PSTV - Plus Therapeutics Inc. (PSTV) Q1 2023 Earnings Call Transcript

2023-04-20 22:30:04 ET

Plus Therapeutics, Inc. ( PSTV )

Q1 2023 Earnings Conference Call

April 20, 2023 17:00 ET

Corporate Participants

Marc Hedrick - President and Chief Executive Officer

Norman LaFrance - Chief Medical Officer

Andrew Sims - Chief Financial Officer

Conference Call Participants

Justin Walsh - Jones Trading

Sean Lee - HC Wainwright

Edward Woo - Ascendiant Capital

Presentation

Operator

Good afternoon, ladies and gentlemen. Welcome to the Plus Therapeutics First 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 in 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.

Marc Hedrick

Thank you, Jonathan. Good afternoon, everyone, and thank you once again for taking the time to join us today as we provide an overview of recent business highlights and discuss our 2023 first quarter financial results.

Joining me for the call today is Dr. Norman LaFrance, our Chief Medical Officer, and Andrew Sims, our Chief Financial Officer. I'll begin the call by reviewing our recent clinical and regulatory progress with the focus on the first quarter, and then turn the call over to Andrew to review our financials. Dr. LaFrance then will be joining us for Q&A.

I can say we had a very productive start to 2023 highlighted by the increased enrollment momentum of our two lead programs in glioblastoma or GBM and Leptomeningeal Metastases or LM. Starting with our GBM program and the Phase 2b trial, we are actively enrolling the Phase 2b clinical trial of Rhenium obisbemeda in patients with small to medium sized GBM tumors with a 20-centimeter a 20 cc or 20 milliliter cut off. The single administered dose is 22.3 millicuries and 8.8 MLs. And the primary endpoint is overall survival and there are a number of typical such secondary endpoints such as safety, objective response rate, partial response, and PFS at six months.

Our goal is to complete Phase 2b enrollment of 31 patients by the end of 2024 and we are on schedule to do that. The trial is substantially funded by the National Cancer Institute at present for up to 55 patients at five sites. We are in the process of negotiating with the NIH to expand the trial sites to a number sufficient, such that we can rapidly complete the Phase 2b and a presumed Phase 3 pivotal trial thereafter.

In parallel to our discussions with the NIH, we are actively engaged with over 17 sites in the U.S. and Europe as possible new trial sites, and we are pleased with the interest we see in that trial.

Now regarding the ongoing Phase 1 GBM dose escalation trial for larger and more complex tumors over 20 ccs. As announced, we have now enrolled the three required dose escalation patients in cohort 8 and administered a dose of 41.5 millicuries in 16.3 milliliters. That dose and volume are approximately double the dose and volume used in the current Phase 2b.

In total since trial initiation, 27 patients have been enrolled in just the Phase 1 dose escalation portion of the trial. Since we have yet to reach a Phase 1 trial stopping point based on reaching a maximum tolerated dose, we have several options in terms of how we may proceed. We are in the process of analyzing the data from cohort seven and eight from the Phase 1 and intend to provide guidance on next steps once the data is analyzed and a plan is formulated.

Now a bit of a side notes or perspective on this Phase 1 dose escalation portion of the trial. Irrespective of whatever we do in terms of next steps, I want to highlight the fact that we are breaking new ground in medicine here with this trial. Specifically, if you look in terms of the amount of radiation and volume that we are now safely delivering to a single cerebral hemisphere, in a patient that may have a tumor of 30 ccs or more, it's truly remarkable that we've been able to do that safely including administering up to 740 gray in a single administration administered dose to the tumor. Don't want that to be lost here and we haven't reached a maximum tolerated dose.

So moving on to the LM development program. As announced, we completed Part A of the Phase 1 ReSPECT LM trial. In total thus far, have been treated across three dosing cohorts and in fact, one patient was retreated under compassionate use protocol. The maximum administered dose thus far, and that was administered in cohort 3 is 26.4 millicuries up from 6.6 millicuries that were delivered in three patients in Cohort 1. At the Cohort 3 dose, the computed maximum absorbed dose to the CSF is approximately 200 gray radiation.

Thus far, no dose limiting toxicities has been observed and the safety profile as is in our GBM trial appears to be favorable. In nine of the 10 LM patients treated thus far remain alive. The go forward plan is to conduct a Cohort 3 DSMB meeting, followed by an FDA Type C meeting to finalize the dosing regimen for Part B of the Phase 1 as requested by the FDA during our original negotiations for the trial. Presumably we will continue to dose escalate through a single administration until a maximum tolerated dose is reached, and then incorporate multiple doses over time thereafter. It's helpful to us to be able to have already treated one patient under compassionate use with two separate treatments.

