Opthea Ltd — Major Shareholding Notification 2010

Mar 25, 2010

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26 March 2010

The Companies Section The Australian Stock Exchange Limited 530 Collins Street MELBOURNE VIC 3000

Dear Sir/Madam

Substantial Holding Notice for Antisense Therapeutics Limited

We enclose Form 604 “Notice of Change of Interests of Substantial Holder” with respect to holdings in Antisense Therapeutics Limited by Polychip Pharmaceuticals Pty Ltd (Polychip) (a wholly owned subsidiary of Circadian Technologies Limited) and Syngene Limited (an associate - 42.38% owned by Polychip).

Yours faithfully

Natalie Korchev Company Secretary

Level 1, 10 Wallace Avenue, Toorak, Victoria 3142, Australia P: +61 (3) 9826 0399 Circadian Technologies Limited F: +61 (3) 9824 0083 ABN 32 006 340 567 www.circadian.com.au

FORM 604

Corporations Act 2001 Section 671B

NOTICE OF CHANGE OF INTERESTS OF SUBSTANTIAL HOLDER

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To: ANTISENSE THERAPEUTICS LIMITED (ANP) ACN: 095 060 745

1. Details of substantial holder (1)

Name: POLYCHIP PHARMACEUTICALS PTY LTD (POLYCHIP) (A WHOLLY OWNED SUBSIDIARY OF CIRCADIAN TECHNOLOGIES LIMITED): AND SYNGENE LIMITED (SYNGENE) (42.38% OWNED BY POLYCHIP) ACN: 006 455 456 (POLYCHIP) 006 161 753 (SYNGENE)

There was a change in the interests of the substantial holder : Due to transactions by the holder on: 24/3/2010 The previous notice was given to the company on: 5/2/2010 The previous notice was dated: 5/2/2010

2. Previous and present voting power

The total number of votes attached to all the voting shares in the company or voting interests in the scheme that the substantial holder or an associate (2) had a relevant interest (3) in when last required, and when now required, to give a substantial holding notice to the company or scheme, are as follows:

Class of securities (4)	Previous notice	Previous notice	Previous notice		Present notice	Present notice
	Person’s votes		Voting power (5)		Person’s votes	Voting power (5)
Ordinary: Polychip Syngene LimitedA Total	106,906,497 35,259,412 142,165,909		18.14% 5.98% 24.12%		101,906,497 30,259,412 132,165,909	17.29% 5.13% 22.42%

A Polychip Pharmaceuticals Pty Ltd has a 42.38% interest in Syngene Limited and Syngene Limited owns 30,259,412 ordinary shares in Antisense Therapeutics Limited.

3. Changes in relevant interests

Particulars of each change in, or change in the nature of, a relevant interest of the substantial holder or an associate in voting securities of the company or scheme, since the substantial holder was last required to give a substantial holding notice to the company or scheme are as follows:

Date of change	Person whose relevant interest changed	Nature of change (6)	Consideration given in relation to change (7)	Class and number of securities affected	Person’s votes affected (no. of shares)
24/3/10	Polychip	Sale of 5,000,000 ordinary ANP shares by Polychip which has decreased Polychip’s interests in ANP.	$153,000	5,000,000 ordinary shares.	5,000,000 votes.
24/3/10	Syngene	Sale of 5,000,000 ordinary ANP shares by Syngene which has decreased Syngene’s interests in ANP.	$153,000	5,000,000 ordinary shares.	5,000,000 votes.

4. Present relevant interests

Particulars of each relevant interest of the substantial holder in voting securities after the change are as follows:

Holder of relevant interest	Registered holder of securities	Person entitled to be registered as holder (8)	Nature of relevant interest (6)	Class and number of securities	Person’s votes
Polychip Pharmaceuticals PtyLtd	Polychip Pharmaceuticals Pty Ltd	Polychip Pharmaceuticals PtyLtd	Beneficial Owner	Ordinary shares 101,906,497	101,906,497
Syngene Limited (Polychip has a 42.38% interest in Syngene)	Syngene Limited	Syngene Limited	Beneficial Owner	Ordinary shares 30,259,412	30,259,412

5. Changes in association

The persons who have become associates (2) of, ceased to be associates of, or have changed the nature of their association (9) with, the substantial holder in relation to voting interests in the company or scheme are as follows:

Name and ACN (if applicable)	Nature of association
Not applicable

6. Addresses

The addresses of persons named in this form are as follows:

Name	Address (Registered Office)
PolychipPharmaceuticalsPtyLtd	Level 1,10 WallaceAvenue,Toorak, Victoria
Circadian TechnologiesLimited	Level 1,10 WallaceAvenue,Toorak, Victoria
SyngeneLimited	Level 1,10 WallaceAvenue,Toorak, Victoria

Signed by:

Natalie Korchev Company Secretary 26 March 2010