Subsequent Events	9 Months Ended
Sep. 30, 2024
Subsequent Events [Abstract]
Subsequent Events	11. Subsequent Events GSK License Agreement On October 21, 2024, the Company entered into Amendment 4 to the GSK License Agreement, under which the Company may receive an additional $0.8 million upon completion of activities related to an additional clinical study. Strategic Restructuring and Reduction in Workforce On October 29, 2024, the Company announced that it would suspend its current development activities for SPR720 based on an interim analysis of the Phase 2a proof-of-concept study of SPR720 for the treatment of NTM-PD not meeting its primary endpoint. While the data showed antimicrobial activity associated with SPR720, the interim analysis did not show sufficient separation from placebo and highlighted potential dose limiting safety issues in subjects dosed at 1,000 mg orally once daily, including three cases of reversible grade 3 hepatotoxicity. In evaluating the totality of both the efficacy and safety data, the Company elected to suspend its current development program for SPR720 and will evaluate other potential paths forward as the remaining data are collected and analyzed. As a result, the Company has restructured its operations to focus on supporting the development of tebipenem HBr and other potential corporate activities while it continues to seek a pathway forward for SPR720. In connection with the foregoing, the Company implemented a strategic restructuring initiative and corresponding workforce reduction. The restructuring initiative and corresponding reduction in workforce is designed to reduce costs and reallocate resources towards the Company’s support of the development of tebipenem HBr, while maintaining key personnel needed to help preserve the value of the Company’s programs. The restructuring reduced the Company’s workforce by approximately 39%. The Company estimates that it will incur approximately $1.1 million in costs in connection with the workforce reduction related to severance pay and other termination benefits. Further, in connection with the restructuring, on October 29, 2024, the Board of Directors approved retention awards for non-executive employees of the Company. Subject to remaining actively employed and in good standing with the Company, aggregate retention awards of $4.4 million will be paid as a cash bonus with one half payable upon the achievement of each of two clinical execution milestones related to facilitating the clinical progress of PIVOT-PO. The estimated charges that the Company expects to incur as a result of the restructuring are subject to several assumptions, and actual results may differ materially from these estimates. The Company may incur additional costs not currently contemplated due to events associated with or resulting from the workforce reduction. The Company communicated the workforce reduction on October 29, 2024, and expects most of the costs associated with the workforce reduction to be incurred during the quarter ending December 31, 2024. On November 8, 2024, the Compensation Committee of the Board of Directors approved a retention program for the Company’s executive leadership team (ELT), which consists of four executive officers, including our Chief Executive Officer, Chief Financial and Chief Business Officer, Chief Operating Officer and Chief Human Resources Officer. The purpose of the program is to ensure that the Company retains ELT members who are considered critical to the development of tebipenem HBr in its ongoing PIVOT-PO, global Phase 3 clinical trial of tebipenem HBr in patients with cUTI. The retention program provides these ELT members with the opportunity to earn a cash bonus in an amount equaling 75% of the aggregate of their current base salary plus target annual bonus upon achievement of certain performance milestones relating to facilitating the progress of PIVOT-PO and certain goals related to the Company’s stock price appreciation or financial stewardship. Specifically, one-third of the retention payout is payable upon the achievement of each of two clinical execution milestones. The remaining one-third is payable upon the achievement of the stock price appreciation or financial stewardship milestone by no later than late 2026. If fully achieved, the total retention payments would aggregate to $2.1 million. The program contains certain clawback provisions in the event an executive voluntarily terminates his or her employment prior to the achievement of the second clinical execution milestone. The program also provides for full payment in the event of certain change in control transactions. Prior to the end of the performance period, if the Company terminates an executive’s employment, other than for cause, then such executive will be entitled to payment of the clinical execution milestone payments. In the event that the Company’s collaboration partner materially alters the PIVOT-PO work plan with the effect of preventing or indefinitely delaying the achievement of the clinical execution milestones, then the clinical execution milestone payments will be accelerated and paid in full.

