Advancing Targeted Radionuclide Therapy Through the National Cancer Institute's Small Business Innovation Research Pathway

Radionuclide-based theranostics - a promising strategy for lung cancer

PURPOSE

This review aims to provide a comprehensive overview of the latest literature on personalized lung cancer management using different ligands and radionuclide-based tumor-targeting agents.

BACKGROUND

Lung cancer is the leading cause of cancer-related deaths worldwide. Due to the heterogeneity of lung cancer, advances in precision medicine may enhance the disease management landscape. More recently, theranostics using the same molecule labeled with two different radionuclides for imaging and treatment has emerged as a promising strategy for systemic cancer management. In radionuclide-based theranostics, the target, ligand, and radionuclide should all be carefully considered to achieve an accurate diagnosis and optimal therapeutic effects for lung cancer.

METHODS

We summarize the latest radiotracers and radioligand therapeutic agents used in diagnosing and treating lung cancer. In addition, we discuss the potential clinical applications and limitations associated with target-dependent radiotracers as well as therapeutic radionuclides. Finally, we provide our views on the perspectives for future development in this field.

CONCLUSIONS

Radionuclide-based theranostics show great potential in tailored medical care. We expect that this review can provide an understanding of the latest advances in radionuclide therapy for lung cancer and promote the application of radioligand theranostics in personalized medicine.

National Cancer Institute support for targeted alpha-emitter therapy

BACKGROUND

Radiopharmaceutical targeted therapy (RPT) has been studied for decades; however, recent clinical trials demonstrating efficacy have helped renewed interest in the modality.

METHODS

This article reviews National Cancer Institute (NCI)'s support of RPT through communication via workshops and interest groups, through funding extramural programs in academia and small business, and through intramural research, including preclinical and clinical studies.

RESULTS

NCI has co-organized workshops and organized interest groups on RPT and RPT dosimetry to encourage the community and facilitate rigorous preclinical and clinical studies. NCI has been supporting RPT research through various mechanisms. Research has been funded through peer-reviewed NCI Research and Program Grants (RPG) and NCI Small Business Innovation Research (SBIR) Development Center, which funds small business-initiated projects, some of which have led to clinical trials. The NCI Cancer Therapy Evaluation Program (CTEP)'s Radiopharmaceutical Development Initiative supports RPT in NCI-funded clinical trials, including Imaging and Radiation Oncology Core (IROC) expertise in imaging QA and dosimetry procedures. Preclinical targeted a-emitter therapy (TAT) research at the NCI's intramural program is ongoing, building on foundational work dating back to the 1980s. Ongoing "bench-to-bedside" efforts leverage the unique infrastructure of the National Institutes of Health's (NIH) Clinical Center.

CONCLUSION

Given the great potential of RPT, our goal is to continue to encourage its development that will generate the high-quality evidence needed to bring this multidisciplinary treatment to patients.

Radioactive polymeric nanoparticles for biomedical application

Nowadays, emerging radiolabeled nanosystems are revolutionizing medicine in terms of diagnostics, treatment, and theranostics. These radionuclides include polymeric nanoparticles (NPs), liposomal carriers, dendrimers, magnetic iron oxide NPs, silica NPs, carbon nanotubes, and inorganic metal-based nanoformulations. Between these nano-platforms, polymeric NPs have gained attention in the biomedical field due to their excellent properties, such as their surface to mass ratio, quantum properties, biodegradability, low toxicity, and ability to absorb and carry other molecules. In addition, NPs are capable of carrying high payloads of radionuclides which can be used for diagnostic, treatment, and theranostics depending on the radioactive material linked. The radiolabeling process of nanoparticles can be performed by direct or indirect labeling process. In both cases, the most appropriate must be selected in order to keep the targeting properties as preserved as possible. In addition, radionuclide therapy has the advantage of delivering a highly concentrated absorbed dose to the targeted tissue while sparing the surrounding healthy tissues. Said another way, radioactive polymeric NPs represent a promising prospect in the treatment and diagnostics of cardiovascular diseases such as cardiac ischemia, infectious diseases such as tuberculosis, and other type of cancer cells or tumors.

211At-Labeled Polymer Nanoparticles for Targeted Radionuclide Therapy of Glucose-Dependent Insulinotropic Polypeptide Receptor (GIPR)-Overexpressed Cancer

Targeted radionuclide therapy (TRT) provides new and safe opportunities for cancer treatment and management with high precision and efficiency. Here we have designed a novel semiconducting polymer nanoparticle (SPN)-based radiopharmaceutical (²¹¹At-MeATE-SPN-GIP) for TRT against glucose-dependent insulinotropic polypeptide receptor (GIPR)-positive cancers to further explore the applications of nanoengineered TRT. ²¹¹At-MeATE-SPN-GIP was engineered via nanoprecipitation, followed by its functionalization with a glucose-dependent insulinotropic polypeptide (GIP) to target GIPR and deliver ²¹¹At for α therapy. The therapeutic effect and biological safety of ²¹¹At-MeATE-SPN-GIP were investigated using GIPR-overexpressing human pancreatic cancer CFPAC-1 cells and CFPAC-1-bearing mice. In this work, ²¹¹At-MeATE-SPN-GIP was produced with a radiochemical yield of 43% and radiochemical purity of 98%, which exhibited a specifically high uptake in CFPAC-1 cells, inducing cell cycle arrest at the G2/M phase and extensive DNA damage. In the CFPAC-1-bearing tumor model, ²¹¹At-MeATE-SPN-GIP exhibited high therapeutic efficiency, with no obvious side effects. The GIPR-specific binding of ²¹¹At-MeATE-SPN-GIP combined with effective inhibition of tumor growth and fewer side effects compared to control suggests that ²¹¹At-MeATE-SPN-GIP TRT holds great potential as a novel nanoengineered TRT strategy for patients with GIPR-positive cancer.

