Panitumumab shows promise in metastatic colorectal cancer

26 Jan 2016

Amgen has announced the presentation of detailed results of a Phase 3 study with panitumumab (marketed as Vectibix) and best supportive care compared to best supportive care alone in metastatic colorectal cancer (mCRC).

The study met its primary endpoint, demonstrating a statistically significant improvement in overall survival in patients with chemo-refractory wild type KRAS (exon 2) mCRC (377 total).

This is the first Phase 3 panitumumab study to include an analysis of efficacy of panitumumab by wild-type KRAS (exon 2) and in wild-type RAS tumor mutation status in its primary analysis, providing important information about overall survival in these populations.

Colorectal cancer: the third most common cancer worldwide

Colorectal cancer is the third most common cancer worldwide, with approximately 1.2 million cases occurring globally each year. Approximately 20% of colon cancers are diagnosed at the metastatic stage, when the disease has already spread to distant organs, a diagnosis associated with only a 12% five-year survival rate.

Using molecular approaches to identify unique genetic signatures in mCRC has the potential to help improve treatment outcomes. Of the few biomarkers in colorectal cancer, RAS genes (KRAS, NRAS) have a validated impact on treatment outcomes.

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Clinical results and adverse events

The study showed that:

  • Patients with wild-type KRAS (exon 2) mCRC treated with panitumumab and best supportive care achieved a median overall survival of 10 months compared to 7.4 months for patients treated with best supportive care 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 best supportive care achieved a median overall survival of 10 months compared to 6.9 months for patients treated with best supportive care alone.
  • Patients with mutant RAS mCRC did not benefit from panitumumab.

The safety profile was comparable to the known safety profile of panitumumab when administered as a single agent, with skin, nail, gastrointestinal and electrolyte disorders being the most frequently reported adverse events.

“As well as providing additional insights into the way Vectibix (panitumumab) works in mCRC, these data support expanding biomarker screening to include wild-type RAS,” said Sean E. Harper, M.D., executive vice president of Research and Development at Amgen.

Source: eCancer News
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