Separately, we're working on a single institution leptomeningeal metastases trial specifically for melanoma primaries, and more about that as that develops. In addition, we plan to treat patients with the cohort 3 dose to gain additional safety and efficacy data until cohort 4 is approved. And we will consider as I mentioned selectively retreating patients after the stipulated trial follow up period of 90 days if patient and their physician feel it would be [Technical Difficulty].

As with the GBM trials, we are focused heavily in 2023 onboarding new LM trial sites for the Phase 1 part B, and 20 sites are currently under evaluation. Finally, Plus continues to receive support for the program through our $17.6 million CPRIT grant awarded last year.

Now regarding our development program for pediatric brain cancer. Based on the back-and-forth communication we've had thus far with the FDA, which goes back almost a year, we expect to submit an updated investigational new drug application soon for what will be called the ReSPECT PBC Phase 1 safety dose finding and efficacy study of rhenium obisbemeda for two pediatric brain tumors, specifically at ependymoma and high-grade glioma.

The FDA has essentially signed off on the clinical trial plan, but they've asked for additional safety data from the human trial, which we've put together and will be refiling as part of that IND update. That will be submitted in conjunction with the lead academic institution that we've been working with along the way on this trial and that's Lurie Children's Hospital of Northwestern University in Chicago.

Now a bit about supply chain, it's very important that we have drug available for any patient we treat and that we're at a stage appropriate to where we are in the development clinically as it relates to our supply chain. So maintaining a robust and redundant supply chain for rhenium obisbemeda supply is critical. In previous quarters, we have added key suppliers and consummate an impact CMO relationships as we have developed GMP drug for our trials. We anticipate continuing in 2023 to expand those relationships and in fact add new relationships such that we are ready for a potential Phase 3 trial, or alternatively an accelerated approval tract, if that presents itself.

Now a bit about commercial planning, commercial go-to-market planning, including relevant medical economic research, billing and coding considerations and ultimately, drug pricing and commercial launch planning decisions are proceeding in the background consistent with our stage of development.

Now regarding our novel in licensed radio embolic microparticle technology RNL BAM. Recall that in 2022, we closed the license for RNL BAM, transferred the technology, successfully manufactured the product, and completed product feasibility work in a human ex vivo kidney perfusion model. We also sought the FDAs opinion on regulatory designation at the end of 2022. Currently, we have an active dialogue ongoing with the FDA, including a previously submitted preliminary request for designation.

The outcome of that determination will dictate many of the next steps in the preclinical development program, and the timeline to the clinic, specifically, whether that ultimate designation is a device, drug or combination product, notably the legacy products that have been out for 20 plus years, our devices, we think likely this should be regulated as a drug, but we await the outcome of that back-and-forth.

So with that summary, on our clinical development program, I'll turn the floor over to our Chief Financial Officer, Andrew Sims, who will review the financials. Andrew?

Andrew Sims

Thank you, Mark. Good afternoon, everyone. Please refer to our press release issued earlier today, for a summary of our financial results for the 2023 first quarter ended March 31, 2023. As of March 31, 2023, cash and cash equivalents were 12.7 million, compared to 18.1 million as of December 31, 2022. In addition to current cash on hand, the company benefits from grant awards of 3 million from the NIH and 17.6 million from CPRIT. The company also has discretionary, or stockholder approved access to capital from its ATM and equity line of credit of at least 49 million.

In aggregate these capital sources can provide sufficient capital to fund currently planned and anticipated activities through 2025 fully utilized. The company recognized 506,000 of grant revenue in the first quarter of 2023, which represents CPRIT share of costs incurred to fund a portion of our LM clinical program. Total operating expenses for the first quarter of 2023 were 5.2 million, compared to total operating expenses of 3.9 million for the same period the prior year.

The increase is due primarily to a 750,000 licensed payment to nano TX Corp for successfully meeting a key clinical milestone and related clinical expenses due to increased enrollment in the company's lead development programs.

Interest expense decreased from 998,000, the first quarter of 2022 to 134,000 for the first quarter of 2023. This decrease reflects the continued principle pay down that commenced in November 2021 on the company's Oxford debt. Net loss for the quarter for the first quarter of 2023 was 4.8 million or $0.14 per share, compared to a net loss of 4.1 million, or $0.19 per share for the same period the prior.

