SLN-501

Silence also announced positive topline 36-week data from ongoing phase 2 study of zerlasiran in patients with high lipoprotein(a) Company to host conference call and webcast today at 8 a.m. EDT / 12 p.m. GMT LONDON--(BUSINESS WIRE)-- Silence Therapeutics plc, Nasdaq: SLN (“Silence” or “the Company”), an experienced and innovative biotechnology company committed to transforming people’s lives by silencing diseases through precision engineered medicines, today reported its financial results for the full year ended December 31, 2023, and reviewed recent business highlights. “2023 was a year of strong execution across Silence as we advanced our proprietary pipeline in the clinic,” said Craig Tooman, President and CEO of Silence. “That’s clearly bearing fruit today with the positive topline 36-week data we announced from the ongoing phase 2 study of zerlasiran in patients with high Lp(a). We are excited about these data and the potential for zerlasiran to address the needs of up to 1.4 billion worldwide living with high Lp(a). In addition to zerlasiran, we’ve made excellent progress advancing divesiran in PV and remain on-track to report phase 1 data by June. On the partnering side, we were pleased for AstraZeneca to enter the clinic with the first product candidate under our collaboration last month, further highlighting the productivity of our mRNAi GOLD™ platform. We look forward to more clinical data unfolding in the coming year from our proprietary programs and building recognition of Silence as a true platform company.” Recent Business Highlights Zerlasiran for cardiovascular disease In November 2023, reported positive topline data in multiple dose portion of the APOLLO phase 1 study of zerlasiran in patients with high Lp(a). Today announced positive topline 36-week data from the ongoing ALPACAR-360 phase 2 study of zerlasiran in patients with a median baseline Lp(a) of approximately 215 nmol/L. Zerlasiran was administered at 300 mg subcutaneously every 16 or 24 weeks and 450 mg every 24 weeks. Study demonstrated highly significant reductions in Lp(a) compared with placebo to week 36 (primary endpoint) Median percentage reduction in Lp(a) of 90% or greater were observed for both doses at week 36 No new safety concerns were identified during this treatment period The 60-week study is ongoing and secondary endpoints, including change in Lp(a) from baseline to week 48 (end of treatment period), week 60 (end of study) and potential effects on other lipids/lipoproteins, will be evaluated 48-week topline data expected in the second quarter of 2024 Divesiran for hematological diseases Advanced enrollment in the SANRECO phase 1/2 study of divesiran in PV patients. Emerging data from the ongoing phase 1 open label portion of the study continue to look promising On-track to report phase 1 data in the second quarter of 2024 Collaborations In February 2024, achieved a $10 million milestone following the initiation of a phase 1 trial of the first product candidate under AstraZeneca collaboration. In March 2024, Mallinckrodt notified Silence that they will not pursue further development of SLN501 following the completion of the phase 1 clinical trial. This will conclude all activities and commitments under the collaboration agreement. “We ended December 2023 with approximately $68.8 million and significantly increased our cash position in early 2024 to over $200 million,” said Rhonda Hellums, Chief Financial Officer of Silence. “We are excited to have multiple programs advancing in the clinic, supported by a substantial cash position that extends our estimated runway into 2026. We also continue to evaluate partnering opportunities that could provide additional non-dilutive funding and further extend our cash runway. Looking ahead, we remain committed to responsibly investing in initiatives that will advance our pipeline and expand our platform into new targets where there is clear unmet need and opportunity to deliver value to patients.” Financial Highlights for Year End 2023 Cash Position: Cash and cash equivalents of £54.0 million ($68.8 million) as of December 2023, compared with £71.1 million as of December 31, 2022. Collaboration Revenue: Collaboration revenue was £25.4 million for the year ended December 31, 2023, and £17.5 million for the year ended December 31, 2022, and related to research services performed under the collaboration agreements with AstraZeneca, Hansoh and Mallinckrodt. R&D Expenses: Research and development (R&D) expenses were £44.0 million for the year ended December 31, 2023, compared to £35.6 million for the year ended December 31, 2022. The increase is a result of additional clinical studies and an increase in contract manufacturing activities for Silence’s proprietary programs. G&A Expenses: General and administrative (G&A) expenses were £20.6 million for the year ended December 31, 2023, compared to £19.6 million for the year ended December 31, 2022. The increase is primarily due to non-cash stock compensation costs. Net Loss: Net loss was £43.3 million, or 38.9 pence basic and diluted net loss per share for the year ended December 31, 2023, compared to a net loss of £40.5 million, or 41.9 pence basic and diluted net loss per share for the year ended December 31, 2022. Post-Period Financial Highlights In January 2024, received total proceeds of approximately $30 million (includes approximately $20 million from ADS sales under Silence’s Sales Agreement and approximately $10 million in R&D tax credit). In February 2024, announced a private placement of ADSs with gross proceeds of approximately $120 million (£94.5 million). In February 2024, achieved a $10 million clinical milestone under AstraZeneca collaboration. This will be received in April 2024. Total ADSs outstanding were approximately 46,502,272, as of March 1, 2024. Cash and Liquidity Update As of December 31, 2023, we had cash and cash equivalents of £54.0 million ($68.8 million). With the addition of gross proceeds from our private placement in February 2024 of $120 million (approximately £94.4 million) before deducting fees and estimated offering expenses, the $30 million from proceeds from sale of ADSs under our ATM and receipt of our UK R&D tax credit, and the receipt of the AstraZeneca $10 million milestone in the second quarter of 2024, we believe that our cash of over $200 million and anticipated milestones from current collaborations will be sufficient to fund our operating expenses and capital expenditure requirements into 2026. We may also achieve further milestones from our current collaboration partners which will further extend our cash runway. Conference Call & Webcast Details Company management will host a conference call and webcast today, Wednesday, March 13, 2024, at 8 a.m. EDT / 12:00 p.m. GMT. Webcast link: Conference call registration link: The conference call and webcast will also be archived on the Company’s website at . About Silence Therapeutics Silence Therapeutics is developing a new generation of medicines by harnessing the body's natural mechanism of RNA interference, or RNAi, to inhibit the expression of specific target genes thought to play a role in the pathology of diseases with significant unmet need. Silence's proprietary mRNAi GOLD™ platform can be used to create siRNAs (short interfering RNAs) that precisely target and silence disease-associated genes in the liver, which represents a substantial opportunity. Silence's wholly owned product candidates include zerlasiran (SLN360) designed to address the high and prevalent unmet medical need in reducing cardiovascular risk in people born with high levels of lipoprotein(a) and divesiran (SLN124) designed to address hematological diseases. Silence also maintains ongoing research and development collaborations with AstraZeneca and Hansoh Pharma, among others. For more information, please visit . Forward-Looking Statements Certain statements made in this announcement are forward-looking statements within the meaning of the U.S. Private Securities Litigation Reform Act of 1995 and other securities laws, including with respect to the Company’s cash runway and forecast operating cash flow, the Company’s clinical and commercial prospects, regulatory approvals of the Company’s product candidates, potential partnerships or collaborations or payments under new and existing collaborations, the initiation or completion of the Company’s clinical trials and the anticipated timing or outcomes of data reports from the Company’s clinical trials. These forward-looking statements are not historical facts but rather are based on the Company's current assumptions, beliefs, expectations, estimates and projections about its industry. Words such as “anticipate,” “expect,” “intend,” “plan,” “believe,” “seek,” “estimate,” and similar expressions are intended to identify forward-looking statements. These statements are not guarantees of future performance and are subject to known and unknown risks, uncertainties, and