The molecule was developed by a team from the Department of Chemistry at the Faculty of Science and Technology of the University of Coimbra (FCTUC), in collaboration with the company Luzitin SA.

According to the institution, the development of effective drugs against solid tumours faces two major challenges: the selective accumulation of the drug in the tumour and its ability to infiltrate and reach all tumour cells.

The dominant approach has been to develop increasingly larger molecules and more complex nanoparticles, which, despite increasing selectivity, compromise penetration into dense and rigid tumours.

The Coimbra team, bucking the trend, opted for the innovative strategy of identifying the smallest molecular structure with ideal pharmacological properties for photodynamic therapy.

This resulted in the synthesis of the LUZ51 molecule, the smallest known photosensitiser that absorbs infrared light.

According to Luís Arnaut, professor at FCTUC, Photodynamic Therapy “is based on the activation of a photosensitiser through red or infrared light” and, in the presence of oxygen, “this activation triggers a cascade of chemical reactions that lead to the death of tumour cells”.

“One of the great advantages of this therapy is its high selectivity: the drug is practically harmless without light, allowing the tumour to be destroyed only in the illuminated area,” explained the researcher from the Coimbra Chemistry Centre, quoted in a press release sent to the Lusa agency.

Studies have shown that LUZ51 accumulates 13 times more in tumours than in adjacent tissues, is rapidly internalised by tumour cells and induces their death when activated by infrared light.

In animal models, Photodynamic Therapy with LUZ51 has cured mice with aggressive and relatively large tumours, preserving surrounding healthy tissue and minimising adverse effects.

“One of the most remarkable results was observed in the treatment of the human analogue of triple-negative breast cancer. Even when the primary tumour already showed signs of metastasis to the lungs, local treatment with LUZ51 led to a significant reduction and, in some cases, elimination of lung metastases,” revealed the scientist.

“These data suggest that Photodynamic Therapy with LUZ51 may activate the host’s immune system, promoting an antitumour response beyond the directly treated area,” he added.

Despite the enormous potential demonstrated, the researchers stressed that LUZ51 will still need to be evaluated in clinical trials before it can be used in cancer patients, a process that could take around five years.

Nevertheless, the discovery opens up new prospects for more selective, effective treatments with less impact on healthy tissue.

The LUZ51 molecule has been patented by the University of Coimbra and Luzitin SA, and the results of the in vivo studies have been published in the scientific journal Angewandte Chemie International Edition.