PT-112 Treatment for Thymoma and Thymic Carcinoma Starts in a Phase 2 Study

The first patient has been dosed with PT-112 in a phase 2 clinical trial (NCT05104736) testing patients with recurrent thymic epithelial tumors (TETs), specifically patients with thymoma and thymic carcinoma. The National Cancer Institute (NCI) is collaborating with the study investigators to oversee enrollment and dosing in this trial.¹

This phase 2 trial will further assess the safety and efficacy of PT-112 in patients with thymoma and thymic carcinoma and will use correlative studies to explore molecular profiles, examine parameters of immune activation and analyze immune cell infiltration in response to PT-112 treatment. PT-112 has shown to promote immunogenic cell death (ICD). PT-112's highly potent induction of ICD has been validated in relevant cancer models.

Patients will receive 360 mg/m² of PT-112 by infusion through a catheter on days 1, 8, and 15 of 28-day cycles. On treatment days, patients will have physical exams and blood and urine tests. Patients will have scans every 8 weeks and may choose to have tumor biopsies on day 1 of cycles 1 and 3. Biopsies may be guided by an ultrasound or CT scan. Patients will continue treatment until they experience worsening disease or intolerable adverse events.² Participants will have follow-up visits 2 weeks and 4 weeks after they stop therapy. The study team will check on participants every 3 months.

Investigators intend to enroll 53 patients. Eligible patients must have uncommon TETs returned or progressed after treatment, with at least one platinum-containing chemotherapy or have refused standard treatment. The primary end point is overall response rate (ORR) per RECIST 1.1 criteria.The secondary end points are safety, duration of response, progression free survival, overall survival and ORR based on ITMIG-modified RECIST criteria which was 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," commented Arun Rajan, MD, senior clinician in the thoracic and gastrointestinal malignancies branch at the NCI.¹

"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."

The FDA granted an orphan drug designation for PT-112 in thymoma and thymic carcinoma in 2018.

_References

_{1. 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. Press release. PR Newswire; April 13, 2022. Accessed April 13, 2022. https://bit.ly/3KHwMRC}

_{2. PT-112 in subjects with thymoma and thymic carcinoma. ClinicalTrials.gov. Updated April 12, 2022. Accessed April 13, 2022. https://bit.ly/3M8RKcD}