We use cookies to understand how you use our site and to improve your experience.
This includes personalizing content and advertising.
By pressing "Accept All" or closing out of this banner, you consent to the use of all cookies and similar technologies and the sharing of information they collect with third parties.
You can reject marketing cookies by pressing "Deny Optional," but we still use essential, performance, and functional cookies.
In addition, whether you "Accept All," Deny Optional," click the X or otherwise continue to use the site, you accept our Privacy Policy and Terms of Service, revised from time to time.
You are being directed to ZacksTrade, a division of LBMZ Securities and licensed broker-dealer. ZacksTrade and Zacks.com are separate companies. The web link between the two companies is not a solicitation or offer to invest in a particular security or type of security. ZacksTrade does not endorse or adopt any particular investment strategy, any analyst opinion/rating/report or any approach to evaluating individual securities.
If you wish to go to ZacksTrade, click OK. If you do not, click Cancel.
PRTA Dives 53.5% YTD: Will the Restructuring Effort Boost Prospects?
Read MoreHide Full Article
Key Takeaways
PRTA discontinued birtamimab after it failed to meet endpoints in the phase III AFFIRM-AL study.
The company will slash 63% of its workforce and now expects a 2025 net loss of $240 to $248 million.
Roche will move prasinezumab into phase III, potentially triggering milestones and royalties for PRTA.
Shares of Prothena Corporation (PRTA - Free Report) plummeted 53.5% year to date compared with the industry’s decline of 0.6%.
The recent pipeline setbacks have significantly hurt PRTA’s growth prospects.
Image Source: Zacks Investment Research
Last month, PRTA announced that it is reducing its workforce by 63% to lower its operating costs, essential to support its remaining wholly owned programs, its obligations to partnered programs and its anticipated business development activities.
As a result of this restructuring, PRTA also revised its annual guidance. The company expects its 2025 net cash burn from operating and investing activities to be in the range of $170- $178 million. PRTA expects approximately $298 million (midpoint) in cash, cash equivalents and restricted cash. Net loss is now estimated between $240 million and $248 million (previous guidance: $197-$205 million).
The estimated loss for 2025 includes $105-$110 million of operating expenses associated with birtamimab and the company's reorganization, including research, development, manufacturing and pre-commercial expenses, severance costs and contract termination fees related to manufacturing obligations, and approximately $12 million of non-cash share-based compensation expense.
PRTA expects the discontinuation of birtamimab development will result in an approximate decrease of $96 million (midpoint) in annualized net cash burn.
Recent Pipeline Setbacks Hurt PRTA Stock
In May 2025, PRTA announced the discontinuation of the development of the pipeline candidate, birtamimab.
The decision to discontinue comes after the late-stage AFFIRM-AL clinical study evaluating birtamimab in patients with AL amyloidosis did not meet its primary endpoint. Birtamimab was a wholly-owned potential best-in-class anti-amyloid antibody for the treatment of AL amyloidosis.
The phase III AFFIRM-AL study was a global, double-blind, placebo-controlled, time-to-event clinical trial that enrolled 207 newly diagnosed, treatment naïve patients with Mayo Stage IV AL amyloidosis. However, the primary endpoint of time to all-cause mortality was not met for patients treated with birtamimab. In addition, neither of the secondary endpoints were met: six-minute walk test distance and Short Form-36 version 2 Physical Component Score. Nonetheless, birtamimab was generally safe and well-tolerated, consistent with its established safety profile.
What’s Next for PRTA?
In June 2025, partner Roche (RHHBY - Free Report) announced that it will advance pipeline candidate prasinezumab into phase III development for early-stage Parkinson’s disease. The decision to advance prasinezumab to late-stage development was based on data from the phase IIb PADOVA study and ongoing open-label extensions (OLEs) of PADOVA and phase II PASADENA studies.
RHHBY’s decision to advance the candidate despite mixed data bodes well for PRTA.
Roche has the sole responsibility for developing and commercializing prasinezumab and will pay double-digit teen royalties on net sales of the candidate to Prothena. To date, PRTA has earned $135 million with up to $620 million in additional milestone payments that include regulatory and sales milestones. In addition, Prothena has the option to co-promote prasinezumab in the United States.
PRTA expects initial data in August from a phase I study, ASCENT, on its wholly owned PRX012 program in Alzheimer’s disease.
Partner Novo Nordisk (NVO - Free Report) is evaluating Coramitug (formerly PRX004), a potential first-in-class amyloid depleter antibody for the treatment of ATTR amyloidosis with cardiomyopathy.
NVO is conducting an ongoing phase II study in patients with ATTR cardiomyopathy and expects to share data in the second half of 2025.
PRTA is advancing an early-stage pipeline of programs for several potential neurological indications with Bristol Myers (BMY - Free Report) .
BMS-986446 is a best-in-class anti-tau, MTBR-specific antibody that is being investigated for the potential treatment of AD.
