ETON · Eton Pharmaceuticals, Inc.

On July 31, 2026, the reporting person was granted 128,985 performance-vested restricted stock units granted under the Issuer's 2018 equity incentive plan. Each restricted stock unit represents the right to acquire one share of Issuer common stock. The award vests in full, and all restrictions lapse, immediately upon the closing price of the Issuer's common stock equaling or exceeding $72.36 per share for one trading day at any time prior to the third anniversary of the grant date. If this market condition is not satisfied prior to such date, the award will be forfeited in its entirety without consideration on July 31, 2029.The number of shares reported reflects the maximum and only number of shares issuable under the award; there is no target, threshold, or maximum range.

On July 31, 2026, the reporting person was granted 128,985 performance-vested restricted stock units granted under the Issuer's 2018 equity incentive plan. Each restricted stock unit represents the right to acquire one share of Issuer common stock. The award vests in full, and all restrictions lapse, immediately upon the closing price of the Issuer's common stock equaling or exceeding $72.36 per share for one trading day at any time prior to the third anniversary of the grant date. If this market condition is not satisfied prior to such date, the award will be forfeited in its entirety without consideration on July 31, 2029.The number of shares reported reflects the maximum and only number of shares issuable under the award; there is no target, threshold, or maximum range.

On July 31, 2026, the reporting person was granted 80,000 performance-vested restricted stock units granted under the Issuer's 2018 equity incentive plan. Each restricted stock unit represents the right to acquire one share of Issuer common stock. The award vests in full, and all restrictions lapse, immediately upon the closing price of the Issuer's common stock equaling or exceeding $72.36 per share for one trading day at any time prior to the third anniversary of the grant date. If this market condition is not satisfied prior to such date, the award will be forfeited in its entirety without consideration on July 31, 2029.The number of shares reported reflects the maximum and only number of shares issuable under the award; there is no target, threshold, or maximum range.

On July 31, 2026, the reporting person was granted 10,000 performance-vested restricted stock units granted under the Issuer's 2018 equity incentive plan. Each restricted stock unit represents the right to acquire one share of Issuer common stock. The award vests in full, and all restrictions lapse, immediately upon the closing price of the Issuer's common stock equaling or exceeding $72.36 per share for one trading day at any time prior to the third anniversary of the grant date. If this market condition is not satisfied prior to such date, the award will be forfeited in its entirety without consideration on July 31, 2029.The number of shares reported reflects the maximum and only number of shares issuable under the award; there is no target, threshold, or maximum range.

On July 31, 2026, the reporting person was granted 10,000 performance-vested restricted stock units granted under the Issuer's 2018 equity incentive plan. Each restricted stock unit represents the right to acquire one share of Issuer common stock. The award vests in full, and all restrictions lapse, immediately upon the closing price of the Issuer's common stock equaling or exceeding $72.36 per share for one trading day at any time prior to the third anniversary of the grant date. If this market condition is not satisfied prior to such date, the award will be forfeited in its entirety without consideration on July 31, 2029.The number of shares reported reflects the maximum and only number of shares issuable under the award; there is no target, threshold, or maximum range.

On July 31, 2026, the reporting person was granted 32,246 performance-vested restricted stock units granted under the Issuer's 2018 equity incentive plan. Each restricted stock unit represents the right to acquire one share of Issuer common stock. The award vests in full, and all restrictions lapse, immediately upon the closing price of the Issuer's common stock equaling or exceeding $72.36 per share for one trading day at any time prior to the third anniversary of the grant date. If this market condition is not satisfied prior to such date, the award will be forfeited in its entirety without consideration on July 31, 2029.The number of shares reported reflects the maximum and only number of shares issuable under the award; there is no target, threshold, or maximum range.

On July 31, 2026, the reporting person was granted 10,000 performance-vested restricted stock units granted under the Issuer's 2018 equity incentive plan. Each restricted stock unit represents the right to acquire one share of Issuer common stock. The award vests in full, and all restrictions lapse, immediately upon the closing price of the Issuer's common stock equaling or exceeding $72.36 per share for one trading day at any time prior to the third anniversary of the grant date. If this market condition is not satisfied prior to such date, the award will be forfeited in its entirety without consideration on July 31, 2029.The number of shares reported reflects the maximum and only number of shares issuable under the award; there is no target, threshold, or maximum range.

