SBIR-STTR Award

Glioblastoma (GBM) is the most common primary brain tumor, and one of the deadliest forms of cancer. Standard surgery, chemotherapy, and radiation fail to eliminate the infiltrative, invasive cancer cells. Median survival remains only ~15 months. Drugs that seek out the disseminated GBM cells behind the blood-brain barrier will prevent the inevitable recurrence in patients. Based on their unique tumor-tropic migration and long- term drug delivery, engineered neural stem cells (NSCs) have shown enormous promise as a new approach to GBM therapy. However, procurement of appropriate cells for NSC- based therapy has been a significant challenge. The ideal NSC would be easily isolated and autologous to avoid immune rejection. To overcome the challenges with isolating autologous NSC from the brain, we discovered that transdifferentiation (TD) creates tumor-homing drug carriers capable of regressing GBM. Using a defined set of transcription factors, we switched the fate of mouse and human skin fibroblasts in induced NSCs (iNSCs) that homed to GBM with the same directionality as brain-derived NSCs. iNSCs genetically engineered to release the cytotoxic gene products dramatically reduced human GBM xenografts in mice and markedly extended median survival. Falcon Therapeutics now proposes to take the critical translational step. The objective of this proposal is to investigate this novel approach to cancer therapy using iNSC-based carriers from GBM cancer patient fibroblasts (iNSCPD). We will explore the following specific aims: 1) Determine if engineered iNSCPD are safe drug carriers that migrate to recurrent human GBM foci; 2) Determine if intracavity iNSCPD therapy is an effective treatment for post-surgical patient-derived GBM. This will be accomplished using a new TD approach we discovered that generates iNSCPD fast enough for clinical GBM therapy. We will use iNSCPD variants we developed that express optical reporters and/or prodrug/enzyme therapies that mimic clinical NSC therapy for GBM. We will employ our unique models of GBM resection/recurrence in mice and transplant iNSCPD on our newly identified clinically- compatible matrices to maximize the clinical relevancy of our findings. Once complete, our studies promise to identify a new approach to autologous NSC therapy that is easily translatable to human patient testing. This will address a critical gap in current NSC-based treatments for GBM, serve as a springboard for the field of iNSC-based carriers to improve cancer treatment, and begin to move this promising therapy towards clinical trials as well as commercialization.

Public Health Relevance Statement:
PROJECT NARRATIVE Glioblastoma (GBM) is an incurable brain cancer where ineffective drug delivery results in rapid disease progression and patient mortality. Building on preliminary evidence from mouse and human cells, this proposal seeks to characterize cytotoxic neural stem cells derived from GBM patient skin fibroblasts as a new approach to personalized GBM therapy. These studies could allow practical, safe, and efficacious personalized NSC- based therapies for GBM to become a reality, and launch the field of patient-specific NSC therapies towards improving cancer treatment.

NIH Spending Category:
Biotechnology; Brain Cancer; Brain Disorders; Cancer; Neurosciences; Orphan Drug; Rare Diseases; Stem Cell Research; Stem Cell Research - Induced Pluripotent Stem Cell; Stem Cell Research - Induced Pluripotent Stem Cell - Human

Project Terms:
Address; Adult; Allogenic; Animals; Antibodies; Autologous; base; Biological; bioluminescence imaging; Biopsy; Blood - brain barrier anatomy; Brain; brain cell; Bypass; cancer cell; cancer invasiveness; Cancer Patient; cancer therapy; Cancerous; Cell Differentiation process; Cell Therapy; cell type; Cells; chemotherapy; Clinical; Clinical Trials; clinically relevant; commercialization; cytotoxic; Cytotoxic agent; Deposition; Diffuse; Disease Progression; Drug Carriers; Drug Delivery Systems; effective therapy; efficacy testing; Engineering; enzyme therapy; Excision; Fibroblasts; gene product; Genetic; Genetic Engineering; Glioblastoma; Home environment; Homing; Human; Immune; Implant; improved; in vivo; innovation; killings; Malignant neoplasm of brain; Malignant Neoplasms; Methods; migration; Modeling; Molecular; Monitor; mortality; mouse model; Mus; nerve stem cell; new technology; novel strategies; Operative Surgical Procedures; Optical reporter; Patients; Pharmaceutical Preparations; pluripotency; Postoperative Period; preclinical efficacy; prevent; Primary Brain Neoplasms; Prodrugs; Property; Radiation; Recurrence; Reducing Agents; research clinical testing; Residual Cancers; Risk; Safety; scaffold; Skin; Skin Cancer; Solid; Source; standard of care; stem cell technology; stem cell therapy; Stem cells; Surgically-Created Resection Cavity; Teratoma; Testing; Therapeutic; Tissues; transcription factor; transdifferentiation; Transplantation; Treatment Efficacy; tumor; Tumor-Derived; Variant; vector; Work; Xenograft procedure