Now I will turn it back to Marc.

Marc Hedrick

Thank you, Andrew.

Before we move on to Q&A, allow me to provide guidance on anticipated milestones for the remainder of 2023. Importantly, we intend to publish the respect GBM Phase 1 data in a peer reviewed journal. Second, we intend to present safety and efficacy data from the respect GBM trials in the second half of 2023 as well as present safety and efficacy data of the Phase 1 part A of the respect leptomeningeal metastases trial in the second half of 2023 as well.

We also intend to initiate Phase 1 part B of the ReSPECT LM trial in the second half of 2023, following an anticipated FDA Type C meeting mid-year. We intend to complete key enrollment and site expansion activities, as mentioned in the ReSPECT GBM Phase 2b trial, such that we can meet full trial enrollment by year end 2024.

We plan to initiate the Phase 1 ReSPECT pediatric brain cancer trial or PBC trial for pediatric patients with ependymoma and high-grade glioma. We intend to determine the appropriate FDA regulatory designation for RNL BAM technology to complete the key development activities as mentioned.

We also intend to complete preclinical synergistic drug combination studies of rhenium obisbemeda, along with systemic therapies for GBM and LM. And we intend to submit multiple grant applications in order to try to secure additional non-dilutive capital to support expansion of the company's drug development pipeline.

So at this point, now, let me turn it back over to you, Jonathan. We'll go through our Q&A session.

Question-and-Answer Session

Operator

[Operator Instructions] And I understand that we also have some questions that were pre-submitted from Justin Walsh from Jones Trading and we'll take those questions first.

Andrew Sims

Thanks, Jonathan. Justin, thank you for emailing the questions. And the first question is radiopharmaceuticals seems to be in the spotlight with notable commercial success in imaging and therapy and prostate cancer. Any comments on the evolving development landscape for radiopharmaceuticals in brain cancer? And as a follow up to that, can you remind us of the potential benefits of your approach versus molecularly targeted and/or systemic approaches in the context of brain cancer? Norman if you want to.

Norman LaFrance

Yes. Thank you. Thanks for that question, Justin. I think it gets to the core of what we're doing this very typical of radiopharmaceuticals. But what distinguishes us and de-risks our efforts based on particularly our delivery platform. Your first question was kind of the [Technical Difficulty] having commercial success. So the PSMA, and the serotonin products, lutetium products were well aware of, and they're welcome and filled an important medical need.

But I think they're very good representatives of what's required in the classic targeted systemically administered radiopharmaceuticals, where you have the extra requirement of preclinical and clinical trials to both confirm and optimize that targeting technology, the time and risk to accomplish that the money and then the package insert language that goes along with that. Again, both of these are fine products, but I'll use the serotonin for the neuroendocrine tumors, as those were developed starting in the mid-2000s. There was both the DOTATATE and DOTATOC product. Lutera is the lutetium product yttrium-90. Both had similar efficacious doses both had a common safety profile. And it was recognized during the excellent clinical trials and development for these and there was some renal toxicity.

So the community had to spend time dealing with that they did that successfully with, I think folks know the [indiscernible] that goes in at the time of administration to enhance and accelerate the renal excretion of the product. So you decrease the unnecessary absorbed dose to the kidneys, and be able to get best benefits to the targeted therapy. So that gets me to what we're doing. So the one, the common approach is, we all know radiation works very well in cancer. That's non-controversial. It's been well accepted for decades.

What we're leveraging is the well-established and I'll use GBM first and well established access to a lesion in the central nervous system by convection enhanced delivery catheters, the CD catheters, an elegant discovery by NIH in late 90s, early 2000s that have been used extensively in administrations and with the whole [Technical Difficulty] the blood brain barrier challenges, and so forth and get the appropriate chemotherapy, right where it's needed, when it's needed.

Well, these molecules typically did get there very effectively with that excellent delivery technology, but quickly also diffused away and unfortunately, didn't result in any significant improvement and how these patients were doing, despite the initial promise in some early, promising Phase one, preliminary studies.

But at the end of the day, people have recognized that the Holy Grail for delivering chemotherapy, because of those -- the way those molecules behave locally, sadly, was not realized. Because of that delivery, however, because of our formulation with a bifunctional chelated rhenium isotope, which is the rhenium 186. And I won't go into details now why that is nearly an optimal choice for a radiation therapy isotope. Bifunctionally chelated and encapsulated and [indiscernible] for durable localization after direct local regional delivery to the tumor. And I think folks have seen our presentations, they've been peer reviewed and accepted at meetings. And as Marc mentioned, we're going to be publishing the Phase 1 data in the coming weeks or submitting it for publication.

