Trial results for pembrolizumab (Keytruda) in patients with mismatch repair deficient locally advanced solid cancers were posted on ClinicalTrials.gov on 2025-05-13. The Phase 2 study (NCT04082572) showed a pathological complete response (pCR) rate of 67% when pembrolizumab was administered before surgery.
Background
The trial investigated pembrolizumab as a neoadjuvant treatment for mismatch repair deficient locally advanced solid cancers. These cancers are characterized by microsatellite instability-high (MSI-H) tumors, which have a greater than normal number of genetic markers called microsatellites and may have defects in the ability to correct m.
Trial design
The Phase 2 study (NCT04082572) titled "Pembrolizumab Before Surgery for the Treatment of Mismatch Repair Deficient Locally Advanced Solid Cancers" was completed with an enrollment of 35 participants. The trial investigated pembrolizumab as a neoadjuvant treatment for patients with locally advanced malignant solid neoplasms that are mismatch repair deficient.
Key results
The trial evaluated several outcomes for neoadjuvant pembrolizumab in localized MSI instability high/deficient mismatch repair solid tumors:
- The pathological complete response (pCR) rate was 67%.
- Safety was assessed in 35 participants.
- Post-surgical complications, as assessed by the Clavien-Dindo Classification, were observed in 3 participants.
- The overall response rate was observed in 27 participants.
- Radiographic tumor response to neoadjuvant pembrolizumab was observed in 27 participants.
What this means
The results from this Phase 2 trial suggest that pembrolizumab administered before surgery may induce a substantial pathological complete response in patients with mismatch repair deficient locally advanced solid cancers. A 67% pCR rate indicates a promising level of tumor regression at the time of surgery, which could have favorable implications for patient outcomes in this challenging cancer population. The safety profile, with 3 participants experiencing post-surgical complications, provides initial insights into the tolerability of this neoadjuvant approach.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT04082572, titled "Pembrolizumab Before Surgery for the Treatment of Mismatch Repair Deficient Locally Advanced Solid Cancers," were posted on 2025-05-13 on clinicaltrials.gov.