Biocytogen Pharmaceuticals and Tracon Pharmaceuticals have obtained clearance for the Investigational New Drug (IND) application from the US Food and Drug Administration (FDA) to begin the Phase I/II clinical trial of YH001 plus envafolimab and doxorubicin to treat sarcoma patients.

The trial will analyse the safety and efficacy of YH001 plus envafolimab in subjects with alveolar soft part sarcoma and chondrosarcoma, which are rare subtypes of sarcoma.

It will also evaluate the safety and efficacy of YH001 plus envafolimab and doxorubicin for leiomyosarcoma and dedifferentiated liposarcoma, the common subtypes of sarcoma.

Patients who have not previously received any treatment will be enrolled in the trial.

An IgG1 antibody, YH001 acts on CTLA-4.

The Biocytogen-invented antibody was licensed by Tracon. 

YH001 showed enhanced T cell activation and superior tumour growth inhibition activity versus ipilimumab in preclinical research as a monotherapy, as well as in combination with a PD-(L)1 antibody in human transgenic mouse tumour models. 

In such models, YH001 monotherapy led to the depletion of regulatory T cells and boosted CD8+ T cells in tumour tissue. 

Tracon CEO Charles Theuer said: “We are pleased to receive approval from the FDA to initiate our triplet combination therapy study in sarcoma, which includes our potentially best-in-class CTLA-4 antibody YH001 and the only subcutaneous checkpoint inhibitor approved anywhere in the world, envafolimab. 

“We look forward to enrolling patients in this study and giving patients additional options for their sarcoma treatment.”

In a Phase I trial in China, YH001 was dosed as a monotherapy and along with toripalimab, a PD-1 antibody, in a Phase I trial in Australia.

In February this year, Tracon initiated the Phase II trial of TRC102 (methoxyamine) plus chemoradiation in stage III non-squamous, non-small cell lung cancer patients.