PGT, an experimental chemotherapy developed by OncBioMune, inhibited the growth of ovarian cancer cells resistant to multiple chemotherapeutic agents. These preliminary results suggest that the therapy could potentially be used to treat tumors that do not respond to standard chemotherapy.

PGT is a combination of paclitaxel, gallium, and transferrin aimed at increasing the efficacy of the chemotherapy and lessening its toxicity to non-cancer cells.

Transferrin is the protein that transports iron in the plasma and specifically delivers it to cells that have the CD71 receptor on their surface. Cancer cells have up to 1,000 times more CD71 receptor than other cells in the body because they need large amounts of iron to divide constantly and rapidly.

PGT specifically delivers paclitaxel — a commonly used chemotherapeutic agent — and gallium — a heavy metal with anti-cancer activity — to cancer cells by combining them with transferrin. This way, the treatment is expected to achieve results similar to other chemotherapies at much lower concentrations and without interfering with non-cancer cells.

Researchers assessed the effects of PGT and paclitaxel monotherapy on a breast cancer cell line that responds to chemotherapy and an ovarian cancer cell line that is resistant to most chemotherapeutic agents to test whether PGT could overcome the resistance.

Both therapies inhibited the growth of the susceptible cell line at similar concentrations. However, PGT inhibited the growth of the resistant cell lines at a concentration 6,797 times lower than that of paclitaxel. Furthermore, the concentration at which the resistant cells responded to PGT was similar to that approved for other chemotherapies currently on the market.

“This is only one experimental model, but it does suggest that PGT has the potential to show activity in cancer cells that are resistant to standard chemotherapies that are used widely in patients today,” Brian Barnett, OncBioMune’s CEO, said in a press release.

“This experiment utilizes a well-characterized ovarian cancer cell line that is multi-drug resistant. In the near future, we plan to perform tests on other models as we are hopeful that this therapy may show broad activity in multiple cancer types with the ultimate goal of developing PGT for patients with refractory cancers, an area of high unmet medical need,” he said.