So the differentiation is, we're able to successfully get the isotope which is, what is providing efficacy to where it needs to go. And our formulation allows it to stay there through the case cycles, the physical half-life center there. So it works out very well. And your question touched on what, maybe other radiopharmaceuticals systemic therapies. They suffer some of the same challenges that the systemic chemotherapies established the blood brain barrier, challenges and so forth.

So the direct delivery and we're told by both neurosurgeons and an oncologist that that's the way to go. And in a comparable way, our direct delivery via an intra ventricular catheter, Ommaya reservoir to the subarachnoid space and leptomeningeal metastases accomplishes the same local delivery that the GBM paradigm and administration paradigm accomplishes. Hopefully that satisfies your question, Justin. Thanks.

Andrew Sims

Second question. It's great to see the addition of Northwestern Memorial Hospital as a trial site. Can you provide any color on how easy or challenging it is to onboard new sites? And then do you have a sense of how that could translate to potential commercial success down the line? And what type of sites do you imagine these assets could be administered at e.g. only top centers versus any hospital with a working radio pharmacy? Norman?

Norman LaFrance

I'll take that too. Some very good points on this. But I'd like to touch, I smile at your easier challenging for sites. I'd rather use the word, getting a sign on board is very straightforward. We have three major collaborators, that have to mesh nicely in the protocol and the various documents, we have the scope events and things like that, coordinate how the neuro oncology, neurosurgery and nuclear medicine have to collaborate, cooperate in a well-defined manner, and a well-defined sequence of events to get patients treated.

So all that's well defined in our protocols and our processes to involve a site. We're very proud at Northwestern involved. We have a number of others in the pipeline that are there. And the processes are well established to get them on board. And the contractual process is such that we have plenty of time to do that in a very effective, thorough manner.

I do have to say that the sites -- all the sites are evolving and coming out of, I call it the COVID era of staffing issues and virtual at home work and things like this. But we have found our processes and how we get folks involved and the fact that each of the three major areas that I mentioned, neurosurgery, neuro oncology, nuclear medicine, all are doing activities they typically do. We just give them a process that they're collaborating with that for particular patient, that particular well-defined points in time.

In terms of elite sites, these are the sites that you would expect. We're very pleased that we're actually getting inquiries from a lot of sites. Because we've been presenting at meetings, they hear the data, they see the data, they talk to each other, they see the tolerability and the safety of what's going on. So we have let the data speak for itself, they're coming along. And of course, there'll be the core of any future commercial success platform.

But as time goes on, and as we present more data, we're getting inquiries and interest from even, I don't want to call them non-elite sites, but the large commercial hospitals. You mentioned the radio pharmacy, the product is shipped to the site ready to use and administer. Most sites do not have an active radio pharmacy that they used to have, in prior decades, you have local large pharmacies to deliver patient ready doses for both imaging and therapy. So that will not be an issue whatsoever. And we find that the sites will, the sites we're using will be the platform for commercial launch, and by then we expect to have 20 to 40 sites in a pivotal trial, or more. So hopefully, I think that covers all that you asked in this last question. Thanks.

Andrew Sims

Questions, three. Can you provide any additional color on what we should expect from the data readouts in the second half of 2023? For example, estimates on patient numbers, et cetera.

Marc Hedrick

I'll take that. That's okay. So, yes, kind of reiterating. Justin, what I mentioned earlier, the plan for GBM is, a, to get the Phase 1 data published, that's cohorts one through six, that will be a comprehensive publication with full statistical evaluation of the data. And we've been invited by a top tier, peer reviewed journal, high impact factor to submit. So that's largely done. So hopefully, that will go well. And that will be helpful also, as Norman said, to get new sites on board, because that's peer reviewed data that we can use and in discussions with sites.

In terms of ongoing data and the Phase 1, 2, and GBM, as well as the LM trial, the plan would be to present second half of the year, coinciding, most likely with the Society for Neuro oncology meetings. We had a podium presentation there last November. And the plan would be to present there as well update both Phase 1, Phase 2 for GBM, as well as present the Phase 1 Part A trial from LM.

