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Our Viral immunotherapy and Antibody-Toxin Conjugate Pipeline

Expanding Potentially Transformative Therapy Options for the Treatment of Recurrent Glioblastoma Multiforme (rGBM) and a Variety of Solid Tumors.


Tumor Type


Phase 1

Phase 2

Phase 3

Viral Immunotherapy


PVSRIPO monotherapy


PVSRIPO + pembrolizumab


PVSRIPO + anti-PD-1/L1

Other Solid Tumors

PVSRIPO + anti-PD-1/L1

Antibody-Toxin Conjugate




D2C7 + atezolizumab

Istari is progressing clinical research on multiple fronts with the powerful, versatile PVSRIPO technology. A Phase 2 clinical study in recurrent glioblastoma multiforme (rGBM) is now fully enrolled. The LUMINOS-101 Phase 2 clinical trial assessing PVSRIPO in combination with pembrolizumab in patients with rGBM enrolled its first patient in November 2020.

The LUMINOS-102 Phase 2 study investigating PVSRIPO alone or in combination with a PD-1 inhibitor in patients with treatment-refractory melanoma received IND clearance in November 2020 and will begin enrolling patients soon. Data from the Phase 1 study of PVSRIPO in patients with unresectable treatment refractory melanoma was presented at The Society for Immunotherapy of Cancer (SITC) 35th Anniversary Annual Meeting. For more details on the data that was presented click on the poster below.

Beasley SITC 2020 Poster showing phase I trial of Intratumoral PVSRIPO

Clinical studies in other solid tumor types are planned for 2021.

Istari’s Antibody Toxin Conjugate (ATC), D2C7, is under evaluation in a dose escalation Phase 1 study. We also have ATCs for additional tumors in pre-clinical development. Using different cytotoxic agents and linkers may lead to additional pipeline therapeutics for Istari Oncology. A wide variety of tumor types can be targeted by ATCs.

Learn more about our ongoing clinical studies with PVSRIPO and ATCs.

Therapeutic Areas

Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most aggressive and most common malignant primary brain tumor, making up 54% of all gliomas and 16% of all primary brain tumors. Each year, more than 13,000 patients diagnosed with GBM in the United States and virtually all patients experience recurrence.

Current treatments are mainly palliative and involve a combination of surgery, radiology therapy, temozolomide and tumor treating fields (TTFs). These therapies elucidate only a modest enhancement in survival with newly diagnosed glioblastoma and virtually no benefit in recurrent tumors. GBM remains an incurable tumor with a median survival of only 16-20 months after diagnosis and treatment with current options.

These outcomes highlight the need for a new therapy to change the course of care for patients with GBM. Given the need for individualized patient treatments, we believe that there is ample opportunity to improve patient outcomes with targeted therapies. As such, Istari is pursuing recurrent GBM as a target indication with its PVSRIPO and ATC technologies.


There are estimated to be over 12,000 new and recurrent cases of advanced, unresectable melanoma diagnosed in the US each year, and around 7,000 deaths. While checkpoint inhibitors have dramatically improved the outlook for advanced melanoma patients today, most patients treated with these immunotherapies are either primary non-responders or eventually develop immuno-refractory progressive disease and require additional therapy.

Istari is investigating PVSRIPO as a potential new option alone or in combination with anti-PD-1/L1s for checkpoint-refractory advanced melanoma.

Other Potential Indications

The target for PVSRIPO, CD155 (the poliovirus receptor) is expressed in virtually all solid cancers. Therefore, many, solid tumor types may represent targets for PVSRIPO. We plan to initiate a basket trial in new solid tumor targets in 2021.

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