Plus Therapeutics, Inc. (NASDAQ:PSTV) Q3 2023 Earnings Call Transcript

Plus Therapeutics, Inc. (NASDAQ:PSTV) Q3 2023 Earnings Call Transcript October 31, 2023

Operator: Good afternoon, ladies and gentlemen. Welcome to the Plus Therapeutics Third Quarter 2023 Results Conference Call. Before we begin, we want to advise you that over the course of the call and question-and-answer session, forward-looking statements will be made regarding events, trends, business prospects and financial performance, which may affect Plus Therapeutics' future operating results and financial position. All such statements are subject to risks and uncertainties, including the risks and uncertainties described under the Risk Factors section included in Plus Therapeutics' annual report on Form 10-K and quarterly reports on Form 10-Q filed with the Securities and Exchange Commission from time to time. Plus Therapeutics advises you to review these risk factors and considering such statements Plus Therapeutics assumes no responsibility to update or revise any forward-looking statements to reflect events, trends or circumstances after the date they are made.

It is now my pleasure to turn the floor over to Dr. Marc Hedrick, Plus Therapeutics' President and Chief Executive Officer. Sir, you may begin.

A medical scientist holding up a test tube, illustrating biopharmaceutical research.

Marc Hedrick: Thank you, Tawanda. Good afternoon, everyone. Thank you once again for taking time to join us today as we provide an overview of recent business highlights and discuss our 2023 third quarter financial results. Joining me for the call today are Mr. Andrew Sims, our Chief Financial Officer; and Dr. Norman LaFrance, our Chief Medical Officer. I'll begin the call by reviewing our recent clinical and regulatory progress with a focus on the third quarter and then turn the call over to Andrew to review our financials. Dr. LaFrance will then be joining us for Q&A. I'll begin with updates on our two lead radiotherapeutic CNS cancer programs, starting with recurrent glioblastoma rGBM. Our ReSPECT-GBM trial of Rhenium-186 Obisbemeda in patients with GBM funded substantially by the [Technical Difficulty] it is to enroll as we work to add new sites in order to complete enrollment of the Phase II by the end of 2024.

In parallel to the active Phase II trial, the Phase I dose escalation trial continues to enroll. Assessing the effects of very high administered radiation doses in large volumes to bigger size tumors on radiation distribution, tumor coverage and safety. We presented an update on the ReSPECT-GBM trial at the Society for Neuro-Oncology ASCO meeting in August. To summarize the safety data, a single administration of Rhenium-186 Obisbemeda is generally well tolerated with no dose-limiting toxicities and minimal systemic radiation exposure across 34 GBM patients. In addition, no patients experienced treatment-related adverse events with the outcome of death and no patients withdrew due to AEs. Most AEs were mild or moderate in intensity and nonserious.

The maximum tolerated dose was not reached. With regard to efficacy, as we briefly discussed last quarter, we found that overall survival is highly correlated with absorbed dose and treated tumor volume. In the data set presented at SNO/ASCO, the median absorbed radiation dose to the tumor was 308 gray. When we look at the median overall survival in the Phase I trial through Cohort 6, for patients with absorbed doses less than 100 grey, median overall survival was 22 weeks or about five months. And in contrast for patients with absorbed doses greater than 100 gray, median overall survival was 70 weeks or almost 18 months. Applying the Cox proportional hazard statistical model, we have found that for each 100 gray increase in total absorbed dose, the risk of death decreased by 45.6% and for each 10% increase in the ratio of treated to total tumor volume, the risk of death decreased by 66.9%.

This data can be found in much greater detail on our website. In addition, we continue to assess data from the ongoing Phase II trial. New safety and efficacy data from the Phase II will be presented at SNO in November. Following the SNO meeting, we will be hosting a key opinion leader webinar of investigators to discuss the data in detail. This webinar will feature Neuro-Oncology expert, Dr. Andrew Brenner, who is a principal investigator on the trial and is presenting the data at SNO as well as others. We'll be sharing the details of this event soon and invite you to join us as we delve into the data with these experts more deeply. Now let me update you on our ReSPECT-LM Phase I/IIa dose escalation trial of Rhenium Obisbemeda for patients with leptomeningeal metastases or LM.