other factors, some of which are beyond the Company's control, are difficult to predict, and could cause actual results to differ materially from those expressed or forecasted in the forward-looking statements, including those risks identified in the Company’s most recent Admission Document and its Annual Report on Form 20-F filed with the U.S. Securities and Exchange Commission on the date hereof. The Company cautions security holders and prospective security holders not to place undue reliance on these forward-looking statements, which reflect the view of the Company only as of the date of this announcement. The forward-looking statements made in this announcement relate only to events as of the date on which the statements are made. The Company will not undertake any obligation to release publicly any revisions or updates to these forward-looking statements to reflect events, circumstances, or unanticipated events occurring after the date of this announcement except as required by law or by any appropriate regulatory authority. SILENCE THERAPEUTICS plc CONSOLIDATED INCOME STATEMENTS (in thousands, except for loss per share) 2023 2022 2021 £000s £000s £000s Revenue 25,375 17,501 12,415 Cost of sales (10,318 ) (10,880 ) (7,456 ) Gross profit 15,057 6,621 4,959 Research and development costs (44,025 ) (35,605 ) (30,765 ) General and administrative expenses (20,636 ) (19,609 ) (20,008 ) Operating loss (49,604 ) (48,593 ) (45,814 ) Finance and other expenses (2,152 ) (47 ) (52 ) Finance and other income 1,446 1,272 10 Loss for the year before taxation (50,310 ) (47,368 ) (45,856 ) Taxation 7,043 6,879 6,446 Loss for the year after taxation (43,267 ) (40,489 ) (39,410 ) Loss per ordinary equity share (basic and diluted) (38.9) pence (41.9) pence (44.3) pence SILENCE THERAPEUTICS plc CONSOLIDATED BALANCE SHEETS (in thousands) December 31, 2023 2022 £000s £000s Non-current assets Property, plant and equipment 1,813 2,201 Goodwill 7,840 8,009 Other intangible assets 284 320 Other long term assets 2,580 Financial assets at amortized cost 284 284 12,801 10,814 Current assets Cash and cash equivalents 54,031 54,816 Financial assets at amortized cost - 16,328 R&D tax credit receivable 17,627 14,882 Other current assets 9,135 9,745 Trade receivables 228 915 81,021 96,686 Non-current liabilities Contract liabilities (58,910 ) (63,485 ) Lease liability (93 ) - (59,003 ) (63,485 ) Current liabilities Contract liabilities (5,161 ) (8,864 ) Trade and other payables (12,429 ) (12,633 ) Lease liability (179 ) (446 ) (17,769 ) (21,943 ) Net assets 17,050 22,072 Capital and reserves attributable to the owners of the parent Share capital 5,942 5,390 Capital reserves 313,769 277,860 Translation reserve 1,951 2,085 Accumulated losses (304,612 ) (263,263 ) Total shareholders equity 17,050 22,072

LONDON--(BUSINESS WIRE)-- Silence Therapeutics plc, Nasdaq: SLN (“Silence” or “the Company”), an experienced and innovative biotechnology company committed to transforming people’s lives by silencing diseases through precision engineered medicines, today reported its financial results for the first quarter ended March 31, 2023 and reviewed recent business highlights. “2023 has been marked by strong execution across all areas of our business,” said Craig Tooman, President and Chief Executive Officer at Silence. “We completed enrollment in the zerlasiran phase 2 study in four months which exceeded expectations, advanced SLN124 in the clinic and expanded our wholly owned pipeline with two very promising complement assets. We also made great headway with our partnered programs, including the achievement of a key milestone which will result in a $10 million payment in our AstraZeneca collaboration. Our technology is increasingly being recognized as a platform and we expect this to continue along with our clinical advancement.” First Quarter 2023 and Recent Business Highlights mRNAi GOLD™ Proprietary Program Updates zerlasiran (cardiovascular disease) In January 2023, we initiated the ALPACAR-360 phase 2 study in subjects with atherosclerotic cardiovascular disease (“ASCVD”) and high lipoprotein(a) (“Lp(a)”). In May 2023, we announced complete enrollment in the ALPACAR-360 phase 2 study. We expect to report topline data in mid-2024. In April 2023, we completed dosing in the multiple dose portion of the APOLLO phase 1 study in subjects with stable ASCVD and high Lp(a). We remain on-track to report topline data in the fourth quarter of 2023. SLN124 (hematological