Phosplatin Therapeutics Announces First Patient Dosed in Phase 2 Clinical Trial of PT-112 for Thymoma and Thymic Carcinoma in Collaboration with National Cancer Institute

NEW YORK, April 13, 2022 /PRNewswire/ -- Phosplatin Therapeutics Inc., a clinical stage pharmaceutical company focused on oncology therapeutics, today announced the first patient has been treated in a Phase 2 clinical trial of the company's lead therapeutic candidate, PT-112, in patients with recurrent thymic epithelial tumors (TETs), specifically thymoma and thymic carcinoma. The trial is being conducted under formal collaboration with the National Cancer Institute (NCI), part of the National Institutes of Health (see NCT05104736).

The Phase 2 trial is designed to further assess the safety and efficacy of PT-112 in patients with thymoma and thymic carcinoma, and to use correlative studies to explore molecular profiles, examine parameters of immune activation and analyze immune cell infiltration in response to PT-112 treatment, as the candidate is known to promote immunogenic cell death (ICD). ICD is an immunostimulatory form of cancer cell death in the tumor microenvironment, and PT-112's highly potent induction of ICD has been validated in relevant cancer models.

Phosplatin is providing NCI with PT-112 drug supply and support for correlative research, and NCI is overseeing enrollment and dosing of the study's intended 53 patients.  To be eligible for the study, patients must have uncommon tumors of the thymus (TETs) returned or progressed after treatment with at least one platinum-containing chemotherapy, or have refused standard treatment. The primary endpoint is overall response rate (ORR) per RECIST 1.1 criteria.  The secondary endpoint measures include safety, duration of response, progression free survival, overall survival and ORR based on ITMIG-modified RECIST criteria (as established by the International Thymic Malignancy Interest Group).

"As an immunomodulatory treatment, PT-112 has performed well in early phase trials for TETs and warrants additional Phase 2 testing. Given the significant unmet need for patients with recurrent TETs, with no established immunotherapy option and no approved drug, it is important that we continue to study potential therapies," said Arun Rajan, MD, Senior Clinician in the Thoracic and GI Malignancies Branch at the NCI.

"In our Phase 1 trial of PT-112, we reported favorable safety data and observed a durable clinical response in a patient with advanced metastatic thymoma, which had the signature of potential immune involvement to the response," said Robert Fallon, Phosplatin President and Chief Executive Officer. "We are excited to work with Dr. Rajan and his outstanding team at the NCI to further study the potential of PT-112 to provide significant benefit to patients with these cancers." 

Phosplatin holds an FDA Orphan Drug Designation for PT-112 in thymoma and thymic carcinoma. TETs, including thymomas and thymic carcinomas, are uncommon tumors of the thymus for which there is no FDA-approved drug. The five-year survival rate for patients with thymoma or thymic carcinoma is 55%.  In cases of relapse following surgical intervention, TETs have the potential to metastasize and there are limited options for treatment.

PT-112 is the first small-molecule conjugate of pyrophosphate in oncology, and possesses a unique pleiotropic mechanism of action that promotes immunogenic cell death (ICD), through the release of damage associated molecular patterns (DAMPs) that bind to dendritic cells and lead to downstream immune effector cell recruitment in the tumor microenvironment. PT-112 represents a highly potent inducer of this immunological form of cancer cell death. Further, PT-112 harbors a property known as osteotropism, or the propensity of the drug to reach its highest concentrations in certain areas of the bone, making it a candidate for treatment of patients with cancers that originate in, or metastasize to, the bone. The first in-human study of PT-112 demonstrated an attractive safety profile and evidence of long-lasting responses among heavily pre-treated patients and won "Best Poster" within the Developmental Therapeutics category at the ESMO 2018 Annual Congress. The combination Phase 1b dose escalation study of PT-112 with PD-L1 checkpoint inhibitor avelumab in solid tumors was reported in an oral presentation at the ESMO 2020 Virtual Congress. The Phase 1 study in patients with relapsed or refractory multiple myeloma presented at ASH is the third completed Phase 1 study of PT-112. Monotherapy Phase 2 development is ongoing in mCRPC, and now includes the Phase 2 proof of concept study in thymic epithelial tumors under the company's formal collaboration with the NCI. The PD-L1 combination Phase 2a study is ongoing in a dose confirmation cohort of non-small cell lung cancer (NSCLC) patients.

Phosplatin Therapeutics Inc. is a privately held, clinical stage pharmaceutical company that holds exclusive global license to phosphaplatins, a family of small molecules rationally designed to circumvent the mechanisms of drug resistance and toxicity commonly associated with chemotherapeutic regimens. The company's lead candidate, PT-112, is a novel chemical entity under clinical development that exhibits a unique combination of properties, including immunogenic cell death and osteotropism. Clinical data generated to date across three Phase 1 studies have demonstrated single-agent anti-cancer activity and an attractive tolerability profile, and three Phase 2 studies of PT-112 are underway. The company's research and development work has been funded by private investors and family investment offices in the United States, Europe and Asia, along with a sub-license agreement for the development, commercialization and use of PT-112 in Greater China. The company also sponsors the ongoing clinical study of PT-112 in combination with the PD-L1 inhibitor avelumab under a collaboration agreement with Pfizer and Merck KGaA, Darmstadt, Germany (operating as EMD Serono in the US and Canada), and has an active collaborative research and development agreement (CRADA) with the NCI to conduct a Phase 2 trial utilizing PT-112 in thymic epithelial tumors.

CONTACTS:

Phosplatin Therapeutics 
Taylor B. Young
Senior Director, Strategic Development
Tel: +1 646 380 2441
Email: [email protected]

ICR Westwicke
Investors:
Stephanie Carrington
Tel: +1 646 277 1282
Email: [email protected]

Media: 
Mark Corbae
Tel: +1 203 682 8288
Email: [email protected]

SOURCE Phosplatin Therapeutics