Plus Therapeutics Completes ReSPECT-LM Phase 1 Trial, Establishes RP2D for Rhenium (186Re) Obisbemeda in Leptomeningeal Metastases

Plus Therapeutics completes ReSPECT-LM Phase 1 trial, establishes RP2D for treating leptomeningeal metastases with Rhenium (186Re) Obisbemeda.

Quiver AI Summary

Plus Therapeutics, Inc. has announced the successful completion of the ReSPECT-LM Phase 1 trial, which evaluated the safety and efficacy of intrathecally administered Rhenium (186Re) Obisbemeda for treating leptomeningeal metastases (LM). The trial determined a recommended phase 2 dose (RP2D) of 44.1 mCi without observed dose-limiting toxicities, with one patient achieving a complete response. Plus Therapeutics plans to advance to a Phase 2 trial and a multi-dose Phase 1 trial, aiming to complete enrollment in both studies in 2025. The company is also in discussions with the FDA regarding the optimal trial pathway. LM is a serious condition causing significant patient mortality, and there are currently no FDA-approved treatments specifically for this complication.

Potential Positives

• Completion of the ReSPECT-LM Phase 1 single-dose escalation trial, establishing the recommended phase 2 dose (RP2D) at 44.1 mCi without any dose-limiting toxicities.
• One patient in Cohort 4 achieved a complete response, indicating a significant positive therapeutic outcome, which is crucial in advancing clinical research.
• Plans to advance into a single dose-expansion Phase 2 trial and a multiple-dose Phase 1 trial, demonstrating ongoing commitment to further research and development in targeted radiotherapeutics.
• Engagement with the U.S. Food & Drug Administration to define the pivotal trial pathway, indicating proactive steps towards potential market approval and commercial viability.

Potential Negatives

• The press release highlights the early stage of the company's product candidates, which may indicate inherent risks and uncertainties in their development and commercialization.
• There is no FDA-approved therapy for leptomeningeal metastases (LM), emphasizing the challenging landscape the company is operating in and the potential for limited market acceptance.
• The mention of significant risks related to liquidity, capital resources, and compliance with Nasdaq listing requirements may raise concerns among investors about the company's financial stability and operational viability.

FAQ

What is the ReSPECT-LM trial by Plus Therapeutics?

The ReSPECT-LM trial is a Phase 1 study evaluating an intrathecal treatment for leptomeningeal metastases using Rhenium (186Re) Obisbemeda.

What was the established RP2D in the trial?

The established RP2D for the trial was 44.1 mCi, determined from Cohort 4, with no dose-limiting toxicities observed.

How many patients experienced a complete response in Cohort 4?

One patient in Cohort 4 achieved a complete response, evidenced by the eradication of tumor cells in the cerebrospinal fluid.

What are the future plans for Plus Therapeutics following the trial?

Plus Therapeutics plans to advance a single dose-expansion Phase 2 trial and a multiple-dose Phase 1 trial to further assess safety and efficacy.

What is the significance of leptomeningeal metastases in cancer patients?

Leptomeningeal metastases are a terminal complication occurring in about 5% of cancer patients, with limited treatment options currently available.

Disclaimer: This is an AI-generated summary of a press release distributed by GlobeNewswire. The model used to summarize this release may make mistakes. See the full release here.

$PSTV Insider Trading Activity

$PSTV insiders have traded $PSTV stock on the open market 6 times in the past 6 months. Of those trades, 6 have been purchases and 0 have been sales.

Here’s a breakdown of recent trading of $PSTV stock by insiders over the last 6 months:

• GREG PETERSEN purchased 12,500 shares for an estimated $16,875
• RICHARD J HAWKINS has made 2 purchases buying 10,285 shares for an estimated $14,507 and 0 sales.
• MARC H HEDRICK (Chief Executive Officer) purchased 8,000 shares for an estimated $9,839
• HOWARD CLOWES purchased 5,000 shares for an estimated $6,681
• ANDREW JOHN HUGH MACINTYRE SIMS (Chief Financial Officer) purchased 4,098 shares for an estimated $5,204

To track insider transactions, check out Quiver Quantitative's insider trading dashboard.

$PSTV Hedge Fund Activity

We have seen 3 institutional investors add shares of $PSTV stock to their portfolio, and 4 decrease their positions in their most recent quarter.

Here are some of the largest recent moves:

• CITADEL ADVISORS LLC removed 18,283 shares (-100.0%) from their portfolio in Q3 2024, for an estimated $26,693
• TWO SIGMA SECURITIES, LLC added 14,587 shares (+inf%) to their portfolio in Q4 2024, for an estimated $16,775
• ASHTON THOMAS PRIVATE WEALTH, LLC removed 12,913 shares (-100.0%) from their portfolio in Q4 2024, for an estimated $14,849
• GEODE CAPITAL MANAGEMENT, LLC added 3,876 shares (+7.1%) to their portfolio in Q4 2024, for an estimated $4,457
• UBS GROUP AG removed 3,199 shares (-100.0%) from their portfolio in Q3 2024, for an estimated $4,670
• TOWER RESEARCH CAPITAL LLC (TRC) added 1,073 shares (+28.9%) to their portfolio in Q4 2024, for an estimated $1,233
• JPMORGAN CHASE & CO removed 100 shares (-100.0%) from their portfolio in Q4 2024, for an estimated $114

To track hedge funds' stock portfolios, check out Quiver Quantitative's institutional holdings dashboard.