This is a trial that is substantially funded by the State of Texas through CPRIT. Following a successful FDA Type C meeting in Q3, we rapidly completed Cohort 4 in the LM trial. Cohort 4 is the first of four planned cohorts in Part B of the Phase I trial. Completing the dosing in Cohort 4 was the fastest enrollment of all the cohorts to-date and enthusiasm from sites to participate enroll patients remains high. Prior to our FDA meeting, we completed Part A of the Phase I trial, specifically cohorts one through three. This past August, we presented the results of these cohorts at the SNO/ASCO meeting and provided further explanation and context at the KOL roundtable event following the August meeting. In summary, for the first three cohorts, the data shows a favorable safety profile and no dose-limiting toxicities have been reached.

Pharmacokinetic analysis showed that the drug circulated rapidly throughout the CSF space and remained there for at least seven days following single administration. Using the CNSide tumor cell enumeration assay, we found that an average reduction of tumor cell counts at 28 days post-treatment of 53%. And finally, median overall survival was 10 months with five of 10 patients still alive. We also presented LM data at the CPRIT innovations in cancer [Technical Difficulty] in September. As mentioned, the ReSPECT-LM Phase I program continues to be funded in part by CPRIT through a three-year $17.6 million product development research funding award. In September, we received a planned $1.9 million advanced payment as part of the grant contract.

Andrew will discuss the forecasted grant revenue going forward for the next couple of years in a moment. Now I'll provide some further color on the CNSide assay used in our LM trial and the license agreement we negotiated for the assay in August. Taking a look at the big picture first. The diagnosis of LM and the monitoring of treatment response are notoriously difficult in LM even with our state-of-the-art imaging clinical evaluation and traditional cerebrospinal fluid evaluation. In contrast, the CNSide assay is highly specific and sensitive as a measure of CSF tumor cell enumeration that quantitates a number of tumor cells per mL of CSF. This technology represents a substantial improvement in assessing CSF tumor cells compared to the standard of care.

At Plus, although we are initially pretty skeptical of the value of the technology and use it as a potential secondary endpoint, our team has seen the value of the assay first-hand in our LM trial and to paraphrase one of our LM trial investigators, the CNSide assay is a "game changer" for LM disease diagnosis and monitoring. And therefore, it's obviously quite synergistic with our therapeutic approach. The company that developed the test Biocept, those has been in financial distress throughout 2023 and declared their insolvency earlier this month. I want to make it clear that the company's financial distress was not in any way based on the quality of the utility of the assay, but upon a variety of unrelated factors. However, prior to Biocept's announcement and because of this very concern, Plus successfully completed the transfer of all proprietary materials [Technical Difficulty] and equipment from Biocept to use the CNSide assay.

And now as per our plan, we're the test to no longer be commercially available to us, as it is not now, Plus can now begin CSF tumor cell enumeration testing limited to the ReSPECT-LM trial patients. Separately, we will consider whether to exercise the exclusivity option that we have which is exercisable through the end of 2024 under the current license. In the meantime, we'll monitor the insolvency proceedings closely. Now back to our LM trial. We plan to initiate dosing in Cohort 5 this quarter pending DSMB approval. In terms of next step for ReSPECT-LM, we will continue to focus on enrollment, site on-boarding, data assessment and planning for next steps, including Phase II. In terms of our pediatric trial, we continue to make steady progress in initiating our first in child pediatric brain cancer trial.

Travel initiation is behind our original schedule as the FDA has required substantially more supporting data from us, particularly from our ongoing trials. We had a positive follow-up meeting in Q3, and all FDA requests are both reasonable and satisfactorily addressable within the next quarter. Thereafter, pending IND clearance from the FDA anticipated to be in early 2024, we plan to initiate the Phase I ReSPECT pediatric brain cancer trial for pediatric patients with the ependymoma and high-grade glioma at Lurie Children's Hospital in Chicago. Our other novel radiotherapeutic Rhenium-188 nanoliposome biodegradable alginate microsphere or BAM for short continues to make regulatory development progress. As a reminder, BAM is a radioembolization compound designed to treat a variety of solid organ tumors.

