This milestone marks the first of several solid tumor types to be dosed in the LUMINOS-103 basket trial

In its first bladder cancer cohort, Istari is testing the response to neoadjuvant PVSRIPO as a potential future solution to radical cystectomy

DURHAM, NC, USA I October 12, 2021 IIstari Oncology, Inc., a clinical-stage biotechnology company developing novel immunotherapies for the treatment of solid tumors, today announced its first patient was dosed in the company’s LUMINOS-103 bladder cancer sub-study (NCT04690699). In this sub-study, the safety and response to the company’s novel intratumoral viral immunotherapy, PVSRIPO, is being assessed as a neoadjuvant therapy with or without PD-1 inhibitors in adult bladder cancer patients who are ineligible for chemotherapy. Positive results from this sub-study may lead to a future trial to determine if radical cystectomy (removal of the bladder) could be avoided.

PVSRIPO is an investigational immunotherapy based on the live-attenuated Sabin type 1 poliovirus vaccine that has been genetically modified for safety. PVSRIPO has been shown to activate a patient’s innate and adaptive immune system to facilitate a systemic anti-tumor immune response. Because PVSRIPO utilizes CD155 (the poliovirus receptor) to enter both solid tumor cells and antigen-presenting cells (APCs) in the tumor microenvironment, it has the potential to treat a variety of cancers.

“PVSRIPO has shown impressive responses with monotherapy in patients participating in two phase 1 clinical trials focused on glioblastoma and melanoma,” said Matt Stober, president and CEO at Istari Oncology. “We look forward to further evaluating its therapeutic value as we aim to expand the potential treatment options for patients living with bladder cancer.”

LUMINOS-103 is a phase 1/2, multi-center, open-label, single-arm basket trial evaluating the administration of PVSRIPO with or without PD-1/L1 inhibitors across multiple tumor types, including muscle-invasive bladder cancer, and head and neck cancer (a sub-study that opened for enrollment in August 2021). The phase 2 LUMINOS-103 bladder cancer sub-study will be conducted at approximately 10 research sites across the U.S. It will evaluate both a neoadjuvant approach in patients with resectable disease, and separately in a cohort of patients with metastatic disease.

An analysis of each cohort comprising the LUMINOS-103 bladder cancer sub-study is planned once 25 to 30 patients per cohort have been enrolled and treated for at least two months. Study endpoints include objective response rate (by RECIST criteria), durability of response, progression and recurrence-free survival, and overall survival.

“Bladder cancer patients, particularly those who cannot receive cisplatin-based chemotherapy or who have advanced disease, are urgently in need of viable treatment options that limit systemic toxicity and improve patient outcomes,” said Dr. Neal Shore, MD FACS, U.S. chief medical officer of surgery and urology at GenisisCare US and principal investigator responsible for dosing the first patient in Istari Oncology’s LUMINOS-103 bladder cancer sub-study. “We are excited to be initiating the LUMINOS-103 sub-study at the Carolina Urologic Research Center, and we are hopeful that the promising data achieved in previous clinical studies investigating PVSRIPO in patients with glioblastoma and melanoma will translate to positive outcomes for those in the bladder cancer community.”

According to the Bladder Cancer Advocacy Network (BCAN), a national advocacy organization devoted to advancing bladder cancer research and supporting those impacted by the disease, bladder cancer most often begins in the urothelial cells that line the inside of the bladder with most tumors developing on the inner layer of the bladder. Bladder cancer becomes more difficult to treat as it grows through the layers of the bladder and into the muscle wall. Though less frequently, bladder cancer can also occur in the kidneys and ureters.1 The American Cancer Society estimates 84,000 new cases of bladder cancer in the U.S. in 2021.2

For more information about Istari Oncology and its ongoing clinical trials, visit


PVSRIPO is an investigational immunotherapy based on the live attenuated Sabin type 1 poliovirus vaccine that has been genetically modified for safety. PVSRIPO targets cells using the poliovirus receptor CD155, which is widely expressed on both the malignant cells of most solid tumors and key antigen presenting cells within the tumor microenvironment. PVSRIPO targets tumors using three key mechanisms: 1) engagement and activation of antigen presenting cells (APCs), leading to T cell priming and sustained, systemic anticancer immunity; 2) direct tumor cell killing and antigen release; and 3) amplification of the immune response via recall of poliovirus vaccine-specific T cells. PVSRIPO has been granted Breakthrough Therapy and Orphan Drug Designation status by the U.S. Food and Drug Administration in recurrent glioblastoma, and Fast Track and Orphan Drug Designation status in refractory melanoma.

About Istari Oncology

Istari Oncology, Inc., headquartered in Research Triangle Park, North Carolina, is a privately held clinical-stage biotechnology company developing novel immunotherapies for the treatment of glioblastoma and a wide variety of solid tumors. Istari has licensed a broad range of patents and patent applications, and has access to additional intellectual property to continue clinical and commercial development of these technologies. The company’s primary asset currently in clinical development is PVSRIPO. For more information, please visit:

1 Bladder Cancer Advocacy Network (BCAN). Accessed August 8, 2021.

2 The American Cancer Society. Key Statistics for Bladder Cancer. Accessed August 8, 2021.

SOURCE: Istari Oncology