Prothena Q3 Earnings Miss Estimates, Pipeline Progress in Focus

Prothena Corporation PRTA reported third-quarter 2025 adjusted loss per share (excluding restructuring costs) of 67 cents, much wider than the Zacks Consensus Estimate of a loss of 60 cents. In the year-ago quarter, the company reported a loss of $1.10 per share.

Revenues totaled $2.4 million, which missed the Zacks Consensus Estimate of $25 million. Prothena recorded revenues of $0.1 million in the year-ago quarter.

The company’s shares have lost 27.2% year to date against the industry’s gain of 12.1%.

PRTA’s Q3 Results in Detail

Research and development (R&D) expenses plunged 42.9% year over year to $28.9 million, primarily due to lower clinical trial, manufacturing, personnel and consulting expenses.

General and administrative expenses amounted to $13.2 million, down 21% year over year.

As of Sept. 30, 2025, Prothena had $331.7 million in cash, cash equivalents and restricted cash, and no debt.

PRTA’s Pipeline Updates

The company is evaluating prasinezumab, in collaboration with Roche RHHBY, for the treatment of Parkinson’s disease (PD).

Partner Roche will initiate the late-stage PARAISO study evaluating prasinezumab for early-stage Parkinson's disease by the end of 2025.

Roche expects peak sales potential of greater than $3.5 billion (unadjusted) of prasinezumab.

Novo Nordisk NVO had earlier acquired Prothena’s clinical-stage antibody, Coramitug (formerly PRX004), a potential first-in-class amyloid depleter antibody for the treatment of ATTR amyloidosis with cardiomyopathy.

Novo Nordisk initiated the late-stage CLEOPATTRA study evaluating Coramitug for ATTR-CM.

PRTA expects to earn a clinical milestone when prespecified enrollment criteria are met in ongoing phase III study by Novo Nordisk.

Prothena is advancing an early-stage pipeline of programs for several potential neurological indications with Bristol Myers BMY.

BMS-986446 (formerly PRX005) is a best-in-class anti-tau, MTBR-specific antibody for the potential treatment of AD.

BMS-986446 granted Fast Track designation by the FDA as a treatment for Alzheimer’s disease.

Bristol Myers is conducting the phase II TargetTau-1 study in approximately 310 patients with early Alzheimer’s disease and primary completion is expected in 2027. Bristol Myers Squibb is also conducting a phase I open-label single-dose clinical trial to assess a subcutaneous administration, with primary completion expected in the second half of 2025.

PRX019, a potential treatment for neurodegenerative diseases, is also being developed in collaboration with Bristol Myers, which obtained the exclusive global license for the candidate in 2024.

Prothena 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 earn a clinical milestone by the end of 2026, should BMY decide to develop PRX019 further.

PRTA had earlier stated that it plans to explore potential partnership interest to advance PRX012 and its preclinical PRX012-TfR (transferrin receptor) antibody.

Reiterates 2025 Guidance

The company expects 2025 net cash burn from operating and investing activities to be in the range of $170-$178 million. It expects the year-end cash, cash equivalents and restricted cash midpoint to be approximately $298 million. Net loss for 2025 is projected to be in the $240-$248 million range.

PRTA’s Zacks Rank

PRTA carries a Zacks Rank #2 (Buy) at present. You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.

 

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This article originally published on Zacks Investment Research (zacks.com).

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