PROTHENA CORP PUBLIC LTD CO reported that Chief Accounting Officer Karin L. Walker acquired a stock option covering 150,000 shares of the company’s stock. This option was reported as a grant or award acquisition in a Form 4 insider filing.
According to the vesting terms, 25% of the 150,000 shares subject to the option will vest and become exercisable on March 3, 2027. The remaining portion will vest in 1/48th increments in equal monthly installments on each monthly anniversary after that date, conditioned on Ms. Walker’s continued employment with the company on each vesting date.
PROTHENA CORP PUBLIC LTD CO reported that Chief Development Officer Chad J. Swanson acquired a grant of 190,000 stock options on March 3, 2026. The options were awarded at no cost as a “Stock Option (Right to Buy).”
According to the vesting terms, 25% of the total options will vest and become exercisable on March 3, 2027. The remaining options will vest in equal monthly installments of 1/48th of the total number of shares on each monthly anniversary thereafter, subject to his continued employment with the company on each vesting date.
PROTHENA CORP PUBLIC LTD CO granted Chief Operating Officer Brandon S. Smith a stock option covering 190,000 shares on March 3, 2026. This option was reported as a direct, derivative security and classified as a grant or award acquisition.
According to the vesting terms, 25% of the shares underlying the option will vest and become exercisable on March 3, 2027. The remaining shares will vest in 1/48th monthly installments on each monthly anniversary thereafter, conditioned on Smith’s continued employment with the company on each vesting date.
Nguyen Tran reported acquisition or exercise transactions in this Form 4 filing.
PROTHENA CORP PUBLIC LTD CO granted Nguyen Tran, its Chief Strategy Officer and CFO, a stock option covering 230,000 shares. The option vests as to 25% of the shares on March 3, 2027, with the remaining 75% vesting in equal monthly installments over the following three years, subject to continued employment.
Malecek Michael J reported acquisition or exercise transactions in this Form 4 filing.
Prothena Corp Public Ltd Co granted Chief Legal Officer Michael J. Malecek a stock option covering 190,000 shares of the company’s stock. According to the award terms, 25% of the option will vest and become exercisable on March 3, 2027. The remaining shares will vest in equal monthly installments of 1/48th of the total option on each monthly anniversary thereafter, subject to his continued employment with the company on each vesting date.
Kinney Gene G. reported acquisition or exercise transactions in this Form 4 filing.
PROTHENA CORP PUBLIC LTD CO reported that President and CEO Gene G. Kinney received a grant of stock options covering 520,000 shares on March 3, 2026. These options vest as to 25% of the total shares on March 3, 2027, then in equal monthly installments of 1/48th of the total shares on each monthly anniversary thereafter, subject to his continued employment with the company.
Prothena Corporation plc announced that its board has authorized a share repurchase plan allowing the company to buy back up to $100.0 million of its outstanding ordinary shares. The plan runs through December 31, 2026, is fully discretionary, and can be suspended or ended at any time.
Prothena reported $308.4 million in cash, cash equivalents and restricted cash and no debt as of December 31, 2025, and expects to end 2026 with about $255 million in cash excluding any repurchases. The company also highlights potential to earn up to $105 million in 2026 clinical milestone payments from strategic partners Novo Nordisk and Bristol Myers Squibb.
Prothena Corporation plc amends its S-3 shelf to register up to $200,000,000 of ordinary shares for issuance from time to time after the registration statement is effective. This post-effective amendment also states the company is no longer a well-known seasoned issuer.
Each future issuance will be described in a prospectus supplement that sets amounts, prices and terms. The filing discloses issued ordinary shares of 53,832,982 as of December 31, 2025 as a context figure.
Prothena Corporation plc filed its annual report describing a late-stage biotechnology company focused on diseases caused by protein misfolding, particularly neurodegenerative and rare amyloid disorders. Its pipeline spans wholly owned and partnered antibody, small‑molecule and vaccine programs.
Key partnered assets include prasinezumab with Roche for Parkinson’s disease, coramitug with Novo Nordisk for ATTR cardiomyopathy, and BMS-986446 and PRX019 with Bristol Myers Squibb for Alzheimer’s and other neurodegenerative diseases. Early programs feature the CYTOPE® intracellular targeting platform, Alzheimer’s candidates PRX012 and PRX012‑TfR, and dual Aβ‑tau vaccine PRX123.
The company discontinued development of birtamimab after the Phase 3 AFFIRM‑AL trial failed to meet its endpoints and implemented an approximate 63% workforce reduction in 2025 to lower operating costs while continuing to support key collaborations and selected wholly owned projects.
Prothena Corporation plc amends its shelf registration to permit the offer and issuance of up to $200,000,000 of ordinary shares from time to time. This Post-Effective Amendment notes the company will no longer qualify as a well-known seasoned issuer after filing its Annual Report for the year ended December 31, 2025.
The prospectus describes the general terms for future takedowns under the shelf, the requirement that each offering be accompanied by a prospectus supplement with specific amounts, prices and terms, and that offerings may be conducted through underwriters, dealers, agents or directly to purchasers.