And I think the second part of the question was estimate enrollment. So what our plan I mean, this is not a 5000 patient, any hypertensive trial. Our plan here is to, we've got a timeline in place to get to Phase 2, for example, enrolled in by the end of 2024, perhaps a bit ahead of schedule, we'll provide guidance on quarterly calls us to whether we're on schedule or not, if something materially happens, it's better or worse, we'll mention that. However, my preference is not to present specific patient numbers, in the absence of the data itself. And so, for example, it's no we'll update in terms of trial numbers, or when we hit a major milestone in terms of enrollment, we'll announce that or discuss that, but not on our earnings call to present individual patient numbers.

As it relates to the LM trial, we'll continue our present current practice, which is to present when we hit major regulatory milestones or cohort enrollment milestones, we'll announce those. But that will be more frequent, likely as we hit each milestone. So that's the plan and we will update folks accordingly.

Andrew Sims

Last question from Justin. Based on your updates, you're obviously keeping pace with enrollment. Can you comment on investigator and patient enthusiasm that you've encountered?

Norman LaFrance

Justin, as Marc mentioned, enrollment is going well, that's always nice to see. But I think it's everyone on the call might appreciate. It's all about getting sites and making sure we expand those sites. And Marc has also mentioned our plans to do that in a soundtrack, depending on how we, what we hear from FDA and the rapidity of the Phase 2 enrollment, the number of sites we had will be within the scope of what we have to perform for the agency feedback.

And I liked the way you ask this, you ask about both investigator and patient enthusiasm and we're getting both, and I think it's really important to emphasize that. And I'll give you maybe a couple of quick examples. What we consistently get from the investigators, and I think, folks now I have a Hopkins heritage, and I know a lot of folks there. And at the recent SNO meeting, Skip Grossman got the neuro oncologist, had there -- cut past colleague of mine, and got the Lifetime Achievement Award. And he saw our presentation on LM. And we know each other, and we got to speaking and his comment, paraphrase is, these LM patients really have nothing. And we're very motivated to get involved in this trial. And, for example, that's one of the sites and something that one of the person I respect and I think is well-known in the field and respected by others have recognized.

And we've gotten this in many different ways. I can give you other institutions and names that have presented a similar plea and an observation of the peer review data we have presented. Equally important are the patients we've done. And I sometimes go to sites, particularly when the site asks for my involvement for just a second set of eyes and ears that there is newer site. Or maybe it's a difficult patient to be just an observer. But to put it in some perspective, more than once the patients have said, I'm grateful for this opportunity, and this option, I have no other options. And one, they've gone through it, and we've heard some follow up, it's -- I didn't realize that it was this easy. And what they've asked both Marc and I is, is there a way that I can participate in communicating to other patients, what I've experienced, and how I feel about it in some way, that's acceptable.

And I think I'm going to embarrass Marc now and give you a specific example, on the site on a patient, on GBM patient, who had your typical GBM complications, he had difficulty walking, and other things, I won't go into that detail. And lamented about having to drop out of his senior softball league and so forth. To make a long story short, within about two to three weeks after his treatment, he was back to playing softball. He asked me to send him pictures of his treatment, because as everyone knows, we have real-time evaluation because of the simultaneous gamer. So we're able to very accurately validate where the treatment goes. So in this patient's case, he wanted to be able to have that. He has his own website, things and he was kind of commenting to folks who know his challenge, of the success he has. And to make a long story short, he again raised the question about, is there a way that I can share my story, and we're in the process of doing that. And part of sharing that story is, 5k, this gentleman will be running next month. And I think our esteemed Chief Executive Officer will be running the 5k with him. So Marc, I'm sorry, it will embarrass you. But I figured this is a prime example of how not only the investigators but to patient enthusiasm for this product has really been very gratifying for me both personally and professionally. So thank you, Justin, for that.

Marc Hedrick

Okay, Jonathan. I think Justin got his money's worth on those questions. So who do we have next?

Operator

Certainly. Then our first question from the phone line comes from the line of Sean Lee from HC Wainwright. Your question please.

Sean Lee

My first question is on the GBM side. I know you mentioned that the study for treating larger tumors has been going well, and you will be able to test the higher doses of RN. I was wondering whether it's something that you consider roll into your potential future Phase 3 in GBM, or would you keep the two separate, like the regular dose and higher dose?

Marc Hedrick

It depends on the data. I think, as I mentioned, we're in the process of analyzing cohort 7 and 8. An important part of that is looking at the distribution, the effect of increasing volume and radiation. And I think as you probably -- I'm sure you do know, Sean back in cohort six, we actually increased the flow rate from the first three patients to the second three patients in cohort 6.

