Genmab said on October 25, 2026, that an updated Phase 2 petosemtamab trial showed tumor responses in patients with metastatic colorectal cancer receiving the investigational antibody alongside chemotherapy. Two Phase 3 colorectal cancer trials are enrolling patients.
Key Takeaways
- The reported response rates included both confirmed and unconfirmed responses.
- The Phase 2 study was single-arm, so it did not establish how the combination compares with chemotherapy alone.
- Genmab has scheduled an investor update for October 28, 2026.
Petosemtamab trial results
As of the May 15, 2026, data cutoff, 79 patients had received petosemtamab with either FOLFOX or FOLFIRI chemotherapy: 45 as first-line treatment and 34 as second-line treatment. Among patients evaluable for efficacy, the objective response rate was 75% in the first-line group and 67% in the second-line group.
The response rates measure the proportion of evaluable patients whose tumors responded to treatment. Most responses previously reported as unconfirmed were subsequently confirmed, Genmab said. Median follow-up was 5.9 months for first-line patients and 7.1 months for second-line patients.
The ongoing, open-label study enrolled patients with RAS/BRAF wild-type metastatic colorectal cancer who had not previously received an EGFR-targeted therapy. Its single-arm design means the results do not isolate petosemtamab's contribution to the combination.
| Item | Details |
|---|---|
| First-line patients | 75% objective response rate; median follow-up of 5.9 months. |
| Second-line patients | 67% objective response rate; median follow-up of 7.1 months. |
| First-line patients with left-sided tumors | 81% objective response rate. |
Safety and later-stage studies
Adverse events related to petosemtamab led to its discontinuation in two of 42 patients receiving it with mFOLFOX6 and one of 37 receiving it with FOLFIRI. No treatment-emergent adverse events leading to death were reported.
Infusion-related reactions occurred in 48% of patients receiving petosemtamab plus FOLFOX and 43% receiving it plus FOLFIRI. Grade 3 infusion reactions occurred in three and one patients in those respective groups.
Genmab's two enrolling Phase 3 colorectal cancer studies cover first-line treatment for patients with left-sided tumors and second-line treatment for patients with recurrent, unresectable or metastatic disease. Both studies focus on RAS/BRAF wild-type cancer.
Next milestone
Genmab is scheduled to host an investor update on October 28 at 5 p.m. Central European Time.
Read More News
Disclaimer
This FinanceVelix article provides general information, not personalized financial, investment, legal, or tax advice. Market prices, interest rates and economic conditions can change; investments carry a risk of loss. Facts reflect the material available when published and may change. Check important information independently and consult a qualified professional when needed. Mentioning an asset, company, or service is not an endorsement.
Comments
Be respectful. No spam, impersonation or private credentials. Ordinary posts and comments appear immediately; suspicious links are held for review.
Please wait…