GlobeNewswire Inc | Nov 4, 2020 04:06PM EST

November 04, 2020

-- Net cash used in operating and investing activities was $19.5 millionin the third quarter and $61.4 million for the first nine months of 2020; quarter-end cash and restricted cash position of $317.2 million provides funding to advance the R&D pipeline -- Roche presented results from the Phase 2 PASADENA study of prasinezumab in patients with early Parkinsons disease in an oral top abstract presentation at MDS Congress 2020 -- Announced that Roche and Prothena will advance prasinezumab into late-stage clinical development -- Presented new preclinical data from two Alzheimers disease programs at CTAD 2020

DUBLIN, Ireland, Nov. 04, 2020 (GLOBE NEWSWIRE) -- Prothena Corporation plc (NASDAQ:PRTA), a late-stage clinical company with expertise in protein dysregulation and a diverse pipeline of investigational therapeutics for neurodegenerative and rare peripheral amyloid diseases, today reported financial results for the third quarter and first nine months of 2020. In addition, the Company provided an update on its R&D programs.

During the third quarter, Roche presented data from the Phase 2 PASADENA study of prasinezumab in patients with early Parkinsons disease that demonstrated signals of efficacy consistent with disease modification and recently, we announced that prasinezumab will advance into a late-stage study, said Gene Kinney, Ph.D., President and Chief Executive Officer of Prothena. Moving into the fourth quarter, we are building on this momentum with two new data presentations from our Alzheimers disease portfolio at CTAD 2020 this week and additional data from our Phase 1 study of PRX004 in ATTR amyloidosis is expected later this quarter. Looking ahead, we remain focused on advancing our R&D pipeline towards key milestones.

Third Quarter and Recent Highlights

-- Announced results from the Phase 2 PASADENA study of prasinezumab in patients with early Parkinsons disease that were presented by Roche at the International Parkinson and Movement Disorder Societys MDS Virtual Congress 2020 (MDS Congress 2020) on September 15, 2020. Prasinezumab is the first potentially disease-modifying, anti-alpha-synuclein antibody to demonstrate signs of efficacy on multiple pre-specified secondary and exploratory clinical endpoints in patients with early Parkinsons disease. In the study, prasinezumab significantly reduced decline in motor function by 35% (pooled dose levels) vs. placebo after one year of treatment on the centrally rated assessment of Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III, a clinical examination of motor function. Prasinezumab-treated patients also demonstrated a significant delay in time to clinically meaningful worsening of motor progression on the site rated assessment of time to at least a 5-point progression on MDS-UPDRS Part III vs. placebo over one year, with a hazard ratio of 0.82 (pooled dose levels). -- Announced that Roche and Prothena will advance prasinezumab into a late-stage (Phase 2b) study in patients with early Parkinsons disease. The study will be designed to further assess the efficacy of prasinezumab by expanding upon the patient population enrolled in PASADENA to include patients with early Parkinsons disease on stable levodopa therapy. -- Presented preclinical data from two programs in its Alzheimers disease portfolio at the 13th Clinical Trials on Alzheimers Disease Conference 2020 (CTAD 2020). First, a next generation anti- A antibody, PRX012, for more convenient subcutaneous administration to improve patient access. Second, a multi-immunogen vaccine that targets both A and Tau, two main pathological hallmarks of Alzheimers disease, for the prevention and treatment of Alzheimers disease.

Upcoming Research and Development Milestones

Prasinezumab (PRX002/RG7935), a potential treatment for Parkinsons disease,is a monoclonal antibody designed to target alpha-synuclein and is the focus of the worldwide collaboration with Roche

-- Part 2 of the Phase 2 PASADENA study (a 52-week blinded extension phase) is ongoing. -- Prothena will earn a $60 million clinical milestone payment upon the first patient dosed in the Phase 2b study. Further details are expected to be announced in the first half of 2021.

PRX004, a potential treatment for ATTR amyloidosis, is a monoclonal antibody designed to deplete the pathogenic, non-native forms of the TTR protein

-- Prothena expects to report new data in fourth quarter of this year from the dose-escalation and available LTE portion of the study. -- Prothena continues to believe that the study has advanced sufficiently to determine next steps for the program and has begun further clinical development planning for next clinical studies in patients with moderate-to-advanced ATTR cardiomyopathy (ATTR-CM). Current therapies have not demonstrated efficacy in these patients who are at high risk of early mortality.

Discovery and Preclinical Development Prothena is advancing an early-stage pipeline of programs for a number of potential neurological indications

-- Prothena continues to expect to advance IND-enabling activities in 2020 for PRX005, our preclinical tau program, part of a global neuroscience collaboration with Bristol-Myers Squibb, and expects to file an IND in 2021. -- Prothena has initiated IND-enabling studies for PRX012, our preclinical A program, and expects to file an IND in 2021.

