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CytomX raises hopes for a win

It took nothing more than a promise of data to send CytomX shares surging yesterday. The stock more than tripled when the company said initial phase 1a results on an Amgen-partnered asset, CX-904, would come alongside earnings next week. A series of pipeline setbacks means the company desperately needs a win. CytomX claims that its “probody” masking technology can help avoid off-target toxicity, unlocking the potential of T-cell engagement. As such, any hint of dose-limiting toxicities in CX-904’s first clinical update would be a big disappointment. The anti-EGFR project is undergoing dose escalation in a phase 1a trial in patients with advanced EGFR-expressing solid tumours. Amgen is to decide this year whether to expand the trial into phase 1b, and a strong showing next week will raise hopes for such an outcome. Investors’ enthusiastic response to early data from Janux earlier this year demonstrates the value seen in a successful masking technology. CX-904 is likely to be held up against that company’s EGFR asset, JANX008, on which early phase 1 data are available. One confirmed partial response in lung cancer and hints of efficacy in colon cancer are a bar of sorts for CytomX to beat. Banishing the spectre of failed past projects will take longer. 


JANX008: Early data from a phase 1 trial in advanced tumours