Amphinex (fimaporfin)

During the first 20 days post-ATRA+PDT, we obtained significant anti-tumour responses in HT-29 xenografts, including complete responses in 2/5 mice. In conclusion, ATRA+PDT represent a novel combination therapy for solid tumours that should be further tested in immunocompetent preclinical models.

Using fluorescence microscopy, we reveal that the anti-PD-L1 antibody binds to PD-L1 on the surface of the MDA-MD-231 cells and overnight accumulates in late endosomes and lysosomes where it co-localizes with the PCI photosensitizer fimaporfin (TPCS)...In conclusion, our work provides an in vitro proof-of-concept of PCI-enhanced targeting and eradication of PD-L1 positive immunosuppressive cells. This light-controlled combinatorial strategy has a potential to advance cancer immunotherapy and should be explored in preclinical studies.

By using the ALDEFLUOR assay, CD133 + human colon cancer cells HT-29, were FACSorted into three populations: ALDH, ALDH and unsorted (bulk) and treated with chemo-, radio- or photodynamic therapy (PDT) using the clinical relevant photosensitizer disulfonated tetraphenyl chlorin (TPCS/fimaporfin)...Likewise, both 5-FU and oxaliplatin chemotherapy efficacy was not reduced in ALDH as compared to ALDH cancer cells...This study demonstrates that the cytotoxic response to PDT (using TPCS2a as photosensitizer) is independent of ALDH activity in HT-29 cancer cells. Our results further strengthen the use of TPCS2a to target CSCs.