Pumitamig for previously untreated, unresectable, or metastatic colorectal cancer
Bristol-Myers Squibb· ROSETTA CRC-203
Reviewed by Blane Jackson, DDS, MBA. Educational analysis only. Read the editorial policy and disclosures.
NCT07221357 on ClinicalTrials.gov →Study type
interventional
Design
Randomized, double-blind, phas…
Target enrollment
990
Est. completion
2030-02-02
Investor scorecard
Probability of success
low
Timeline to catalyst
The trial started in late 2025 and is expected to complete by 2030. The phase 2 portion may have an interim analysis around 2027-2028, which could provide an early signal of efficacy. If the phase 2 results are positive, the trial may proceed to phase 3, with final results expected around 2030. Investors should watch for press releases on phase 2 data or interim analyses.
Potential stock impact
SignificantThe probability of success is low because immunotherapy has historically failed in the majority of colorectal cancer patients (MSS). Pumitamig is a novel bispecific antibody, but there is no prior clinical data in colorectal cancer, and the trial is large and long. The comparator (bevacizumab + chemo) is an effective standard, so pumitamig must show a clear improvement. Given the high failure rate of drugs in phase 2/3 trials for solid tumors, especially in this indication, the probability of success is estimated at around 15-20%.
What is being tested?
This trial is testing a new drug called pumitamig, which is a type of immunotherapy that helps the immune system fight cancer. It is being tested in patients with colorectal cancer that has spread (metastatic) or cannot be removed by surgery. The drug is given together with standard chemotherapy (FOLFOX, FOLFIRI, or CAPOX). The goal is to see if pumitamig plus chemotherapy works better than the current standard of care, which is bevacizumab (a drug that blocks blood vessel growth to tumors) plus the same chemotherapy options.
How does the trial work?
This is a randomized, double-blind trial, meaning patients are assigned by chance to receive either pumitamig or bevacizumab, and neither the patient nor the doctor knows which one they are getting. The trial has two phases: phase 2 will first determine the best dose of pumitamig and get an early read on efficacy, then phase 3 will confirm if it is better than the standard. Patients will receive treatment in cycles, typically every two or three weeks, and will be monitored with imaging scans and blood tests. They will continue treatment as long as they are benefiting and side effects are manageable. The trial is expected to enroll 990 patients at multiple sites worldwide.
What does success look like?
Success would be if pumitamig plus chemotherapy significantly improves outcomes compared to bevacizumab plus chemotherapy. The main measures are: 1) Objective response rate (ORR) – the percentage of patients whose tumors shrink or disappear. For colorectal cancer, an ORR of around 40-50% is typical with current treatments, so a higher ORR would be promising. 2) Progression-free survival (PFS) – the time patients live without the cancer growing. Current first-line treatments for metastatic colorectal cancer have a median PFS of about 10-12 months, so a meaningful improvement (e.g., 2-3 months) would be considered a win. 3) Overall survival (OS) – the ultimate goal, with current median OS around 30 months. A significant improvement in OS would be the strongest evidence of benefit.
What it means for investors
For investors, this trial is a major catalyst for Bristol-Myers Squibb. If the phase 2 portion shows a clear signal of improved efficacy and a manageable safety profile, it could boost confidence and potentially lead to accelerated development. Positive phase 3 results would likely lead to regulatory submissions and eventual approval, opening a significant market opportunity in first-line metastatic colorectal cancer, which is a large patient population. However, the trial is long (expected completion in 2030), so near-term catalysts are limited to interim analyses and phase 2 data readouts. If the trial fails, it would be a setback for BMS's pipeline, but the company has other assets to mitigate the impact. The stock impact could be significant if results are positive, but given the long timeline, it may be more of a slow-burn catalyst.
Trial endpoints
Primary endpoints
Secondary endpoints
Comparator
Bevacizumab (Avastin) in combination with chemotherapy (FOLFOX, FOLFIRI, or CAPOX)
Competitive landscape
Colorectal cancer is the third most common cancer worldwide, with over 1.9 million new cases annually. In the metastatic setting, first-line treatment typically involves chemotherapy plus a targeted agent like bevacizumab or an EGFR inhibitor (if RAS wild-type). The market for first-line metastatic colorectal cancer is substantial, with global sales of bevacizumab (Avastin) exceeding $7 billion at its peak. Newer immunotherapies have shown limited efficacy in the majority of colorectal cancers (microsatellite stable), so there is a high unmet need for treatments that work in this population. If pumitamig can demonstrate improved outcomes over bevacizumab, it could capture a significant share of this multi-billion dollar market.
| Drug | Sponsor | Phase | Differentiation |
|---|---|---|---|
| encorafenib + cetuximab (Braftovi + Erbitux) | Pfizer / Merck KGaA | Phase 1 | Targets BRAF V600E-mutant colorectal cancer, a specific subset, not all patients. |
| trastuzumab deruxtecan (Enhertu) | Daiichi Sankyo / AstraZeneca | Phase 1 | For HER2-positive metastatic colorectal cancer, another biomarker-driven subset. |
| fruquintinib (Fruzaqla) | Takeda | Phase 1 | Approved for previously treated metastatic colorectal cancer, not first-line. |
| botensilimab + balstilimab | Agenus | Phase 1 | Combination of two immunotherapies (anti-CTLA-4 and anti-PD-1) being tested in colorectal cancer, including microsatellite stable tumors. |
| etigilimab (anti-TIGIT) | Compugen | Phase 1 | Another immunotherapy targeting TIGIT, being tested in combination with PD-1 inhibitors in colorectal cancer. |
Historical context
Prior trial results
Pumitamig is a bispecific antibody that targets both CD3 on T cells and a tumor-associated antigen (likely DLL3 or similar, but not specified). It has been studied in earlier-phase trials for other solid tumors, showing manageable safety and preliminary antitumor activity. However, no prior results in colorectal cancer have been reported publicly. This is the first trial in colorectal cancer, so there is no prior efficacy data in this indication.
Regulatory history
No regulatory designations (e.g., fast track, breakthrough) have been announced for pumitamig in colorectal cancer. The drug is still in early development, and this trial is a phase 2/3, which may allow for accelerated approval if phase 2 results are compelling.
Similar drug precedents
Immunotherapies like PD-1/PD-L1 inhibitors have revolutionized treatment for many cancers, but in colorectal cancer, they are only effective in the small subset (about 5%) with microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) tumors. For the majority (microsatellite stable, MSS), checkpoint inhibitors have failed to show benefit. Bispecific T-cell engagers (like blinatumomab) have shown success in hematologic malignancies but have been challenging in solid tumors due to toxicity and limited tumor penetration. However, newer formats like pumitamig are designed to overcome some of these hurdles. If pumitamig can show activity in MSS colorectal cancer, it would be a major breakthrough.