The news is a devastating blow to the two pharmaceutical companies, which has not only delayed the filing of the drug for market approval but has seen both companies share prices hit hard.
In the local analysis by the trial doctors, the drug appeared to extend the time it takes cancer to worsen when compared to chemotherapy alone in some instances. But a central review of the study data failed to prove this result was "statistically significant" and was unable to exclude the possibility that the positive effect was accidental.
The two firms said they would delay submitting PTK/ZK for regulatory approval by a year to early 2007 following a study on the drug taken in combination with standard chemotherapy.
David Epstein, CEO of specialty medicines and president of Novartis Oncology responded to the disappointment saying: "The recommendation by the independent monitoring board to continue the Phase III program, and the investigator assessment of progression encourage us to further explore the potential benefit of PTK/ZK in patients suffering from metastatic colorectal cancer and other cancers."
Both companies decision to press on with further trials into PTK/ZK's potential demonstrates the confidence it has for this unique investigational compound and its novel mechanism of action.
PTK/ZK is an investigational oral multi-VEGF receptor tyrosine kinase inhibitor, which blocks tumour angiogenesis and lymphangiogenesis by inhibiting all known VEGF receptors. Targeting all the VEGF receptors rather than a single VEGF type may provide a new approach for inhibiting tumour growth and spread.
The setback is good news for Switzerland-based Roche, who now have prime market position with Avastin, a rival treatment launched in the United States a year ago and in Europe at the beginning of 2005. Roche will also have more time to test Avastin in combination with the same, newer chemotherapy regimen, Folfox-4, that Novartis and Schering are testing their drug against.
The drug is one of a new generation of cancer drugs, the so-called targeted drugs. These drugs focus on cancerous cells only, while older cancer treatments kill sick and healthy cells alike, which often leads to severe side effects.