Plus Therapeutics Successfully Completes Key Milestone for cGMP Manufacture of Lead Investigational Radiotherapeutic

Completes technology transfer and initiates cGMP manufacturing for critical Rhenium-186 NanoLiposome (¹⁸⁶RNL) drug product intermediate

On track to manufacture cGMP materials to support ongoing and planned clinical trials for rare cancers in 2022 and beyond

AUSTIN, Texas, July 12, 2022 (GLOBE NEWSWIRE) — Plus Therapeutics, Inc. (Nasdaq: PSTV) (the “Company”), a clinical-stage pharmaceutical company developing innovative, targeted radiotherapeutics for rare and difficult-to-treat cancers, today announced it has reached a key milestone on the path to commercialization of Rhenium-186 NanoLiposome (¹⁸⁶RNL) as the Company completed the technology transfer and initiation of cGMP manufacturing of the ¹⁸⁶RNL drug intermediate with Piramal Pharma Solutions (PPS). Additionally, the intermediate drug product is in stability testing and compliant with U.S. Food and Drug Administration (FDA) guidance for manufacture of liposomal products for use in late-stage clinical trials and commercialization.

In early 2021, Plus Therapeutics entered into a master services agreement with PPS for the development, manufacture and supply of the Company’s ¹⁸⁶RNL drug intermediate product and has now completed the associated technology transfer of analytical test methods and development activities with PPS.

“The Company has met another significant CMC milestone by having fully compliant ¹⁸⁶RNL intermediate, and is on time and on budget to have GMP drug availability in the second half of 2022 for ongoing and planned clinical trials in adults with recurrent glioblastoma, leptomeningeal metastases and future disease targets,” said Marc H. Hedrick M.D., President and Chief Executive Officer of Plus Therapeutics. “Furthermore, in the third quarter of 2022, we plan to issue specific guidance on feedback obtained from two FDA meetings, one based on potential acceptability of Plus Therapeutics’ CMC package and one for feedback on our future plans for clinical development of ¹⁸⁶RNL for recurrent glioblastoma.”

About Plus Therapeutics

Plus Therapeutics, Inc. is a clinical-stage pharmaceutical company focused on the development, manufacture, and commercialization of complex and innovative treatments for patients battling cancer and other life-threatening diseases.

Our proprietary nanotechnology platform is currently centered around the enhanced delivery of a variety of drugs using novel liposomal encapsulation technology. Liposomal encapsulation has been extensively explored and undergone significant technical and commercial advances since it was first developed. Our platform is designed to facilitate new delivery approaches and/or formulations of safe and effective, injectable drugs, potentially enhancing the safety, efficacy and convenience for patients and healthcare providers. More information may be found at PlusTherapeutics.com and ReSPECT-Trials.com.

Cautionary Statement Regarding Forward-Looking Statements

This press release contains statements that may be deemed “forward-looking statements” within the meaning of U.S. securities laws. All statements in this press release other than statements of historical fact are forward-looking statements. These forward-looking statements may be identified by future verbs, as well as terms such as “designed to,” “will,” “can,” “potential,” “focus,” “preparing,” “next steps,” “possibly,” and similar expressions or the negatives thereof. Such statements are based upon certain assumptions and assessments made by management in light of their experience and their perception of historical trends, current conditions, expected future developments and other factors they believe to be appropriate. These statements include, without limitation, statements regarding the following: the potential promise of ¹⁸⁶RNL including the ability of ¹⁸⁶RNL to safely and effectively deliver radiation directly to the tumor at high doses; expectations as to the Company’s future performance including the next steps in developing the Company’s current assets; the Company’s clinical trials including statements regarding the timing and characteristics of the ReSPECT-GBM or the ReSPECT-LM trials; possible negative effects of ¹⁸⁶RNL; the continued evaluation of ¹⁸⁶RNL including through evaluations via a seventh patient cohort; and the intended functions of the Company’s platform and expected benefits from such functions.

The forward-looking statements included in this press release are subject to a number of risks and uncertainties that may cause actual results to differ materially from those discussed in such forward-looking statements. These risks and uncertainties include, but are not limited to: the Company’s actual results may differ, including materially, from those anticipated in these forward-looking statements as a result of various factors, including, but not limited to, the following: the early stage of the Company’s product candidates and therapies, the results of the Company’s research and development activities, including uncertainties relating to the clinical trials of its product candidates and therapies; the Company’s liquidity and capital resources and its ability to raise additional cash, the outcome of the Company’s partnering/licensing efforts, risks associated with laws or regulatory requirements applicable to it, market conditions, product performance, litigation or potential litigation, and competition within the regenerative medicine field, among others; and additional risks described under the heading “Risk Factors” in the Company’s Securities and Exchange Commission filings, including in the Company’s annual and quarterly reports. There may be events in the future that the Company is unable to predict, or over which it has no control, and its business, financial condition, results of operations and prospects may change in the future. The Company assumes no responsibility to update or revise any forward-looking statements to reflect events, trends or circumstances after the date they are made unless the Company has an obligation under U.S. federal securities laws to do so.

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