On July 31, 2026, the reporting person was granted 10,000 performance-vested restricted stock units granted under the Issuer's 2018 equity incentive plan. Each restricted stock unit represents the right to acquire one share of Issuer common stock. The award vests in full, and all restrictions lapse, immediately upon the closing price of the Issuer's common stock equaling or exceeding $72.36 per share for one trading day at any time prior to the third anniversary of the grant date. If this market condition is not satisfied prior to such date, the award will be forfeited in its entirety without consideration on July 31, 2029.The number of shares reported reflects the maximum and only number of shares issuable under the award; there is no target, threshold, or maximum range.

The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $37.0152 to $37.9148 inclusive. The reporting person undertakes to provide, upon request by the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each price.

Securities owned by a separately managed account (the "Managed Account"). As the portfolio manager of the Managed Account, Opaleye Management, Inc. may be deemed to beneficially own the securities owned directly by the Managed Account.

Opaleye Management, Inc. disclaims beneficial ownership of the shares reported herein except to the extent of its pecuniary interest therein, and the filing of this Form 4 shall not be construed as an admission that Opaleye Management, Inc. is the beneficial owner of any such shares for purposes of Section 16(a) of the Securities Exchange Act of 1934, as amended, or for any other purpose.

The shares subject to the option vested annually from the date of grant (11-10-2017) in four equal installments.

The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $37.0152 to $37.9148 inclusive. The reporting person undertakes to provide, upon request by the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each price.

Represents securities owned directly by Opaleye, L.P. (the "Fund"). As the investment manager of the Fund, Opaleye Management, Inc. may be deemed to beneficially own the securities owned directly by the Fund.

Opaleye Management, Inc. disclaims beneficial ownership of the shares reported herein except to the extent of its pecuniary interest therein, and the filing of this Form 4 shall not be construed as an admission that Opaleye Management, Inc. is the beneficial owner of any such shares for purposes of Section 16(a) of the Securities Exchange Act of 1934, as amended, or for any other purpose.

On July 12, 2022, the reporting person was granted 40,000 restricted stock units which vested in four equal annual installments beginning July 12, 2023.

On July 12, 2022, the reporting person was granted 40,000 restricted stock units which vested in four equal annual installments beginning July 12, 2023.

On July 12, 2022, the reporting person was granted 110,000 restricted stock units which vested in four equal installments beginning July 12, 2023.

On July 12, 2022, the reporting person was granted 110,000 restricted stock units which vested in four equal installments beginning July 12, 2023.

The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $38.00 to $38.565 inclusive. The reporting person undertakes to provide, upon request by the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each price.

Securities owned by a separately managed account (the "Managed Account"). As the portfolio manager of the Managed Account, Opaleye Management, Inc. may be deemed to beneficially own the securities owned directly by the Managed Account.

Opaleye Management, Inc. disclaims beneficial ownership of the shares reported herein except to the extent of its pecuniary interest therein, and the filing of this Form 4 shall not be construed as an admission that Opaleye Management, Inc. is the beneficial owner of any such shares for purposes of Section 16(a) of the Securities Exchange Act of 1934, as amended, or for any other purpose.

The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $38.00 to $38.565 inclusive. The reporting person undertakes to provide, upon request by the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each price.

Represents securities owned directly by Opaleye, L.P. (the "Fund"). As the investment manager of the Fund, Opaleye Management, Inc. may be deemed to beneficially own the securities owned directly by the Fund.

Opaleye Management, Inc. disclaims beneficial ownership of the shares reported herein except to the extent of its pecuniary interest therein, and the filing of this Form 4 shall not be construed as an admission that Opaleye Management, Inc. is the beneficial owner of any such shares for purposes of Section 16(a) of the Securities Exchange Act of 1934, as amended, or for any other purpose.