disorders) In January 2023, we initiated the SANRECO phase 1/2 study in patients with polycythemia vera (“PV”). In March 2023, we completed dosing in the multiple dose portion of the GEMINI II phase 1 study in thalassemia patients. We remain on-track to report topline data in the fourth quarter of 2023. mRNAi GOLD™ Partnered Program Updates In March 2023, we acquired back exclusive worldwide rights to two preclinical siRNA assets under our Mallinckrodt collaboration for complement-mediated diseases. Under the terms of the agreement, Silence did not make any upfront payment and Mallinckrodt is eligible to receive future success-based milestones and low single digit royalties on net sales if the projects advance. SLN501, the C3 targeting program, remains under the original collaboration agreement. In May 2023, we achieved a $10.0 million milestone payment from AstraZeneca following the nomination of the first product candidate under our siRNA (“short interfering RNA”) collaboration focused on cardiovascular, renal, metabolic and respiratory diseases. “We remain committed to responsibly investing in our pipeline and on initiatives where we see high value potential,” said Rhonda Hellums, Chief Financial Officer at Silence. “We ended March with approximately $77.8 million in cash and cash equivalents. In May, we achieved a $10 million milestone from our AstraZeneca collaboration, and we expect to receive additional non-dilutive capital from our existing partnerships, which we believe will further extend our cash runway beyond the zerlasiran phase 2 data readout.” First Quarter 2023 Financial Results For the three-month period ending March 31, 2023, the net loss after tax was £10.2 million, or weighted average loss per share of 9.5 pence, compared to £7.7 million, or weighted average loss per share of 8.6 pence, for the same period in 2022. The increase in net loss was primarily related to increased research and development spend offset by an increase in revenues from our collaboration agreements as we achieved an additional milestone and continue to further advance the programs. Revenue Revenue recognized for the quarter ending March 31, 2023 was £11.4 million, compared to £5.7 million for the quarter ending March 31, 2022. The Company records revenue from collaborations based on percentage of contract completion and the increase was primarily a result of our Mallinckrodt collaboration in which we reacquired exclusive worldwide rights to two preclinical siRNA assets. This resulted in a modification of the agreement triggering additional revenue recognized. Cost of sales The cost of sales increased for the three months ending March 31, 2023 to £4.5 million from £2.3 million in the period ending March 31, 2022. Cost of sales includes research and development expenditure that is directly related to work carried out on revenue-generating contracts. The increase was largely due to the further advancement of collaboration programs. Research and Development During the period, research and development expenditures were £12.5 million compared to £7.6 million for the same three-month period ending March 31, 2022. This was largely due to an increase in contracted research and development expenses of £4.2 million resulting from advancement of the studies for SLN124 and zerlasiran compared to the corresponding three-month period in the prior year. General and Administrative General and administrative expenses increased by £0.7 million to £6.5 million for the three-month period ending March 31, 2023 from £5.8 million for the corresponding period in 2022. This increase was predominantly related to increased personnel costs related to equity-based compensation. Liquidity, cash and cash equivalents As of March 31, 2023, the Company had £62.9 million of cash and cash equivalents, and U.S. Treasury Bills or approximately $77.8 million. We believe that our current cash, cash equivalents and U.S. Treasury Bills, as well as the receipt of the $10 million milestone achieved in May 2023 and anticipated additional future milestone payments of up to $14 million from existing collaboration agreements will extend the ability to fund operations through the third quarter of 2024. About Silence Therapeutics Silence Therapeutics is developing a new generation of medicines by harnessing the body's natural mechanism of RNA interference, or RNAi, to inhibit the expression of specific target genes thought to play a role in the pathology of diseases with significant