Plus Therapeutics, Inc. Q2 FY2024 earnings call

Clinical and Corporate Progress at SNO/ASCO

• At the 2024 Society for Neuro-Oncology and combined American Society for Clinical Oncology CNS Metastases Conference, Plus had four presentations, sponsored a symposium, and participated in a panel. Dr. Andrew Brenner presented an interim update on the ReSPECT-LM trial, showing Cohort 4 of 16 patients had safe and well-tolerated dosing with no dose-limiting toxicities, high therapeutic window, and median overall survival of 12 months. Dr. Priya Kumthekar reported FORESEE trial results on CNSide diagnostic, showing >90% influence on treatment decisions, higher sensitivity than cytology for detecting tumor cells in CSF.

Leptomeningeal Program

• ReSPECT-LM Phase 1 single administration dose escalation trial continues, with plan to determine Cohort 6 at next DSMB meeting. Multiple dosing protocol submitted to FDA, anticipated start later 2024. Supported by ~$18M CPRIT grant.

Diagnostic LM Program

• Hired Dr. Greg Fuller as Medical Director of CNSide lab, improved lab QA, applied for CLIA certification.

ReSPECT-GBM Trial

• Enrolling patients, new sites to enroll (Ohio State University, North Shore Hospital), plan to update data at CNS annual meeting in late Sept/early Oct. Aim to complete enrollment by end of 2024 or first half of 2025.

Pediatric Brain Cancer Program

• Received $3M DOD award, anticipated to begin funding Sept 2024, IND approval anticipated, Lurie Children’s Hospital as initial site

Supply Chain and Drug Delivery

• Making progress behind the scenes on supply chain redundancy and drug delivery capabilities, with material updates coming soon

Key Events/Milestones

• Presentation at Congress of Neurological Surgeons in late Sept/early Oct on ReSPECT-GBM trial results.
• Three presentations at SNO 2024 in Nov: update on ReSPECT-LM trial, and two CNSide diagnostic abstracts.
• Anticipated FDA approval for LM Phase 1 multiple dose trial and IND approval for pediatric trial later in 2024

Q: Could you provide more context around the types of treatment decisions informed by CNSide?

A: Marc Hedrick discussed that CNSide informs decisions such as whether a patient has the disease, genetic drift issues, and whether to stop treatment. It helps in determining disease presence, actionable biomarkers, and potential treatment cessation based on CTC counts.

Q: What are your expectations regarding timing for the multi-dose LM portion of the trial?

A: Marc Hedrick stated the IND is open, optimistic about FDA approval, and expects the trial to start later in 2024 with sites already being prepared. Data is expected to accumulate quickly with multiple doses.

Q: What are the next steps for the CNSide assay before selling to the market?

A: Marc Hedrick mentioned hiring a Medical Director, manufacturing microfluidic chips in-house, scaling testing throughput, and conducting commercial evaluation to determine the commercial opportunity.

Q: Does it still make sense to continue the single-dose LM study to higher dose cohorts while working on the multi-dose study?

A: Marc Hedrick said the FDA is interested in determining the maximum tolerated dose, so they'll continue the single-dose study to understand toxicity, then focus on the multi-dose study and decide on next steps.

Q: Will there be more data updates from the GBM study later this year?

A: Yes, there will be a substantial update on the Phase 1 and Phase 2 data at the CNS annual meeting in late Sept/early Oct.

Q: Is there seasonality to grant funding and any change in funding availability?

A: Marc Hedrick said grant funding is seasonal, e.g., CPRIT has specific grant cycles, and they have a good relationship with CPRIT, aiming to leverage non-dilutive capital