Patrys : Appendix 4C - Quarterly - 31 December 2021

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ASX & Media Release

31 January 2022

Quarterly Activities Report and

4C Quarterly Cash Flow Report

Highlights from the quarter

• PAT-DX3manufacturing development program significantly ahead of schedule;
• Non-clinicalstudies further define biological and pharmaceutical profile of PAT-DX3 deoxymab and potential use for expanded clinical applications;
• Business development focus;
• Rodent, non-GLP toxicology studies confirm an acceptable safety and tolerability profile for PAT-DX1; and,
• Balance sheet capacity with closing cash balance of $10.76M at 31 Dec 2021, with an additional $2M in short-term investments.

Melbourne, Australia; 31 January 2022: Patrys Limited (ASX: PAB, "Patrys" or the "Company"), a

therapeutic antibody development company, today released its Quarterly Activities Report and Appendix 4C Quarterly Cash Flow report for the quarter ended 31 December 2021.

Patrys Chief Executive Officer and Managing Director, Dr. James Campbell said: "During the quarter,we have progressed the development of both of our deoxymabs assets, PAT-DX1and PAT-DX3.The non-clinicalstudies that we completed during this quarter have highlighted the opportunities of our expanded deoxymab platform, including their potential to be used as targeting agents for antibody drug conjugates (ADCs). Clearly, we are frustrated that the scale-uppurification of PAT-DX1in the engineering run has introduced a 6-monthdelay into our clinical program. Such technical issues, however, are not uncommon in the scale-upmanufacture of biological drugs and we remain confident that we will be able to address them and are looking forward to significant progress withboth assets in the coming months."

R&D Update

In Q4 CY 2021, Patrys initiated a formal development program for the commercial-scale production of clinical-grade drug material of its full-sized IgG deoxymab antibody, PAT-DX3. Progress for this

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program has exceeded expectations, with multiple cell lines already meeting the prespecified selection criteria required for commercial scale production. The Company intends to identify and select a cell line for commercial-scale production of clinical-gradePAT-DX3 antibody in coming months. The upstream and downstream development programs have also advanced faster than expected, these are critical steps in preparation for PAT-DX3 manufacturing.

During the quarter, Patrys also completed several studies which compared the biological activity and pharmaceutical profiles of PAT-DX1 and PAT-DX3. These studies have shown, that like PAT-DX1, PAT- DX3 is able to cross the blood brain barrier in animal models of brain cancer and penetrate cancer cells. PAT-DX3 appeared to have a higher affinity for DNA than PAT-DX1, suggesting that it may be more efficacious than PAT-DX1. Indeed, in an animal model of colon cancer, PAT-DX3 was more effective at reducing tumour growth and increasing survival than PAT-DX1. In addition, Patrys reported that PAT-DX3 was able to be used as a targeting agent to deliver an anticancer drug and inhibit tumour growth and increase survival in an animal model of human breast cancer. This data set confirmed that PAT-DX3 has therapeutic potential both as a single agent and as a targeting agent for antibody drug conjugates (ADCs), and the Company is accelerating non-clinical development of this asset through its global network of collaborators and suppliers.

During the December quarter, Patrys completed a non-GLP (Good Laboratory Practice) toxicology study in rodents for its lead asset PAT-DX1. This study found that PAT-DX1 was safe and well-tolerated at all doses tested with no mortalities or significant changes to body weight. A range of biochemical tests were conducted as part of this study which confirmed safety and tolerance. A similar set of non- GLP toxicology studies with PAT-DX1 in non-human primates will be initiated in coming months.

Corporate Update

The Company was actively involved in a range of global business development conferences during the quarter under review. These meetings have resulted in several ongoing discussions with a range of pharmaceutical and biotech companies who are attracted to both the anti-cancer activity of deoxymabs generally, and the specific potential of PAT-DX3 to be used in ADCs for targeted intracellular delivery of cancer drugs and a range of other payloads such as nucleic acids. ADCs continue to be one of the most commercial active areas in terms of deal making with substantial licensing deals being announced by Genmab, ADC Therapeutics, and Legochem in recent months.

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In the 3 months ended 31 December 2021, Patrys successfully raised $7.8M via a Placement and fully underwritten Rights Issue. Patrys is extremely grateful for the strong support provided by its shareholders during 2021, which has put the Company in a strong fiscal position with the financial capacity to advance both its assets, PAT-DX1 and PAT-DX3 towards the clinic.

In October 2021, Ms. Melanie Leydin stepped down as Company Secretary and was replaced by Mr. Stefan Ross. Mr. Ross has over 10 years of experience in accounting and secretarial services for ASX-listed companies, with extensive experience in ASX compliance, corporate governance control and implementation, statutory financial reporting and board and secretarial support.

During the quarter ended 31 December 2021, Patrys had net cash outflows of A$4.58M, with A$4.20M invested in R&D activities. At the conclusion of the quarter, Patrys held A$10.76M in cash and A$2.0M in short-term investments, a total of $A12.76M, and remains in a strong financial position. Payments to related parties and their associates during the quarter as outlined in Section 6 of the accompanying Appendix 4C to this quarterly activities report were A$145k. These payments are related to executive director salary, non-executive director fees and consulting services for the quarter.

