Vectibix and best supportive care improves OS in mCRC

Amgen has announced results from a Phase 3 study of Vectibix (panitumumab) and best supportive care (BSC) compared to BSC alone in patients with chemorefractory wild-type KRAS (exon 2) metastatic colorectal cancer (mCRC). 

The study met its primary endpoint, demonstrating a statistically significant improvement in overall survival (OS). This is the first Phase 3 Vectibix study to include an analysis of efficacy of Vectibix by wild-type KRAS (exon 2) and in wild-type RAS tumour mutation status in its primary analysis, providing important information about OS in these populations.

The study showed that patients with wild-type KRAS (exon 2) mCRC treated with Vectibix and BSC achieved a median OS of 10 months compared to 7.4 months for patients treated with BSC alone. Data from a key secondary endpoint showed that patients with wild-type RAS (absence of mutations in exons 2, 3 and 4 of KRAS and NRAS) mCRC treated with Vectibix and BSC achieved a median OS of 10 months compared to 6.9 months for patients treated with BSC alone. Patients with mutant RAS mCRC did not benefit from Vectibix treatment. The safety profile was comparable to the known safety profile of Vectibix when administered as a single agent, with skin, nail, gastrointestinal and electrolyte disorders being the most frequently reported adverse events.

Data supports expanding biomarker screening to include wild-type RAS

Commenting on the results, Sean E. Harper, M.D., executive vice president of Research and Development at Amgen, said: “Amgen has played a significant role in the advancement of personalised medicine, applying cutting-edge science and technology in our efforts to target therapies to the patients who are most likely to benefit. Amgen is committed to understanding cancer biology through studies like this. As well as providing additional insights into the way Vectibix works in mCRC, these data support expanding biomarker screening to include wild-type RAS.”

Key secondary endpoints included progression-free survival (PFS) in patients with wild-type KRAS mCRC, as well as OS and PFS in patients with wild-type RAS (absence of mutations in exons 2, 3 and 4 of KRAS and NRAS) mCRC, objective response rate (ORR) and safety in both wild-type KRAS (exon 2) and wild-typeRAS groups.

Treatment with Vectibix combined with BSC in patients with wild-type KRAS resulted in median PFS of 3.6 months versus 1.7 months with BSC alone. In patients with wild-type RAS, the Vectibix combination resulted in median PFS of 5.2 months versus 1.7 months with BSC alone.

For patients with wild-type KRAS, ORRs were 27.0% with Vectibix versus 1.6% with BSC. For patients with wild-type RAS, ORRs were 31.0% with Vectibix versus 2.3% for BSC.