unmet need. Silence's proprietary mRNAi GOLD™ platform can be used to create siRNAs (short interfering RNAs) that precisely target and silence disease-associated genes in the liver, which represents a substantial opportunity. Silence's wholly owned product candidates include zerlasiran designed to address the high and prevalent unmet medical need in reducing cardiovascular risk in people born with high levels of lipoprotein(a) and SLN124 designed to address hematological diseases. Silence also maintains ongoing research and development collaborations with AstraZeneca, Mallinckrodt Pharmaceuticals, and Hansoh Pharma, among others. For more information, please visit . Forward-Looking Statements Certain statements made in this announcement are forward-looking statements within the meaning of the U.S. Private Securities Litigation Reform Act of 1995 and other securities laws, including with respect to the Company’s cash runway and forecast operating cash flow, the Company’s clinical and commercial prospects, regulatory approvals of the Company’s product candidates, potential partnerships or collaborations or payments under new and existing collaborations, the initiation or completion of the Company’s clinical trials and the anticipated timing or outcomes of data reports from the Company’s clinical trials. These forward-looking statements are not historical facts but rather are based on the Company's current assumptions, beliefs, expectations, estimates and projections about its industry. Words such as “anticipate,” “expect,” “intend,” “plan,” “believe,” “seek,” “estimate,” and similar expressions are intended to identify forward-looking statements. These statements are not guarantees of future performance and are subject to known and unknown risks, uncertainties, and other factors, some of which are beyond the Company's control, are difficult to predict, and could cause actual results to differ materially from those expressed or forecasted in the forward-looking statements, including those risks identified in the Company’s most recent Admission Document and its Annual Report on Form 20-F filed with the U.S. Securities and Exchange Commission on March 15, 2023. The Company cautions security holders and prospective security holders not to place undue reliance on these forward-looking statements, which reflect the view of the Company only as of the date of this announcement. The forward-looking statements made in this announcement relate only to events as of the date on which the statements are made. The Company will not undertake any obligation to release publicly any revisions or updates to these forward-looking statements to reflect events, circumstances, or unanticipated events occurring after the date of this announcement except as required by law or by any appropriate regulatory authority. Condensed consolidated income statement (unaudited) Three months ended Three months ended March 31, 2023 March 31, 2022 £000s (except per share information) '£000s '£000s Revenue 11,374 5,722 Cost of sales (4,534 ) (2,275 ) Gross profit 6,840 3,447 Research and development costs (12,539 ) (7,603 ) General and administrative expenses (6,450 ) (5,766 ) Operating loss (12,149 ) (9,922 ) Finance and other expenses (860 ) - Finance and other income 336 350 Loss for the period before taxation (12,673 ) (9,572 ) Taxation 2,469 1,888 Loss for the period after taxation (10,204 ) (7,684 ) Loss per ordinary equity share (basic and diluted) (9.5) pence (8.6) pence Condensed consolidated balance sheet (unaudited) March 31, 2023 December 31, 2022 £000s £000s Non-current assets Property, plant and equipment 2,101 2,201 Goodwill 7,962 8,009 Other intangible assets 310 320 Financial assets at amortized cost 284 284 10,657 10,814 Current assets Cash and cash equivalents 46,731 54,816 Financial assets at amortized cost 16,135 16,328 R&D tax credit receivable 10,736 14,882 Other current assets 8,385 9,745 Trade receivables 1,693 915 83,680 96,686 Non-current liabilities Contract liabilities (59,765 ) (63,485 ) Lease liability (218 ) - (59,983 ) (63,485 ) Current liabilities Contract liabilities (4,338 ) (8,864 ) Trade and other payables (13,246 ) (12,633 ) Lease liability (180 ) (446 ) (17,764 ) (21,943 ) Net assets 16,590 22,072 Capital and reserves attributable to the owners of the parent Share capital 5,403 5,390 Capital reserves 281,552 277,860 Translation reserve 2,046 2,085 Accumulated losses (272,411 ) (263,263 ) Total shareholders equity 16,590 22,072