fbpx Our Platform - Plus Therapeutics (PSTV)

There is no question that radiation is an
effective therapy for destroying cancer.

However, with traditional approaches in radiation therapy, safely delivering high radiation doses to a single target region and keeping it there long enough to completely eliminate the tumor has been, in most cases, impossible.

We have built a radiotherapeutic platform with the potential to overcome these challenges by directing higher, more powerful radiation doses at the tumor – and only the tumor. By minimizing radiation exposure to healthy tissues while simultaneously maximizing efficacy, we hope to reduce the toxicity of radiation for patients, improving their quality of life and giving them more time to enjoy it.

The components of our radiotherapeutic platform.

Rhenium Radioisotopes

Rhenium is a versatile radioisotope (radioactive isotope) that emits beta energy with a short (90-hour) half-life and sufficient energy for destroying tumor tissue – as well as a gamma energy with photons for live imaging through the treatment process. We leverage two different radioisotopes, Rhenium-186 and Rhenium-188, which offer unique physical properties for treating various tumor sizes and types.1

Rhenium-186

Nuclear reactor-produced 1.8 mm average radiation path length of beta energy Suitable for treating small and medium tumors

 

Rhenium-188

Generator-produced for quick availability 3.1 mm average radiation path length of beta energy Suitable for large tumors

BMEDA is a specially developed small molecule that chelates with Rhenium and enables us to efficiently load it into the interior of a nanoliposome structure.

Nanoliposomes are small, complex carriers often used for site-specific drug delivery. Through our chelation technique, we are able to successfully entrap Rhenium in a nanoliposome. Within this carrier, the Rhenium is able to reach the tumor and remain within the tissue for a period of days. Otherwise, the radioactive energy would quickly disperse and be absorbed by the circulatory system within hours.

We design nanoliposomes at 100 nanometers, the ideal size to facilitate accumulation and retention at the site of injection. As nanoliposomes are comprised of the same lipid membranes as human cells, they degrade naturally in the body, leading to less toxicity.

Radioembolization involves the direct injection of a microsphere containing radioactive isotopes into the small artery system of the vasculature (specifically the hepatic artery) to block a liver tumor’s blood supply. Some of the shortcomings with standard microspheres are that they are rigid, permanent, invisible implants (glass, resin) and stay in the liver.

How we’ve combined unique components to create highly innovative and targeted radiotherapeutics.

Rhenium-186 NanoLiposome
(186RNL)

Rhenium-188 NanoLiposome Biodegradable
Alginate Microsphere (188RNL-BAM)

Goal

186RNL

186RNL

To inject high doses of radiation into or adjacent to brain and central nervous system (CNS) cancers, which then accumulate in the tumor, break down slowly to sufficiently destroy tumor tissue, and stay localized, sparing healthy tissues until fully cleared.

188RNL-BAM

188RNL-BAM

To inject high doses of radiation into solid organ cancers such as liver cancers, blocking the tumor’s blood supply, maintaining a localized attack on the tumor and then rapidly clearing the body without damage to healthy tissue.

Composition

188RNL-BAM

186RNLAM

BMEDA-chelated Rhenium-186, encapsulated in a nanoliposome carrier.

188RNL-BAM

188RNL-BAM

BMEDA-chelated Rhenium-188, encapsulated in a nanoliposome carrier and loaded into an alginate microsphere.

Disease Targets

Delivery Method

186RNL

186RNL

For patients with GBM and PBC, the size of our nanoliposome paired with Convection Enhanced Delivery (CED) allows 186RNL to bypass the blood-brain barrier and enhance drug distribution to a target region. For patients with LM, we administer 186RNL intraventricularly through the Ommaya reservoir, directly in the CNS compartment where the tumor is located.

188RNL-BAM

188RNL-BAM

We plan to develop and offer trans-arterial radioembolization in a minimally invasive, 2-step procedure where the drug is infused through a microcatheter into the hepatic artery, inducing highly selective tumor necrosis.

Monitoring Technique

186RNL

186RNL

Live imaging of the tumor before and after administration, ensuring more accurate catheter placement and dosimetry/dosing.

188RNL-BAM

188RNL-BAM

Live imaging of the tumor before and after administration, ensuring more accurate catheter placement and dosimetry/dosing.