamivudine
(3TC) in treatment-experienced HIV-1 infected patients with the M184V mutation. Patients were
randomised to receive 600mg or 800mg ATC twice daily, or 3TC twice daily, for 21 days, in a
blinded fashion. The primary endpoint of the study is the change in the amount of virus in the
blood (viral load) after 21 days treatment.
After day 21, patients continue to receive either ATC or 3TC up to week 24, but can also change
their other background HIV medicines. After week 24, all patients openly receive ATC unblinded
to week 48. After week 48, patients may elect to enter an extension study (AVX-201E) in which
they continue to receive ATC in addition to their other HIV medicines.
47 patients were analysed after 21 days of treatment. Approximately one third were female, and
approximately half had the highest levels of drug resistance. The majority of the patients were
recruited in Argentina, with patient ages ranging from 22 to 59.
Efficacy data
Bars on the figure above indicate the standard error of the two groups.

Avexa Limited
ABN 53 108 150 750
576 Swan Street Richmond
Victoria Australia 3121
Telephone 61 3 9208 4300
Facsimile 61 3 9208 4004
Website www.avexa.com.au
Safety data
No ATC drug-related serious adverse events have been observed to date. No patients have been
withdrawn from the trial because of side effects related to ATC treatment. In particular there has
been no significant incidence of hyperlipasaemia (an indicator of pancreatitis) or elevated liver
enzymes (suggestive of liver toxicity) related to ATC. These are two serious and undesired sideeffects
associated with some other NRTIs. These data demonstrate the good safety profile for
ATC in the clinical setting.
Full scientific data from the Phase IIb trial will be presented at an upcoming international
scientific conference.