Central nervous system (CNS) cancers remain among the most difficult diseases to treat in oncology, with limited therapeutic options, complex delivery challenges and poor patient outcomes continuing to hinder progress. As interest in targeted radiotherapeutics accelerates across the biopharma industry, companies are increasingly exploring more precise approaches capable of overcoming barriers such as the blood-brain barrier and diffuse tumor spread. In this exclusive interview with Biopharma Boardroom, Dr. Marc Hedrick, CEO of Plus Therapeutics, explains how the company’s investigational radiotherapeutic REYOBIQ™ is designed to deliver localized radiation directly within the CNS, the strategic importance of recent regulatory and reimbursement milestones, and how integrated diagnostic platforms like CNSide® could help transform treatment decision-making and healthcare economics in neuro-oncology.

Plus Therapeutics is advancing targeted radiotherapeutics for highly challenging CNS cancers such as leptomeningeal metastases and recurrent glioblastoma. From your perspective, what differentiates REYOBIQ™ in terms of both mechanism and clinical potential compared to existing treatment approaches?

REYOBIQ™ is fundamentally differentiated by our approach to both delivery and control of radiation within the central nervous system (CNS), which remains one of the most challenging environments in oncology. Traditional systemic therapies are limited by the blood-brain barrier, and external beam radiation is constrained in its ability to safely treat diffuse or infiltrative disease.

Mechanistically, our platform is designed to overcome these limitations through localized administration of a targeted radiotherapeutic directly into the CNS, enabling radiation to be delivered where the disease resides. REYOBIQ combines the radioisotope Rhenium-186 with a nanoliposome carrier engineered to enhance retention at the site of administration and limit systemic dispersion. This allows radiation to remain concentrated in tumor tissue for a longer duration, rather than clearing rapidly.

With the recent Orphan Drug Designation from the FDA for pediatric malignant gliomas, how does this milestone shape your clinical development and commercialization strategy, particularly in rare and underserved patient populations?

The Orphan Drug Designation is an important milestone and validation of both the unmet need in pediatric malignant gliomas and the potential role REYOBIQ could play in addressing it. REYOBIQ’s ability to deliver high-dose radiation precisely to tumor sites while minimizing exposure to healthy brain tissue has the potential to meaningfully improve outcomes for the underserved patient population. From a development standpoint, it provides us with regulatory incentives, including the potential for seven years of market exclusivity, that support continued investment in these rare indications.

Strategically, the Orphan Drug Designation reinforces our focus on underserved CNS cancers where innovation has lagged and where targeted radiotherapeutics may offer a differentiated benefit. It also enables more efficient engagement with regulators as we design clinical programs tailored to smaller patient populations. From a commercialization perspective, orphan indications often require a more focused, highly specialized approach, and we are building our strategy accordingly, prioritizing centers of excellence, physician education, and evidence generation that clearly demonstrates clinical and economic value.

The addition of a Category III CPT code for convection-enhanced delivery is a notable step forward. How important is reimbursement infrastructure in unlocking adoption for innovative therapies like REYOBIQ™, and what are the next steps toward broader market access?

Reimbursement is a foundational component of bringing any innovative therapy to patients, particularly for procedure-based treatments like targeted radiotherapeutics. The establishment of a Category III CPT code for convection-enhanced delivery used in the administration of REYOBIQ for adult recurrent glioblastoma and pediatric brain cancer is an important step because it creates a pathway to capture utilization, standardize procedures, and build the evidence base needed for broader reimbursement. For therapies like REYOBIQ, which rely on precise delivery techniques, having that infrastructure in place is essential.

Our focus now is on generating robust clinical and health economics data to support long-term coverage decisions. This includes demonstrating not only clinical benefit, but also how localized, targeted therapies may reduce downstream costs associated with disease progression and repeated interventions.

We are also working closely with providers to ensure that the operational aspects of delivery, coding, and reimbursement are aligned, which is critical for adoption in real-world clinical settings.

CNSide Diagnostics appears to play a critical role in enabling earlier and more precise detection of CNS metastases. How do you see the integration of diagnostic platforms like CNSide® shaping treatment decision-making and outcomes in neuro-oncology?

Diagnostics like CNSide are foundational to advancing care in neuro-oncology. One of the longstanding challenges in CNS cancers, particularly leptomeningeal metastases, has been the inability to reliably detect, quantify, characterize, and monitor tumor cells in the cerebrospinal fluid. CNSide addresses this gap by providing a more sensitive assessment versus the standard of care, CSF cytology.

The integration of a platform like CNSide also enables the ability to monitor treatment response over time. This has direct implications for treatment decision-making, allowing clinicians to initiate therapy sooner, adjust treatment based on real-time data, and better understand disease progression. Importantly, it also complements our therapeutic programs by helping to identify appropriate patients and measure treatment impact more precisely.

The recent health economics data suggesting a potential ~40% reduction in LM-related healthcare costs is particularly striking. How do you anticipate this type of evidence influencing payer engagement and broader healthcare system adoption?

In CNS cancers, particularly leptomeningeal metastases (LM), the economic burden of late-stage disease is substantial, driven by hospitalizations, repeat procedures, and rapid clinical decline.

Plus Therapeutics is presenting a new health economics study at ISPOR 2026, evaluating the economic impact of earlier detection and therapeutic management of LM using the CNSide cerebrospinal fluid (CSF) assay. The study observed that late-stage LM diagnosis is associated with substantial healthcare costs, including median inpatient admissions of ~$20,000. Total LM-related costs may exceed $100,000 per month, driven by repeated imaging, LM-directed therapies, and palliative care. Health economics data suggesting a potential reduction in overall costs may reduce overall LM-related healthcare costs by ~40%. This underscores an important point in this care continuum: earlier and more precise intervention can change not just outcomes, but the cost trajectory of care.

For us, this type of evidence is critical in discussions with payors. It supports the idea that investing in more advanced diagnostics and targeted therapies upfront may reduce the need for more intensive and costly care later on. As we continue to generate data, we see health economics playing an increasingly important role in aligning clinical innovation with payer priorities, particularly in complex and resource-intensive diseases like CNS cancers.

Looking more broadly, the radiotherapeutics field is gaining renewed momentum. What key trends do you see shaping the future of targeted radiation therapies, and where does Plus Therapeutics aim to lead in this evolving landscape?

We are seeing a meaningful shift in radiotherapeutics toward greater precision, localization, and integration with other technologies. One of the most important trends is the move away from broadly applied radiation toward targeted, biologically informed approaches that can be delivered directly to the tumor environment. Advances in drug delivery, particularly those that bypass the blood-brain barrier, are central to this evolution.

At the same time, there is growing recognition that therapeutics and diagnostics must evolve together. The ability to accurately detect disease, guide treatment, and monitor response is essential to realizing the full potential of targeted therapies.

At Plus Therapeutics, our goal is to lead at this intersection by combining targeted radiotherapeutics and integrated diagnostics into a fully integrated, end-to-end solution to address some of the most difficult-to-treat cancers. CNS oncology is a space where these challenges are some of the most pronounced, and where we believe our approach can have the greatest impact.