Subsequent events

Subsequent to the end of the quarter, Patrys provided an update on the engineering run of PAT-DX1 that was being conducted to provide GLP-quality drug material for the remaining toxicology studies and the planned Phase-1 clinical trial. The product yield from the fermentation process was consistent with a previous small scale pilot production run. However, the scaled-up process for purifying PAT-DX1 from the harvested cells resulted in lower recoveries than had been experienced previously. As a result, the final yield of GLP-qualityPAT-DX1 did not provide sufficient drug material to conduct the final GLP toxicology studies needed before the planned Phase-1 clinical trial of PAT-DX1. Patrys is working with its Contract Development Manufacturing Organisation (CDMO) to implement improvements to this scaled-up purification process. Based on work conducted by the CDMO to date, it is anticipated that an additional engineering run for PAT-DX1 using an improved large-scale purification process will commence in Q2 CY2022. While Patrys fully expects this technical issue will be resolved, the need to conduct an additional manufacturing run for PAT-DX1 means that the final

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GLP toxicology studies, and consequently the Phase-1 clinical trial of PAT-DX1, will be delayed by approximately 6 months.

On 24 January 2022, Patrys announced it had received $1.2M under the Australian Government's R&D Tax Incentive scheme for eligible research activities conducted during FY21 (ending 30 June 2021).

-Ends-

This announcement is authorised for release by the Board of Directors of Patrys Limited.

For further information, please contact:

General enquiries	Media enquiries:
James Campbell	Haley Chartres
Chief Executive Officer	H^CK
P: [phone]	P: [phone]
[e-mail]	[e-mail]
Registered Office Address
Level 4, 100 Albert Road
South Melbourne VIC 3205

About Patrys Limited

Based in Melbourne, Australia, Patrys (ASX:PAB) is focused on the development of its deoxymab platform of cell-penetrating antibodies as therapies for a range of different cancers. More information can be found at www.patrys.com.

About Patrys' deoxymab platform:

Patrys' deoxymab platform is based on the deoxymab 3E10 antibody that was first identified as an autoantibody in a mouse model of the human disease systemic lupus erythematosus (SLE). While most antibodies bind to cell surface markers, deoxymab 3E10 penetrates into the cell nuclei and binds directly to DNA where it inhibits DNA repair processes. Cancer cells often have high levels of mutations and underlying deficiencies in the DNA repair mechanisms. For these reasons, the additional inhibition of the DNA repair processes by deoxymab 3E10 can kill cancer cells, but appears to have little impact on normal cells. As a single agent, deoxymab 3E10 has been shown to significantly enhance the efficacy of both chemo- and radiotherapies. Further, deoxymab 3E10 can be conjugated to payloads including small molecules, nanoparticles and imaging agents to target delivery to tumours.

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Patrys has developed two humanised forms of deoxymab, both which have improved activity over the original deoxymab 3E10 antibody. PAT-DX1 is a dimer (two joined subunits) of the short chain from the binding domain of deoxymab, while PAT-DX3 is a full-sized IgG antibody. In a range of pre-clinical studies, PAT-DX1 has shown significant ability to kill cancer cells in cell models, human tumour explants, xenograft, and orthotopic models. PAT-DX1 has been shown to cross the blood brain barrier, reduce tumour size, and increase survival in multiple animal models of brain cancer and cancer metastases. PAT-DX1 has also been shown to reduce tumour size and increase survival in non-brain cancers such as triple negative breast cancer and pancreatic cancer. PAT-DX3 can cross the blood brain barrier to target cancers of the brain. Both PAT-DX1 and PAT-DX3 are tumour-agnostic, meaning that they can target many different tumour types in the body, regardless of specific tumour antigens. Patrys believes that PAT-DX1 and PAT-DX3 may have application across a wide range of cancers including gliomas, melanomas, prostate, breast, pancreatic, and ovarian cancers.

Patrys has completed proof of concept studies showing that it is possible to conjugate small molecule payloads to PAT-DX3, and is advancing antibody drug conjugate (ADC) efforts using deoxymabs. In addition, deoxymabs such as PAT-DX1 and PAT-DX3 can be used to target nanoparticles carrying a payload of anti-cancer drugs specifically to tumours. This allows specific delivery of cancer drugs to multiple types of cancer while having minimal impact on normal, healthy cells.

Patrys' rights to deoxymab are part of a worldwide license to develop and commercialise a portfolio of novel anti-DNA antibodies and antibody fragments, variants and conjugates discovered at Yale University as anti-cancer and diagnostic agents. To date, seven patents have been granted across the deoxymab portfolio. Six patents protecting deoxymabs (and derivatives thereof) have already been granted (Europe, Japan, China, and 3 in the USA), and one patent covering nanoparticle conjugation to deoxymabs has been granted (Australia).

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