PRTA's Q2 Loss Narrower Than Expected, Pipeline Progress in Focus

Prothena Corporation PRTA reported second-quarter 2026 adjusted loss per share (excluding restructuring costs) of 32 cents, narrower than the Zacks Consensus Estimate of a loss of 39 cents per share.

In the year-ago quarter, the company had incurred a loss of $1.73 per share.

Revenues totaled $1.01 million compared with $4.4 million in the year-ago quarter. The metric matched the Zacks Consensus Estimate of $1 million. The top line primarily comprises collaboration revenues from Bristol Myers Squibb BMY for the PRX019 phase I study.

Prothena’s shares have declined 10.2% so far this year against the industry’s 4.3% growth.

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PRTA’s Q2 Results in Detail

Research and development (R&D) expenses decreased 78.3% to $8.8 million from $40.5 million in the prior-year period, primarily driven by lower clinical trial, personnel, manufacturing and consulting expenses.

General and administrative (G&A) expenses decreased 31.5% to $10.9 million from $15.9 million in the year-ago period, mainly due to lower consulting and personnel expenses.

As of June 30, 2026, Prothena had $330.3 million in cash, cash equivalents and restricted cash, compared with $330.3 million as of March 31, 2026. The company had no debt at the end of the second quarter.

As of June 30, 2026, the company had repurchased 2,243,888 ordinary shares for approximately $22.3 million, excluding commissions and expenses, under its share repurchase program, which authorizes up to $100 million in buybacks through Dec. 31, 2026.

PRTA Updates 2026 Guidance

Prothena reaffirmed its guidance for full-year 2026 net cash used in operating and investing activities to $18-$23 million. The company expects to end 2026 with approximately $259 million in cash, cash equivalents and restricted cash at the midpoint, down $14 million from the previous midpoint guidance of $273 milliondue to approximately $12 million spent on share repurchases.

The guidance assumes a net loss of $25-$30 million, including $26 million in non-cash share-based compensation expenses.

The company’s financial guidance does not include the receipt of a $55 million clinical milestone payment tied to BMY’s advancement of PRX019 for neurodegenerative diseases, nor does it factor in any additional cash that may be used under the share repurchase program.

PRTA’s Pipeline Updates

Prothena continued to advance its partnered pipeline during the quarter. It is developing prasinezumab in collaboration with Roche RHHBY for the treatment of Parkinson’s disease.

Roche is evaluating prasinezumab in an ongoing late-stage PARAISO study for early-stage Parkinson's disease, with primary completion expected in 2029. Roche expects prasinezumab to have peak sales potential of more than $3.5 billion (unadjusted).

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

NVO is evaluating the candidate under a late-stage CLEOPATTRA study for ATTR-CM. The study is expected to be completed by 2029.

The open-label study evaluating the biodistribution of 89Zr-coramitug and assessing coramitug’s ability to reduce TTR amyloid deposits in myocardial tissue using PET/CT imaging in patients with ATTR-CM is ongoing, with primary completion expected in 2027 (NCT07448623).

Last quarter, Prothena received a $50 million clinical milestone payment tied to the enrollment progress in the ongoing study of coramitug. It is advancing an early-stage pipeline of programs for several potential neurological indications with Bristol Myers.

Moponetug (formerly BMS-986446/PRX005) is a best-in-class anti-tau, MTBR-specific antibody for the potential treatment of Alzheimer’s Disease.

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

PRX019, a potential treatment for neurodegenerative diseases, is being developed in collaboration with Bristol Myers. BMY in-licensed exclusive global rights to PRX019 in 2024.

Prothena completed a phase I study evaluating the safety, tolerability, immunogenicity and pharmacokinetics of single-ascending and multiple-dose administration in healthy volunteers.

The company could receive a potential $55 million clinical milestone payment if BMY elects to advance the program, with a decision expected by year-end 2026.

Prothena Corporation plc Price, Consensus and EPS Surprise

Prothena Corporation plc price-consensus-eps-surprise-chart | Prothena Corporation plc Quote

PRTA’s Zacks Rank

PRTA carries a Zacks Rank #3 (Hold) at present. You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.

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