Rigosertib is an inhibitor of two important cellular signaling pathways, PI3K and PLK, both of which are frequently over-active in cancer cells. PI3K signaling promotes the growth and survival of cells under stressful conditions, such as under low oxygen levels that are often found in tumors. If the PI3K pathway is over-active, apoptosis of cancer cells is diminished, leading to excessive cellular growth. By inhibiting the PI3K pathway, rigosertib promotes tumor cell apoptosis. Rigosertib also influences signals along the PI3K pathway, such as those leading to the production of cyclin D1.
The PLK pathway plays a critical role in maintaining proper organization and sorting of chromosomes during cell division. Too much PLK activity in cancer cells results in uncontrolled proliferation. By modulating PLK pathway activity in cancer cells, rigosertib inhibits cellular division, leading to chromosome disorganization and death in these cells.
Due to this dual effect on tumor cell survival and division pathways, we believe that rigosertib has potential to treat a variety of cancer types, including hematological diseases and solid tumors. Ongoing clinical trials are evaluating the activity of rigosertib in:
- Myelodysplastic Syndromes (MDS)
- Head & Neck Cancer
- Other hematological diseases and solid tumors
Ongoing and completed Phase 1, Phase 2 and Phase 3 clinical trials have generated data in over 850 patients with advanced, heavily pre-treated solid tumors and hematological diseases and have demonstrated a desirable safety profile for rigosertib.