Silence Therapeutics: Post Year End Business Update

8 January 2018

Silence Therapeutics plc a leader in the discovery, delivery, and development of novel RNA therapeutics for the treatment of serious diseases with unmet medical need, announces a post year end update.

Arrowhead disposal and net cash position

In December 2016, given the dramatic decline in the valuation of Arrowhead Pharmaceuticals post clinical halts after discussion with the FDA, the Board decided to deploy our balance sheet to take a c10% stake in Arrowhead with a view to and desire for a strategic transaction. Despite multiple attempts at direct dialogue with Arrowhead, and in particular due to the poison pill which Arrowhead implemented in March 2017, it became increasingly clear that a transaction would not be possible. As a result, and given the significant rise in the share price of Arrowhead, the Board subsequently treated the near 10% stake as an investment to be liquidated in an orderly manner in order to deploy the capital for our core drug development activities.

Silence is subsequently pleased to state that it has completed the sale of its entire stake in Arrowhead. The common shares originally cost $11.3 million, and net sale proceeds were $24.7 million. The common shares were sold at an average price of $3.64.

After completing the sale of all Arrowhead shares, the Company’s unaudited net cash balance at January 2nd, 2018 was £43 million ($58 million) compared to £29.8 million at 30 June 2017.

Litigation update

As in any novel therapeutic area, Intellectual Property (IP) and Freedom to Operate (FTO) is the foundation of any biotechnology company. In 2017, Silence continued to strengthen its IP estate. The US Patent and Trade Mark Office granted a number of additional US patent applications, providing Silence with further protection for its innovative chemical modification technology in the US. Silence now has ten granted US patents, one US patent application, three granted European patents and four European patent applications encompassing its chemical modification technology.

Silence believes that these newly granted claims are relevant to third-party RNAi medicines and that its foundational IP is essential for the clinical and commercial viability of the RNAi field. The UK litigation with Alnylam Pharmaceuticals is progressing, and it seems likely that all issues between the parties will be heard at a trial beginning on, or around, December 3rd, 2018. Silence intends to vigorously defend its position after many years of invested capital in IP.

Quark

In July 2017, licensee Quark Pharmaceuticals (“Quark”) announced positive results of a Phase 2 trial evaluating the efficacy and safety of an siRNA treatment (QPI-1002) for the prevention of Acute Kidney Injury (AKI) in subjects at high risk following cardiac surgery, utilising Silence’s patented chemical modification technology. Primary and secondary endpoints of the trial were met and supported continued clinical development of the product which is exclusively licensed to Novartis for worldwide development and commercialization in AKI. Novartis also has an option on QPI-1002 in delayed graft function for which a phase 3 study is ongoing. We await news from Quark as to the next steps in the development of QPI-1002 in AKI.

Board and senior management

Since 2016, Silence has been optimising and improving its GalNAC-siRNA based technology as its primary therapeutic toolkit. During this time, there has been a significant drive to recruit key personnel to transition this technology to therapeutic candidates. Silence now has an International, sector-experienced Board and executive team with a strong track record of proven execution and expertise in the RNAi and oligonucleotide fields as well as more general expertise within the pharma and biotech industry. The Company continues to strengthen internal capabilities in clinical development and regulatory affairs as it transitions to a clinical phase Company.

Pipeline update and target selection strategy

The Company had a successful 2017, making important steps in its ambition to transition into a drug development Company. It has continued to see progress in its drug pipeline with plans to file its first GalNAc-siRNA Clinical Trial Application (CTA) for treatment of iron overload disorder by end 2018.

In addition, significant focus is being given to new target selection to enable the company to have a deep pre-clinical pipeline which can undergo clear go/no go gates to potential CTA filings. We have made material investment in this area in terms of highly qualified personnel as we consider it to be key to maximising our platform capability.

Ali Mortazavi, Chief Executive Officer of Silence Therapeutics, commented:

“At our recent Capital Markets Day, Silence demonstrated that it is now has a powerful, reproducible and modular GalNAc-siRNA platform that can rapidly and safely be used to specifically and effectively silence any disease-associated target gene in hepatocytes. With £43 million of cash at the start of 2018, Silence is well positioned to further develop its existing pipeline, as well as adding significant new targets, some incorporating next generation technology. At the same time, we are actively looking to partner our platform and programs, and to enter into both commercial and academic collaborations, strengthening our balance sheet and widening our portfolio. We are highly committed and motivated by the potential of RNAi based therapies using our GalNAc-siRNA technology. We look forward to further progress in 2018 and the future development of a robust pipeline.”

The company will provide further details on 2017 performance at its Preliminary Results in March 2018.

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