Phosplatin Therapeutics has dosed the first subject in a Phase II clinical trial of its lead therapeutic candidate, PT-112, to treat specific individuals with recurrent thymic epithelial tumours (TETs), thymoma and thymic carcinoma

A small-molecule conjugate of pyrophosphate, PT-112 possesses a distinctive pleiotropic mechanism of action that induces immunogenic cell death (ICD).

PT-112’s ability to induce ICD has been established in relevant cancer models.

In addition, it possesses osteotropism property or the propensity of the drug to reach its maximum concentrations in specific parts of the bone, making it suitable to treat patients with tumours that originate in, or metastasize to, the bone. 

Being carried out in partnership with the US National Institutes of Health unit National Cancer Institute (NCI), the trial will evaluate the safety and efficacy of PT-112 in thymoma and thymic carcinoma patients.

The trial will also study molecular profiles, monitor immune activation parameters and assess immune cell infiltration following treatment with PT-112.

Patients with uncommon tumours of the thymus (TETs) that have returned or advanced following treatment with a minimum of one platinum-containing chemotherapy or were refused standard therapy, will be part of the trial. 

Overall response rate (ORR) according to RECIST 1.1 criteria is the primary endpoint of the trial. 

Safety, progression-free survival, overall survival, duration of response and ORR based on ITMIG-modified RECIST criteria will be included as the secondary endpoint measures.

The company is offering PT-112 drug supply to NCI and will back the correlative study while NCI is handling the enrolment and dosing of the 53 trial subjects. 

Phosplatin president and CEO Robert Fallon said: “In our Phase I trial of PT-112, we reported favourable 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.”