Phase 0 Radiopharmaceutical-Agent Clinical Development

The evaluation of antibody-targeted or peptide-targeted radiopharmaceuticals as monotherapy or in oncological drug combinations requires programmatic collaboration within the National Cancer Institute (NCI) clinical trial enterprise. Phase 0 trials provide a flexible research platform for the study of radiopharmaceutical–drug pharmacokinetics, radiation dosimetry, biomarkers of DNA damage response modulation, and pharmacodynamic benchmarks predictive of therapeutic success. In this article, we discuss a phase 0 clinical development approach for human antibody-targeted or peptide-targeted radiopharmaceutical–agent combinations. We expect that early-phase radiopharmaceutical–agent combination trials will become a more tactical and more prevalent part of radiopharmaceutical clinical development in the near-term future for the NCI Cancer Therapy Evaluation Program.

Feasibility and limitations of quantitative SPECT for 223Ra

The aim of this paper is to investigate the feasibility and limitations of activity-concentration estimation for ²²³Ra using SPECT. Phantom measurements are performed using spheres (volumes 5.5 mL to 26.4 mL, concentrations 1.6 kBq mL^-1 to 4.5 kBq mL^-1). Furthermore, SPECT projections are simulated using the SIMIND Monte Carlo program for two geometries, one similar to the physical phantom and the other being an anthropomorphic phantom with added lesions (volumes 34 mL to 100 mL, concentrations 0.5 kBq mL^-1 to 4 kBq mL^-1). Medium-energy and high-energy collimators, 60 projections with 55 s per projection and a 20% energy window at 82 keV are employed. For the Monte Carlo simulated images, Poisson-distributed noise is added in ten noise realizations. Reconstruction is performed (OS-EM, 40 iterations, 6 subsets) employing compensation for attenuation, scatter, and collimator-detector response. The estimated concentrations in the anthropomorphic phantom are also corrected using recovery coefficients. Errors for the largest sphere in the physical phantom range from -25% to -34% for the medium-energy collimator and larger deviations for smaller spheres. Corresponding results for the high-energy collimator are -15% to -31%. The corresponding Monte Carlo simulations show standard deviations of a few percentage points. For the anthropomorphic phantom, before application of recovery coefficients the bias ranges from -16% to -46% (medium-energy collimator) and -10% to -28% (high-energy collimator), with standard deviations of 2% to 14% and 1% to 16%. After the application of recovery coefficients, the biases range from -3% to -35% (medium energy collimator) and from 0% to -18%. The errors decrease with increasing concentrations. Activity-concentration estimation of ²²³Ra with SPECT is feasible, but problems with repeatability need to be further studied.

Radiation Biomarkers: Can Small Businesses Drive Accurate Radiation Precision Medicine?

Radiation therapy is an essential component of cancer treatment. Currently, tumor control and normal tissue complication probabilities derived from a general patient population guide radiation treatment. Its outcome could be improved if radiation biomarkers could be incorporated into approaches to treatment. A substantial number of cancer patients suffer from side effects of radiation therapy. These side effects can result in treatment interruption. Such unplanned treatment interruptions not only jeopardize anticancer treatment efficacy but also result in poor post-treatment quality-of-life. To develop and translate radiation biomarkers for clinical use, NCI's Radiation Research Program, in collaboration with the Small Business Innovation Research Development Center, funded four small businesses through the request for proposals after peer review during 2015-2019. Here, we summarize publicly available information on intellectual property rights, the status of development, ongoing clinical trials, success in obtaining financing and regulatory approval. An analysis of publicly available information indicates all four companies have completed phase I of SBIR funding and advanced to further development, validation and clinical trials with phase II SBIR funding. These biomarkers are: 1. A panel of genomic biomarkers of radiation response to predict toxicity and radioimmune response (MiraDx Inc., Los Angeles, CA); 2. A multiplex assay for single nucleotide polymorphism (SNP) biomarkers of radiation sensitivity to identify a subset of prostate cancer patients for which radiotherapy is contraindicated (L2 Diagnostics, New Haven, CT); 3. A cell-free DNA assay in blood to measure tissue damage shortly after radiation exposure (DiaCarta Inc., Richmond, CA); and 4. A metabolomic/lipidomic assay to predict late effects that adversely affect quality-of-life among patients treated with radiation for prostate cancer (Shuttle Pharmaceuticals, Rockville, MD). This work also provides a bird's eye view of the process of developing radiation biomarkers for use in radiation oncology clinics, some of the challenges and future directions.