Trial results for a Phase 2 study (NCT05061017) investigating nivolumab in combination with pixatimod, with or without cyclophosphamide, for patients with PD-1 relapsed/refractory metastatic melanoma, non-small cell lung cancer (NSCLC), and MSS metastatic colorectal carcinoma (mCRC) were posted on ClinicalTrials.gov on 2025-03-07. The study reported objective response rates (ORR) as high as 62.5 percentage of patients in certain cohorts.
Background
Nivolumab is an immunotherapy drug. This Phase 2 trial investigated its use in combination with pixatimod, and in some cohorts, with low-dose cyclophosphamide, for advanced cancers including PD-1 relapsed/refractory metastatic melanoma, non-small cell lung cancer (NSCLC), and MSS metastatic colorectal carcinoma (mCRC).
Trial design
The Phase 2 study (NCT05061017) was a completed trial that enrolled 13 participants. The trial investigated combinations of pixatimod plus nivolumab, and nivolumab, pixatimod, and low-dose cyclophosphamide. The study included three separate patient cohorts: Cohort 1 for MSS metastatic colorectal carcinoma (mCRC) in combination with low-dose cyclophosphamide; Cohort 2 for PD-1 relapsed/refractory metastatic melanoma; and Cohort 3 for PD-1 relapsed/refractory non-small cell lung cancer (NSCLC). The primary goal was to assess clinical response in these patient populations.
Key results
The trial assessed Objective Response Rate (ORR) and Response Per Immune-related Response Criteria across the study cohorts. Key findings include:
- Objective Response Rate (ORR):
- For the group identified as Pixatimod (PG545) + Nivolumab - Cohort 1, ORR was reported as 40 percentage of patients and also as 60 percentage of patients.
- For the group identified as Pixatimod (PG545) + Nivolumab + Cyclophosphamide - Cohort 2 & Cohort 3, ORR was reported as 37.5 percentage of patients and also as 62.5 percentage of patients.
- Response Per Immune-related Response Criteria:
- For the group identified as Pixatimod (PG545) + Nivolumab - Cohort 1, responses were reported as 0 percentage of patients, 40.0 percentage of patients, and 60.0 percentage of patients.
- For the group identified as Pixatimod (PG545) + Nivolumab + Cyclophosphamide - Cohort 2 & Cohort 3, responses were reported as 12.5 percentage of patients, 37.5 percentage of patients, and 50.0 percentage of patients.
- Response Per Immune-related Response Criteria - Combined Study Population (Cohorts 1, 2 & 3):
- Responses were reported as 8 percentage of patients and also as 38 percentage of patients.
Statistical analyses included two instances using the Fisher Exact method, both reporting a p-value of 1 (95.0% CI).
What this means
The trial results indicate that combinations of nivolumab with pixatimod, with or without cyclophosphamide, elicited objective responses and immune-related responses in some patients with advanced melanoma, NSCLC, and mCRC. The observed response rates varied across cohorts and outcome definitions, with some cohorts showing up to 62.5 percentage of patients achieving an objective response. The statistical analyses reported a p-value of 1 for the Fisher Exact method, which suggests that the observed differences were not statistically significant based on this analysis.
Source
The information for this article was sourced from ClinicalTrials.gov, a public registry of clinical studies. The results for study NCT05061017, titled "Pixatimod (PG545) Plus Nivolumab in PD-1 Relapsed/Refractory Metastatic Melanoma and NSCLC and With Nivolumab and Low-dose Cyclophosphamide in MSS Metastatic Colorectal Carcinoma (mCRC)," were posted on 2025-03-07 on clinicaltrials.gov.