Cancer failure prompts Polyphor to give up entirely

Polyphor’s decision to can its CXCR4 antagonist balixafortide following the dismal results of the Fortress trial in breast cancer last month hands a clear win to Biolinerx. The Israeli company now has the most advanced CXCR4 antagonist in development for cancer, with several phase 2 trials ongoing in pancreatic cancer and various blood malignancies. The failure of Polyphor’s Fortress study was indisputable, with balixafortide plus eribulin showing no improvement in objective response rate or clinical benefit over eribulin alone as a third line and later treatment for Her2-negative breast cancer. Giving up in cancer is sensible; the mystery is why Polyphor is not pursuing stem cell mobilisation. Balixafortide is mechanistically identical to Sanofi’s Mozobil, approved in 2010 for stem cell mobilisation, and there is no reason why balixafortide would not work here too. Perhaps competition is the problem – Mozobil comes off patent in 2023, a generic form is already poised to enter the market, and Biolinerx’s phase 3 study of motixafortide was toplined as a hit two months ago. Whatever its reason, Polyphor is now in the grip of a restructuring. 

Selected antagonists of CXCR4
Project Company Notes
Mozobil Sanofi (ex Genzyme) Sold as adjunct to stem cell mobilisation
Plerixafor Zydus Cadila Generic of Mozobil; tentatively approved for stem cell mobilisation
Biolinerx Ph3 for stem cell mobilisation hit in May 2021; ph2 for pancreatic and blood cancers; ph1 for various blood disorders and Covid-19
Mavorixafor X4 Pharmaceuticals
(ex Sanofi)
Ph3 for Whim syndrome; ph1 for neutropenia and Waldenstrom's macroglobulinemia
MGTA-145 Magenta Therapeutics Ph2 for stem cell mobilisation and blood cancers; ph1 for renal disease
Balixafortide Polyphor Discontinued after ph3 failure in breast cancer; development in stem cell mobilisation also ceased (ph2 completed 2016)
Source: Evaluate Pharma &

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