Full Release

AUSTIN, Texas, Feb. 26, 2025 (GLOBE NEWSWIRE) -- Plus Therapeutics, Inc. (Nasdaq: PSTV) (the “Company” or “Plus Therapeutics”), a clinical-stage pharmaceutical company developing targeted radiotherapeutics with advanced platform technologies for central nervous system (CNS) cancers, today announced the completion of the ReSPECT-LM Phase 1 single-dose escalation trial, having determined an RP2D.

The ReSPECT-LM single-dose escalation trial assessed the safety, tolerability, and potential efficacy of intrathecally administered Rhenium (

¹⁸⁶

Re) Obisbemeda in patients with leptomeningeal metastases (LM). Enrollment in Cohort 6 was recently completed (75.0 mCi). The Cohort 4 dose (44.1 mCi) was determined to be the RP2D; no dose-limiting toxicities were observed at this dose level. One patient at the Cohort 4 dose was observed to have achieved a complete response, as evidenced by the eradication of tumor cells in the cerebrospinal fluid—a key therapeutic endpoint.

"With the RP2D established, we are advancing both a single dose-expansion Phase 2 trial and a multiple-dose Phase 1 trial of 44.1 mCi fractionated into three doses to further assess safety and efficacy," said Marc H. Hedrick, M.D., Plus Therapeutics President and Chief Executive Officer. "We remain on track to complete enrollment in both trials this year and are simultaneously engaging the U.S. Food & Drug Administration to define the optimal pivotal trial pathway."

Additional details on the ReSPECT-LM trial can be found

here

.

About Leptomeningeal Metastases (LM)

LM is a rare complication of cancer in which the primary cancer spreads to the cerebrospinal fluid (CSF) and leptomeninges surrounding the brain and spinal cord. All malignancies originating from solid tumors, primary brain tumors, or hematological malignancies have this LM complication potential with breast cancer as the most common cancer linked to LM, with 3-5% of breast cancer patients developing LM. Additionally, lung cancer, GI cancers and melanoma can also spread to the CSF and result in LM. LM occurs in approximately 5% of people with cancer and is usually terminal with 1-year and 2-year survival of just 7% and 3%, respectively. The incidence of LM is on the rise, partly because cancer patients are living longer and partly because many standard chemotherapies cannot reach sufficient concentrations in the spinal fluid to kill the tumor cells, yet there are no FDA-approved therapies specifically for LM patients, who often succumb to this complication within weeks to several months, if untreated.

About Plus Therapeutics



Plus Therapeutics, Inc. is a clinical-stage pharmaceutical company developing targeted radiotherapeutics for difficult-to-treat cancers of the central nervous system with the potential to enhance clinical outcomes for patients. Combining image-guided local beta radiation and targeted drug delivery approaches, the Company is advancing a pipeline of product candidates with lead programs in recurrent glioblastoma (GBM) and LM. The Company has built a supply chain through strategic partnerships that enable the development, manufacturing and future potential commercialization of its products. Plus Therapeutics is led by an experienced and dedicated leadership team and has operations in key cancer clinical development hubs, including Austin and San Antonio, Texas. For more information, visit https://plustherapeutics.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, including statements regarding clinical trials, expected operations and upcoming developments. 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 “expect” “potential,” “anticipating,” “planning” 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 under the heading Upcoming Events and Expected Milestones, and statements regarding the following: the potential promise of rhenium (

¹⁸⁶

Re) obisbemeda; expectations as to the Company’s future performance, including the next steps in developing the Company’s product candidates; the Company’s clinical trials, including statements regarding the timing and characteristics of the ReSPECT-LM single dose and multi-dose clinical trials; the continued evaluation of rhenium (

¹⁸⁶

Re) obisbemeda including through evaluations in additional patient cohorts.

The forward-looking statements included in this press release could differ materially from those expressed or implied by these forward-looking statements because of risks, uncertainties, and other factors that include, but are 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, including the ability of the Company to come into compliance with The Nasdaq Capital Market listing requirements; market conditions, product performance, litigation or potential litigation, and competition within the cancer diagnostics and therapeutics field; ability to develop and protect proprietary intellectual property or obtain licenses to intellectual property developed by others on commercially reasonable and competitive terms; challenges associated with radiotherapeutic manufacturing, production and distribution capabilities necessary to support the Company’s clinical trials and any commercial level product demand; and material security breach or cybersecurity attack affecting the Company’s operations or property. This list of risks, uncertainties, and other factors is not complete. Plus Therapeutics discusses some of these matters more fully, as well as certain risk factors that could affect Plus Therapeutics’ business, financial condition, results of operations, and prospects, in its reports filed with the SEC, including Plus Therapeutics’ annual report on Form 10-K for the fiscal year ended December 31, 2023, quarterly reports on Form 10-Q, and current reports on Form 8-K. These filings are available for review through the SEC’s website at www.sec.gov. Any or all forward-looking statements Plus Therapeutics makes may turn out to be wrong and can be affected by inaccurate assumptions Plus Therapeutics might make or by known or unknown risks, uncertainties, and other factors, including those identified in this press release. Accordingly, you should not place undue reliance on the forward-looking statements made in this press release, which speak only as of its date. 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.

Investor Contact



Charles Y. Huang, MBA


Director of Capital Markets and Investor Relations


Office: (202)-209-5751 | Direct (301)-728-7222



chuang@plustherapeutics.com

The views and opinions expressed herein are the views and opinions of the author and do not necessarily reflect those of Nasdaq, Inc.