According to a new study published in the Annals of Oncology, the randomized phase 1/2 POSEIDON trial investigating the use of abituzumab combined with cetuximab and irinotecan for the treatment of patients with KRAS wild-type metastatic colorectal cancer did not meet its primary progression-free survival endpoint.
For the study, researchers sought to investigate abituzumab, a humanized monoclonal antibody that targets intregrins involved in tumor progression and metastasis. Patients with KRAS wild-type metastatic colorectal cancer who had progressed after oxaliplatin-containing therapy were randomly assigned to receive abituzumab 500mg every 2 weeks with cetuximab and irinotecan (arm A), abituzumab 1000mg every 2 weeks with cetuximab and irinotecan (arm B), or cetuximab and irinotecan alone (arm C).
The phase 1 portion of the study demonstrated abituzumab was safe at doses up to 1000mg. Results showed similar progression-free survival rates among all three arms in the phase 2 part.
The hazard ratio of arm A versus arm C was 1.13 (95% CI 0.78 - 1.64) and the hazard ratio of arm B compared with arm C was 1.11 (95% CI 0.77 - 1.61). Results showed similar response rates among all three arms, but researchers note that there was a trend toward improved overall survival in patients treated with abituzumab.
This trial was designed to assess the tolerability of different doses of abituzumab in combination with cetuximab and irinotecan (phase I) and explore the efficacy and tolerability of the combination versus that of cetuximab and irinotecan in patients with metastatic CRC (mCRC) (phase II part).