Bristol Myers continues to enroll patients with early AD in the ongoing phase II study on BMS-986446. The study is expected to be completed in 2027.
PRX019, a potential treatment for neurodegenerative diseases, is also being developed in collaboration with BMY.
PRTA has initiated a phase I first-in-human clinical trial on PRX019 to evaluate the safety, tolerability, immunogenicity and pharmacokinetics of single ascending and multiple doses in healthy adults. The phase I study is expected to be completed in 2026.
PRTA expects to receive up to $105 million in 2026 in clinical milestones from various partnered programs.
Image: Bigstock
PRTA Dives 53.5% YTD: Will the Restructuring Effort Boost Prospects?
Key Takeaways
Shares of Prothena Corporation (PRTA - Free Report) plummeted 53.5% year to date compared with the industry’s decline of 0.6%.
The recent pipeline setbacks have significantly hurt PRTA’s growth prospects.
Image Source: Zacks Investment Research
Last month, PRTA announced that it is reducing its workforce by 63% to lower its operating costs, essential to support its remaining wholly owned programs, its obligations to partnered programs and its anticipated business development activities.
As a result of this restructuring, PRTA also revised its annual guidance. The company expects its 2025 net cash burn from operating and investing activities to be in the range of $170- $178 million. PRTA expects approximately $298 million (midpoint) in cash, cash equivalents and restricted cash. Net loss is now estimated between $240 million and $248 million (previous guidance: $197-$205 million).
The estimated loss for 2025 includes $105-$110 million of operating expenses associated with birtamimab and the company's reorganization, including research, development, manufacturing and pre-commercial expenses, severance costs and contract termination fees related to manufacturing obligations, and approximately $12 million of non-cash share-based compensation expense.
PRTA expects the discontinuation of birtamimab development will result in an approximate decrease of $96 million (midpoint) in annualized net cash burn.
Recent Pipeline Setbacks Hurt PRTA Stock
In May 2025, PRTA announced the discontinuation of the development of the pipeline candidate, birtamimab.
The decision to discontinue comes after the late-stage AFFIRM-AL clinical study evaluating birtamimab in patients with AL amyloidosis did not meet its primary endpoint. Birtamimab was a wholly-owned potential best-in-class anti-amyloid antibody for the treatment of AL amyloidosis.
The phase III AFFIRM-AL study was a global, double-blind, placebo-controlled, time-to-event clinical trial that enrolled 207 newly diagnosed, treatment naïve patients with Mayo Stage IV AL amyloidosis. However, the primary endpoint of time to all-cause mortality was not met for patients treated with birtamimab. In addition, neither of the secondary endpoints were met: six-minute walk test distance and Short Form-36 version 2 Physical Component Score. Nonetheless, birtamimab was generally safe and well-tolerated, consistent with its established safety profile.
What’s Next for PRTA?
In June 2025, partner Roche (RHHBY - Free Report) announced that it will advance pipeline candidate prasinezumab into phase III development for early-stage Parkinson’s disease. The decision to advance prasinezumab to late-stage development was based on data from the phase IIb PADOVA study and ongoing open-label extensions (OLEs) of PADOVA and phase II PASADENA studies.
RHHBY’s decision to advance the candidate despite mixed data bodes well for PRTA.
Roche has the sole responsibility for developing and commercializing prasinezumab and will pay double-digit teen royalties on net sales of the candidate to Prothena. To date, PRTA has earned $135 million with up to $620 million in additional milestone payments that include regulatory and sales milestones. In addition, Prothena has the option to co-promote prasinezumab in the United States.
PRTA expects initial data in August from a phase I study, ASCENT, on its wholly owned PRX012 program in Alzheimer’s disease.
Partner Novo Nordisk (NVO - Free Report) is evaluating Coramitug (formerly PRX004), a potential first-in-class amyloid depleter antibody for the treatment of ATTR amyloidosis with cardiomyopathy.
NVO is conducting an ongoing phase II study in patients with ATTR cardiomyopathy and expects to share data in the second half of 2025.
PRTA is advancing an early-stage pipeline of programs for several potential neurological indications with Bristol Myers (BMY - Free Report) .
BMS-986446 is a best-in-class anti-tau, MTBR-specific antibody that is being investigated for the potential treatment of AD.
Bristol Myers continues to enroll patients with early AD in the ongoing phase II study on BMS-986446. The study is expected to be completed in 2027.
PRX019, a potential treatment for neurodegenerative diseases, is also being developed in collaboration with BMY.
PRTA has initiated a phase I first-in-human clinical trial on PRX019 to evaluate the safety, tolerability, immunogenicity and pharmacokinetics of single ascending and multiple doses in healthy adults. The phase I study is expected to be completed in 2026.
PRTA expects to receive up to $105 million in 2026 in clinical milestones from various partnered programs.
PRTA currently carries a Zacks Rank #3 (Hold). You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.