We recently received feedback from the FDA regarding its regulatory designation and the BAM radioembolic product will be regulated as a device, primarily by CDRH. We view this as very good news as the clinical requirements and timeline for approval will be reduced in existing reimbursement paths are already in place. Our 2024 corporate goals for BAM will include specific guidance for development based on FDA -- the FDA regulatory decision. Now in terms of drug production, behind the scenes, we continue to expand and shore up existing supply agreements and work to build in across-the-board supply chain redundancy, including as it relates to isotope availability. As we complete new agreements or relationships, we will communicate those. And with that, I'll turn the call over to our Chief Financial Officer, Andrew Sims, who will review the financials.

Andrew?

Andrew Sims: Thank you, Marc. Good afternoon, everyone. Please refer to our press release issued earlier today for a summary of our financial results for the third quarter ended September 30, 2023. As of September 30, 2023, cash and cash equivalents were $11 million, which is in line with the balance at June 30, 2023. In addition, as of today, Plus has met the requirements to receive the next cash advance from CPRIT of $3.3 million, which we expect to receive prior to reporting our 2023 full year results. Plus also remains on track to receive additional advances in 2024, amounting to a further [Technical Difficulty] to a total of $10.2 million incremental non-dilutive cash grant funding is expected between today and December 31, 2024 from CPRIT.

In addition, the company continues to benefit from the 3 million grant from the NIH to support the GBM trial through Phase II, which is expected to be fully utilized by the end of 2024 to coincide with the completion of the ongoing Phase II trial. Based on the cash on hand and committed grant funding, our current balance sheet provides runway well into 2025. In addition, the company continues to be aggressive in the pursuit of additional NIH and separate grants to support both our current and planned future programs. Our practice will be to continue to announce those upon award. The company recognized $1.2 million of grant revenue in the third quarter of 2023 and $3.6 million year-to-date 2023. The company forecasts grant revenue of between $1 million to $1.5 million in Q4 2023 and between $6 million to $7 million for calendar year 2024.

Total operating expenses for the third quarter of 2023 decreased by $0.7 million to $4.5 million in 2023. Compared to total operating expenses of $5.2 million for the same period the prior year. The decrease is due primarily to the completion of the CGMP drug development in 2022. Other income totalling 32,000 for the quarter includes 119,000 of interest income, which fully offsets the interest expense on the remaining principal on the Oxford debt. So with the grant support our existing go-forward burn is close to 500,000 over the next 18 months. Net loss for the third quarter of 2023 was $3.2 million or $1 per share compared to a net loss of $5.2 million or $2.85 per share for the same period of the prior year. Now I'll turn it back to you Marc.

Marc Hedrick: Thank you, Andrew. Before we move on to Q&A, I'll take a moment to provide guidance on anticipated milestones over the next 14 months. First of all, in Q4, we have multiple presentations accepted at the SNO Annual Meeting, November 15 to 19 in Vancouver. We're particularly excited to present the first data cut from the ongoing Phase II GBM trial to be accompanied [Technical Difficlty] at our thought leader panel and we'll put out the specifics about that panel when finalized. Also the SNO annual meeting in November, we will also have an update on our LM trial as well. Looking beyond the SNO meeting and looking forward into 2024, we intend to complete enrollment in the Phase II ReSPECT-GBM trial and finalize a pivotal trial design with the FDA.

We also intend to complete enrollment in the Phase I ReSPECT-LM trial and begin the Phase II trial. We also intend to complete internal implementation of the CNSide cerebrospinal fluid tumor cell enumeration assay that has been currently utilized in the ReSPECT-LM clinical trial. We intend to obtain FDA IND approval and initiate the Phase I ReSPECT pediatric brain cancer trial for pediatric patients with ependymoma and high-grade glioma at the Lurie Children's Hospital in Chicago. We also will complete key development milestones for the company's next-generation radioembolic device, 188RNL-BAM. At a key second source, GMP supply chain partner to support late stage clinical trials of commercial supply and publish the ReSPECT-GBM Phase I data in a peer-reviewed publication.

Now with that I'll turn it back to Tawanda, the operator for our Q&A session.

Operator: Thank you. [Operator Instructions] Our first question comes from the line of Justin Walsh with Jones Trading. Your line is open.

See also 30 Most Stressful Jobs in the US and 30 Most Polluted States in the US.

To continue reading the Q&A session, please click here.