Upcoming Investor Conferences

Members of the senior management team will present and participate in investor meetings at the following upcoming investor conferences:

-- Stifel 2020 Virtual Healthcare Conference on Tuesday November 17, 2020 at 4:00 PM Eastern Time -- Jefferies Virtual London Healthcare Conference on Thursday November 19, 2020 at 2:55 PM Eastern Time

A live webcast of the presentations can be accessed through the Investors section of the Company's website at www.prothena.com. Following the live presentations, a replay of the webcast will be available on the Company's website for at least 90 days following the presentation date.

Third Quarter and First Nine Months of 2020 Financial Results

For the third quarter and first nine months of 2020, Prothena reported a net loss of $30.6 million and $80.4 million, respectively, as compared to a net loss of $19.4 million and $56.1 million for the third quarter and first nine months of 2019, respectively. The third quarter and first nine months of 2019 included a restructuring credit of nil and $0.1 million, respectively, which resulted from an adjustment in previously recorded employee termination benefits associated with the discontinuation of the NEOD001 program. Net loss per share for the third quarter and first nine months of 2020 was $0.77 and $2.02, respectively, as compared to a net loss per share of $0.49 and $1.41 for the third quarter and first nine months of 2019, respectively.

Prothena reported total revenue, primarily from its collaboration with Roche, of $0.2 million and $0.5 million for the third quarter and first nine months of 2020, respectively as compared to total revenue of $0.2 million and $0.6 million for the third quarter and first nine months of 2019, respectively.

Research and development (R&D) expenses totaled $21.6 million and $54.1 million for the third quarter and first nine months of 2020, respectively, as compared to $12.5 million and $35.4 million for the third quarter and first nine months of 2019, respectively. The increase in R&D expense for the third quarter and first nine months of 2020 compared to the same periods in the prior year was primarily due to higher manufacturing costs, higher collaboration expense with Roche related to the prasinezumab program and higher R&D consulting expense. R&D expenses included non-cash share-based compensation expense of $2.1 million and $6.2 million for the third quarter and first nine months of 2020, respectively, as compared to $2.0 million and $6.2 million for the third quarter and first nine months of 2019, respectively.

General and administrative (G&A) expenses totaled $9.4 million and $28.8 million for the third quarter and first nine months of 2020, respectively, as compared to $8.7 million and $27.7 million for the third quarter and first nine months of 2019, respectively. The increase in G&A expenses for the third quarter and first nine months of 2020 compared to the same periods in the prior year was primarily related to higher costs for our director and officer insurance premiums offset in part by lower share-based compensation expense. G&A expenses included non-cash share-based compensation expense of $3.5 million and $10.6 million for the third quarter and first nine months of 2020, respectively, as compared to $3.9 million and $12.1 million for the third quarter and first nine months of 2019, respectively.

Total non-cash share-based compensation expense was $5.6 million and $16.8 million for the third quarter and first nine months of 2020, respectively, as compared to $5.8 million and $18.3 million for the third quarter and first nine months of 2019, respectively.

As of September30, 2020, Prothena had $317.2 million in cash, cash equivalents and restricted cash and no debt.

As of October30, 2020, Prothena had approximately 39.9 million ordinary shares outstanding.

The Company continues to expect its full year 2020 net cash burn from operating and investing activities to be $75-$85 million and expects to end the year with approximately $299 million in cash, cash equivalents and restricted cash (midpoint). The estimated full year 2020 net cash burn from operating and investing activities is primarily driven by estimated net loss of $101-$118 million, which includes an estimated $23 million of non-cash share-based compensation expense.

Inducement Grant Under NASDAQ Listing Rule 5635(C)(4)

In connection with hiring two new employees, the compensation committee of the Companys board of directors granted the individuals hired by the Company, in the aggregate, options to purchase 90,000 ordinary shares of the Company. The options have an exercise price per share equal to $11.03, which was the closing trading price on November 2, 2020, the date of the grants. The inducement awards will vest over four years, with 25% of the underlying shares vesting on the one-year anniversary of the date of grants and 1/48th of the underlying shares vesting monthly thereafter over 36 months. The options were granted pursuant to the Companys 2020 Employment Inducement Incentive Plan, which was approved by the Companys board of directors under Rule 5635(c)(4) of The Nasdaq Global Market for equity grants to induce new employees to enter into employment with the Company.