So there are a lot of levers we can pull. I wouldn't rule anything out at this point. But we would just say to kind of finish. We're going where no man has gone before in terms of volume, we're putting in the brain, the amount of radiation, there's real value and continuing do patients and tweaking the delivery parameters. And our plan is to continue to do that. And that's what FDA wants, and I think that's what the NCI wants.

Sean Lee

I see. Thanks for your thoughts on that. My second question is on the LM study. You mentioned that you were testing in particular looking to with melanoma patients, that's one way why melanoma is and if there's something you see or you think, in other cases, you that makes it particularly well suited for [end treatment] [ph]?

Norman LaFrance

Let me take that one. And I appreciate that question. Because it brings up another aspect of LM, which we -- I think folks on the phone know, can be caused from any solid tumor, any -- many of the liquid tumors and even the primary brain tumors. Of course, the most prevalent, breast, lung, GI, head, neck, and melanoma are most frequent. Regulatory requirements by FDA typically require and they've said this much will be what I call a disease specific indication. So going forward, given the most likely etiologies for LM, our lung and breast, I would see us in our current protocol is written with that focus, although our initial dose escalation, we do have it with all comers. But regulatorily, we will have to focus it on the disease specific way and pick the ones that would target the most people that we can help.

Melanoma is an example of another disease indication. But the reason we're splitting that out is because it's a more difficult complication. And melanoma has shown some systemic therapeutic effects, particularly with immunotherapy in general and checkpoint inhibitors in particular. And I won't go into the systemic therapies now. But there's a real opportunity for a combination approach for leptomeningeal treatment with our product, and a combination approach with whether checkpoints or other immunotherapy in a way that we're determining now with some select lines.

Sean Lee

Thank you. That was very helpful. My final question is on the upcoming pediatric study, just wondering whether you had to make specific adjustments to your delivery method? Because I know the uses the connection catheters, is it going to be any different than what you've done so far with adults?

Norman LaFrance

Yes, great question. And the short answer is, no, but let me give a little bit more color. I'm not known for my one-word answers. So sorry about that. It'll be the same approach. And what is interesting is the pediatric neurologist are used to for epileptic [Technical Difficulty] and evaluations. You would think, oh, my goodness, putting a catheter in a child's brain is going to be tough. Well, they're used to doing this not only with two or three or four catheters, as we're doing with adults, but 6, 8, 10 or more catheters. So the catheter and CD approach is something they're very comfortable with, they do all the time, epilepsy electrode retrace, targeting and tracing, for example.

And the only thing I would anticipate that might be different is particularly for ependymoma, some of these can be quite large volumes. And that will be something as we get into later dose escalations for those larger volumes, that we'll have to evaluate maybe differently. Marc already mentioned in the adult cohort 8, we're going to be increasing the volumes. So I would anticipate that in adult administration, although we have very tolerable infusion times, of course, depending on which dose we're using and the volume of infused 8, that I see reducing that by 50%. And I think the same possibilities for reduction and even greater reduction occurs in kids. And I already mentioned the fact that in the larger tumors, more catheters will be likely and the more catheters means the larger volumes can be given over a fixed unit of time. So does that answer your question, Sean?

Sean Lee

Yes, it does. Thank you again for taking my questions.

Operator

Thank you. One moment for our next question. And our next question comes from the line of Edward Woo of Ascendiant Capital. Your question, please.

Edward Woo

Yes, congratulations on all the progress. My question is on the CPRIT grant. Are there any restrictions to where you can look at your sites or any other requirements that you guys have when you're running these clinical trials?

Marc Hedrick

There’re no restrictions on where those clinical sites can be. There's some restrictions around having sites in Texas and so forth, and having employees and office spaces so forth in Texas, but not to in terms of sites.

Norman LaFrance

We can [bet on] [ph] restrictions.

Edward Woo

Great. Well, that's all the questions I have. Thank you.

Operator

Thank you. [Operator Instructions]. And this does conclude the question-and-answer session of today's program. I'd like to hand the program back to Dr. Marc Hedrick for any further remarks.

Marc Hedrick

Thank you, Jonathan. Appreciate the questions today and appreciate your attention. And we want to finish up by thanking our employees and patients and physicians and collaborators we work with and our stockholders for their continued support. Thank you for the questions today. And we wish you have a nice evening. Thank you.

Operator

Thank you, ladies and gentlemen, for your participation in today's conference. This does conclude the program. You may now disconnect. Good day.

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Plus Therapeutics, Inc. (PSTV) Q1 2023 Earnings Call Transcript