Progression-Free Survival Endpoint Not Reached in Abituzumab Study

the Cancer Therapy Advisor take:

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.