About ProthenaProthena Corporation plc is a late-stage clinical company with expertise in protein dysregulation and a diverse pipeline of novel investigational therapeutics with the potential to change the course of devastating neurodegenerative and rare peripheral amyloid diseases. Fueled by its deep scientific expertise built over decades of research, Prothena is advancing a pipeline of therapeutic candidates for a number of indications and novel targets for which its ability to integrate scientific insights around neurological dysfunction and the biology of misfolded proteins can be leveraged. Prothenas partnered programs include prasinezumab (PRX002/RG7935), in collaboration with Roche for the potential treatment of Parkinsons disease and other related synucleinopathies, and programs that target tau (PRX005), TDP-43, and an undisclosed target in collaboration with Bristol-Myers Squibb for the potential treatment of Alzheimers disease, amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD) or other neurodegenerative diseases. Prothenas proprietary programs include PRX004 for the potential treatment of ATTR amyloidosis, and a portfolio of programs for the potential treatment of Alzheimers disease including PRX012 that targets A (Amyloid beta). For more information, please visit the Companys website at www.prothena.com and follow the Company on Twitter @ProthenaCorp.

Forward-looking Statements

This press release contains forward-looking statements. These statements relate to, among other things, the sufficiency of our cash position to fund advancement of a broad pipeline; the treatment potential and proposed mechanisms of action of prasinezumab, PRX004, PRX005 and PRX012; plans for the ongoing Phase 2 clinical study of prasinezumab and the Phase 1 clinical study of PRX004; the expected timing of reporting data from the Phase 1 clinical study of PRX004; plans for future clinical studies of prasinezumab and PRX004; amounts we might receive under our collaboration with Roche; the continued advancement of our discovery and preclinical pipeline; the timing of IND-enabling activities from our tau andAprograms; our anticipated net cash burn from operating and investing activities for 2020 and expected cash balance at the end of 2020; and our estimated net loss and non-cash share-based compensation expense for 2020. These statements are based on estimates, projections and assumptions that may prove not to be accurate, and actual results could differ materially from those anticipated due to known and unknown risks, uncertainties and other factors, including but not limited to the effects on our business of the worldwide COVID-19 pandemic and the risks, uncertainties and other factors described in the Risk Factors sections of our Annual Report on Form 10-K filed with theSecurities and Exchange Commission(SEC) onMarch 3, 2020, as well as discussions of potential risks, uncertainties, and other important factors in our subsequent filings with theSEC.Prothenaundertakes no obligation to update publicly any forward-looking statements contained in this press release as a result of new information, future events or changes in Prothenas expectations.

PROTHENA CORPORATION PLCCONSOLIDATED STATEMENTS OF OPERATIONS(unaudited - amounts in thousands except per share data)

Three months ended September Nine Months Ended September 30, 30, 2020 2019 2020 2019Collaboration $ 157 $ 205 $ 443 $ 558 revenueLicense revenue ? ? 50 ? Total revenue 157 205 493 558 Operating expenses:Research and 21,605 12,486 54,124 35,365 developmentGeneral and 9,398 8,691 28,795 27,677 administrativeRestructuring ? ? ? (61 ) creditsTotal operating 31,003 21,177 82,919 62,981 expensesLoss from (30,846 ) (20,972 ) (82,426 ) (62,423 ) operationsOther income, 54 1,992 1,362 6,810 netLoss before (30,792 ) (18,980 ) (81,064 ) (55,613 ) income taxesProvision for(benefit from) (215 ) 468 (636 ) 510 income taxesNet loss $ (30,577 ) $ (19,448 ) $ (80,428 ) $ (56,123 ) Basic anddiluted net $ (0.77 ) $ (0.49 ) $ (2.02 ) $ (1.41 ) loss per shareShares used tocompute basic 39,917 39,897 39,912 39,877 and diluted netloss per share

PROTHENA CORPORATION PLCCONSOLIDATED BALANCE SHEETS(unaudited - amounts in thousands)

September 30, December 31, 2020 2019Assets Cash and cash equivalents $ 314,525 $ 375,723 Accounts receivable 22 68 Prepaid expenses and other current assets 4,586 2,584 Restricted cash, current 1,352 ? Total current assets 320,485 378,375 Property and equipment, net 2,899 3,874 Operating lease right-of-use assets 19,197 23,274 Restricted cash, non-current 1,352 2,704 Other non-current assets 11,851 11,041 Total non-current assets 35,299 40,893 Total assets $ 355,784 $ 419,268 Liabilities and Shareholders? Equity Accrued research and development $ 7,617 $ 5,826 Lease liability, current 5,408 5,101 Other current liabilities 8,697 6,787 Total current liabilities 21,722 17,714 Deferred revenue, non current 110,242 110,242 Lease liability, non-current 13,753 17,838 Other non-current liabilities 553 553 Total non-current liabilities 124,548 128,633 Total liabilities 146,270 146,347 Total shareholders? equity 209,514 272,921 Total liabilities and shareholders? equity $ 355,784 $ 419,268

Contacts:

MediaEllen Rose, Head of Communications650-922-2405, ellen.rose@prothena.com

InvestorsJennifer Zibuda, Director, Investor Relations & Communications650-837-8535, jennifer.zibuda@prothena.com