LTX-315, an oncolytic peptide, to convert immunogenically ‘cold’ tumors to ‘hot’ in patients with advanced or metastatic tumours: Results from an ongoing phase I study.

Summary

Intratumoral LTX-315 disintegrates cytoplasmic organelles with release of tumor antigens in preclinical models accompanied by increase in tumor-infiltrating lymphocytes (TILs). LTX-315 induced complete regression in several rodent models, with systemic immune responses. LTX-315 is strongly synergistic preclinically with immune checkpoint inhibitors (ICI). We are conducting a phase 1 trial to evaluate LTX-315 in combination therapy. Patients with advanced metastatic solid tumours received injections of LTX-315 into a single accessible tumour over 6 weeks. Additional injections could be administered thereafter every 2 weeks. Biopsies of injected lesions were taken at baseline, and on treatment. Stable disease (median duration 14 weeks) occurred in 50% of patients as best response (melanoma (4), sarcoma (3), breast (1)). This phase 1 study demonstrates that intratumoural LTX-315 has a manageable safety profile and induces increases in TILs in pre-treated patients. Partial and complete regression was seen in some injected tumours. Evaluation of LTX-315 in combination with ICIs in breast and melanoma is ongoing.