Glioblastoma (GBM) is an intractable cancer with an average survival time of 12 to 15 months. Treatment options are limited by the infiltration of tumor cells into healthy tissue and the difficulty of delivering effective chemotherapeutics across the blood brain barrier, but engineered neural stem cells (NSCs) hold great promise as GBM therapies because they selectively migrate to tumor cells and can be modified to deliver chemotoxic agents directly to those cells. The concept has been demonstrated in multiple studies, and several clinical trials are underway with engineered human allogenic NSCs. However, the use of allogenic cells requires immunosuppression and may reduce the persistence and efficacy of the treatment. Engineered autologous NSCs could overcome these challenges and further improve the efficacy of this technology. With the support of a previous Phase I STTR award, Falcon Therapeutics Inc. and Dr. Shawn Hingtgen at the University of North Carolina—Chapel Hill used a novel transdifferentiation (TD) strategy to develop the first induced NSC-based drug carriers derived from the skin of patients with GBM (iNSCTE). Falcon demonstrated that 1) its single-factor SOX2 TD strategy converted human skin fibroblasts into tumor-homing early-stage induced NSCs (h-iNSCTE); 2) h-iNSCTE rapidly migrated to human GBM cells and penetrated human GBM spheroids without inducing stem-cell based tumors; 3) h-iNSCTE thymidine kinase/ganciclovir enzyme/prodrug therapy (h-iNSCTE–TK) reduced the size of patient-derived GBM xenografts by 95% and extended survival from 32 to 62 days; and 4) h-iNSCTE–TK therapy delivered into the postoperative GBM surgical resection cavity delayed the regrowth of residual GBMs and prolonged survival from 28 to 62 days. These results demonstrated that TD of human skin into h-iNSCTE is a viable platform for creating tumor-homing cytotoxic cell therapies for cancer, where the potential to avoid carrier rejection could maximize treatment durability in human trials. The studies proposed in Phase II will advance h-iNSCTE–TK therapy to the pre-IND stage: Aim 1) Develop a cGMP-compatible process for h-iNSCTE–TK production; Aim 2) Conduct an IND-enabling toxicity, biodistribution, and tumorigenicity study in immunodeficient NSG mice; and Aim 3) Determine the efficacy of intracerebroventricular re-dosing of h- iNSCTE–TK in human GBM xenografts. Phase II metrics of success are to 1) develop a safety package that will be submitted to the FDA as part of an IND filing and 2) confirm the efficacy h-iNSCTE–TK therapy re-dosing in a clinically relevant setting. The Phase II mechanism is appropriate based on a) successful completion of Phase I milestones and demonstration of the mechanism of action and in vivo safety and efficacy, b) the fact that multiple Phase I clinical tests have shown the safety of allogeneic NSCs, and c) the dire need for an FDA- approved product to improve survival outcomes for GBM. The study will support further clinical development of this innovative, high impact approach to autologous iNSC therapy.

Public Health Relevance Statement:
PROJECT NARRATIVE Glioblastoma (GBM) is an incurable brain cancer where ineffective drug delivery results in rapid disease progression and patient mortality. Building on successful prior work in mouse and human cells, this project is designed to develop cytotoxic neural stem cells derived from GBM patient skin fibroblasts as a new approach to personalized GBM therapy. These studies could allow practical, safe, and efficacious personalized neural stem cell-based therapies for GBM to become a reality and launch the field of patient-specific neural stem cell therapies towards improving cancer treatment.

NIH Spending Category:
Biotechnology; Brain Cancer; Brain Disorders; Cancer; Neurosciences; Orphan Drug; Rare Diseases; Stem Cell Research; Stem Cell Research - Nonembryonic - Human; Transplantation

Project Terms:
acute toxicity; Allogenic; Animals; Autologous; Avastin; Award; base; bevacizumab; Biodistribution; Blood - brain barrier anatomy; Brain; cancer cell; Cancer Patient; cancer therapy; Cell Therapy; Cells; chemoradiation; Clinical; clinical development; Clinical Trials; clinically relevant; Collaborations; Cyclic GMP; cytotoxic; Cytotoxic agent; Deposition; design; Development; Diagnosis; Diffuse; Disease Progression; Dose; Drug Carriers; Drug Delivery Systems; effective therapy; Engineering; Ensure; Enzymes; Excision; Extracellular Matrix; FDA approved; Female; Fibroblasts; Ganciclovir; Glioblastoma; Homing; Human; Human Engineering; Immunosuppression; improved; in vivo; Individual; Infiltration; Injections; innovation; Life; male; Malignant neoplasm of brain; Malignant Neoplasms; manufacturing process; Monitor; mortality; mouse model; Mus; Natural Killer Cells; neoplastic cell; nerve stem cell; North Carolina; novel; novel strategies; Operative Surgical Procedures; Palliative Care; Patients; Phase; Phase I Clinical Trials; Postoperative Period; preclinical trial; Procedures; Process; Prodrugs; Production; Publishing; Recurrence; Residual state; response; Safety; Signal Transduction; Skin; Small Business Technology Transfer Research; Solid; Stem Cell Development; stem cell therapy; Stem cells; success; Surgically-Created Resection Cavity; survival outcome; symptom management; Technology; Testing; Therapeutic; Thymidine Kinase; Time; Tissues; Toxic effect; transdifferentiation; Transplantation; Treatment Efficacy; tumor; Tumor-Derived; Tumorigenicity; Universities; Work; Xenograft procedure