Represents securities owned directly by Opaleye, L.P. (the "Fund"). As the investment manager of the Fund, Opaleye Management, Inc. may be deemed to beneficially own the securities owned directly by the Fund.

Opaleye Management, Inc. disclaims beneficial ownership of the shares reported herein except to the extent of its pecuniary interest therein, and the filing of this Form 4 shall not be construed as an admission that Opaleye Management, Inc. is the beneficial owner of any such shares for purposes of Section 16(a) of the Securities Exchange Act of 1934, as amended, or for any other purpose.

The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $37.05 to $37.85 inclusive. The reporting person undertakes to provide, upon request by the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each price.

Securities owned by a separately managed account (the "Managed Account"). As the portfolio manager of the Managed Account, Opaleye Management, Inc. may be deemed to beneficially own the securities owned directly by the Managed Account.

Opaleye Management, Inc. disclaims beneficial ownership of the shares reported herein except to the extent of its pecuniary interest therein, and the filing of this Form 4 shall not be construed as an admission that Opaleye Management, Inc. is the beneficial owner of any such shares for purposes of Section 16(a) of the Securities Exchange Act of 1934, as amended, or for any other purpose.

The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $37.05 to $37.85 inclusive. The reporting person undertakes to provide, upon request by the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each price.

Represents securities owned directly by Opaleye, L.P. (the "Fund"). As the investment manager of the Fund, Opaleye Management, Inc. may be deemed to beneficially own the securities owned directly by the Fund.

Opaleye Management, Inc. disclaims beneficial ownership of the shares reported herein except to the extent of its pecuniary interest therein, and the filing of this Form 4 shall not be construed as an admission that Opaleye Management, Inc. is the beneficial owner of any such shares for purposes of Section 16(a) of the Securities Exchange Act of 1934, as amended, or for any other purpose.

Each restricted stock unit represents a contingent right to receive one share of ETON Common Stock.

The restricted stock units vest in four equal annual installments beginning June 26, 2027, contingent upon the reporting person being employed by the issuer on the date(s) of vesting.

The shares subject to the option vested on a quarterly basis over 12 months from the date of grant until fully vested on February 7, 2023.

The Reporting Person will provide upon request by the Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.

The shares were sold in multiple trades at prices ranging from $32.10 to $32.71. The price reported above reflects the weighted average sales price.

The shares were sold in multiple trades at prices ranging from $31.59 to $32.55. The price above reflects the weighted average sales price.

The Reporting Person will provide upon request by the Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.

The shares subject to the option vested in 48 equal monthly installments from the date of grant (3-12-2020) until fully vested.

The shares subject to the option vested annually from the date of grant (11-10-2017) in four equal installments.

The Reporting Person will provide upon request by the Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.

The shares were sold in multiple trades at prices ranging from $31.25 to $31.825. The price reported above reflects the weighted average sales price.

The shares subject to option vested annually from the date of grant (8-7-2017) in four equal installments.

The Reporting Person will provide upon request by the Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.

The shares were sold in multiple trades at prices ranging from $31.27 to $32.16. The price reported above reflects the weighted average sales price.

The shares subject to the option vested annually from the date of grant (11-10-2017) in four equal installments.

The Reporting Person will provide upon request by the Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.

The shares were sold in multiple trades at prices ranging from $32.67 to $33.65. The price reported above reflects the weighted average sales price.

The Reporting Person will provide upon request by the Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.

The shares were sold in multiple trades at prices ranging from $33.68 to $34.66. The price reported above reflects the weighted average sales price.

The shares subject to the option vested in 48 equal monthly installments from the date of grant (3-12-2020) until fully vested.

Shares withheld by the Issuer to satisfy applicable withholding taxes upon the vesting of restricted stock units.

The Reporting Person will provide upon request by the Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares purchased or sold at each separate price.

Shares withheld by the Issuer to satisfy applicable withholding taxes upon the vesting of restricted stock units.

The shares were sold in multiple trades at prices ranging from $15.46 to $15.48. The price reported above reflects the weighted average sales price.

The Reporting Person will provide upon request by the Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares purchased or sold at each separate price.