The meeting dealt with the preliminary results of a Phase 1 trial (NCT01837095) showing that balixafortide is the first CXCR4 inhibitor to display signs of effectiveness against solid tumors.
Balixafortide is a selective antagonist of CXCR4, a receptor that regulates cancer cell migration and immune cells’ ability to hone in on cancer cells.
CXCR4 also influences tumor growth, survival, blood vessel formation, and metastasis. High levels of CXCR4 have been observed in nearly all tumor types, and its expression is thought to correlate with aggressive metastatic behavior.
The meeting with U.S. Food and Drug Administration officials opened the door to Polyphor conducting a single pivotal trial of balixafortide for approval in the United States. The trial would involve a combination of balixafortide and Halaven (eribulin) in patients who had received at least two lines of chemotherapy.
A single pivotal trial could allow balixafortide to be available in the U.S. by 2021 — or even 2020, in case of accelerated approval. The FDA would have to agree that interim results on patients’ overall response rate to the combo and duration of response were acceptable.
In the Phase 1 trial, balixafortide plus Halaven led to at least a stable disease in 63 percent of patients. In 38%, the treatment shrank the tumors. The safety and tolerability of the combination were similar to that seen in either agent alone, the company reported.
“This development significantly strengthens Polyphor’s late-stage clinical pipeline,” Giacomo Di Nepi, chief executive officer of Polyphor, said in a press release. “We now have two products entering the final stage of clinical development ,and with a clear path to market.”
“Our highly constructive discussion with the FDA has resulted in specific next steps towards a pivotal trial to potentially support registration for balixafortide,” he said. “We are grateful to the agency for its guidance and look forward to fully defining a development pathway to rapidly bring this new potential treatment option to women suffering from a disease that today still has poor prognosis and outcomes.”
“There is an ongoing need for novel treatments for patients with late-stage HER2-negative breast cancers,” said Javier Cortes, head of the breast cancer program at Ramon y Cajal University Hospital in Madrid. “The preliminary anti-tumor activity and tolerability we have seen with balixafortide in combination with eribulin has been very encouraging and has potential to provide a new therapeutic option in these patients.”