Subsequent Events

9 Months Ended

Sep. 30, 2024

11. Subsequent Events

GSK License Agreement

On October 21, 2024, the Company entered into Amendment 4 to the GSK License Agreement, under which the Company may receive an additional $0.8 million upon completion of activities related to an additional clinical study.

Strategic Restructuring and Reduction in Workforce

On October 29, 2024, the Company announced that it would suspend its current development activities for SPR720 based on an interim analysis of the Phase 2a proof-of-concept study of SPR720 for the treatment of NTM-PD not meeting its primary endpoint. While the data showed antimicrobial activity associated with SPR720, the interim analysis did not show sufficient separation from placebo and highlighted potential dose limiting safety issues in subjects dosed at 1,000 mg orally once daily, including three cases of reversible grade 3 hepatotoxicity. In evaluating the totality of both the efficacy and safety data, the Company elected to suspend its current development program for SPR720 and will evaluate other potential paths forward as the remaining data are collected and analyzed. As a result, the Company has restructured its operations to focus on supporting the development of tebipenem HBr and other potential corporate activities while it continues to seek a pathway forward for SPR720. In connection with the foregoing, the Company implemented a strategic restructuring initiative and corresponding workforce reduction. The restructuring initiative and corresponding reduction in workforce is designed to reduce costs and reallocate resources towards the Company’s support of the development of tebipenem HBr, while maintaining key personnel needed to help preserve the value of the Company’s programs. The restructuring reduced the Company’s workforce by approximately 39%. The Company estimates that it will incur approximately $1.1 million in costs in connection with the workforce reduction related to severance pay and other termination benefits.

Further, in connection with the restructuring, on October 29, 2024, the Board of Directors approved retention awards for non-executive employees of the Company. Subject to remaining actively employed and in good standing with the Company, aggregate retention awards of $4.4 million will be paid as a cash bonus with one half payable upon the achievement of each of two clinical execution milestones related to facilitating the clinical progress of PIVOT-PO. The estimated charges that the Company expects to incur as a result of the restructuring are subject to several assumptions, and actual results may differ materially from these estimates. The Company may incur additional costs not currently contemplated due to events associated with or resulting from the workforce reduction. The Company communicated the workforce reduction on October 29, 2024, and expects most of the costs associated with the workforce reduction to be incurred during the quarter ending December 31, 2024.

On November 8, 2024, the Compensation Committee of the Board of Directors approved a retention program for the Company’s executive leadership team (ELT), which consists of four executive officers, including our Chief Executive Officer, Chief Financial and Chief Business Officer, Chief Operating Officer and Chief Human Resources Officer. The purpose of the program is to ensure that the Company retains ELT members who are considered critical to the development of tebipenem HBr in its ongoing PIVOT-PO, global Phase 3 clinical trial of tebipenem HBr in patients with cUTI. The retention program provides these ELT members with the opportunity to earn a cash bonus in an amount equaling 75% of the aggregate of their current base salary plus target annual bonus upon achievement of certain performance milestones relating to facilitating the progress of PIVOT-PO and certain goals related to the Company’s stock price appreciation or financial stewardship. Specifically, one-third of the retention payout is payable upon the achievement of each of two clinical execution milestones. The remaining one-third is payable upon the achievement of the stock price appreciation or financial stewardship milestone by no later than late 2026. If fully achieved, the total retention payments would aggregate to $2.1 million. The program contains certain clawback provisions in the event an executive voluntarily terminates his or her employment prior to the achievement of the second clinical execution milestone. The program also provides for full payment in the event of certain change in control transactions. Prior to the end of the performance period, if the Company terminates an

executive’s employment, other than for cause, then such executive will be entitled to payment of the clinical execution milestone payments. In the event that the Company’s collaboration partner materially alters the PIVOT-PO work plan with the effect of preventing or indefinitely delaying the achievement of the clinical execution milestones, then the clinical execution milestone payments will be accelerated and paid in full.