ClinicalTrials.gov posted results on 2026-08-18 for a terminated phase 2 trial of nivolumab in adults with recurrent, refractory rare central nervous system cancers. The study enrolled 136 participants and reported disease control rates of 21.9% in a heavily pre-treated cohort and 37.9% in a non-heavily pre-treated cohort.
Background
The trial evaluated nivolumab, described in the record as an immunotherapy drug intended to stimulate the immune system, in recurrent rare CNS tumors. The listed conditions were medulloblastoma, ependymoma, pineal region tumors, choroid plexus tumors, and atypical or malignant meningioma. The record states that more than 130 primary CNS tumors have been identified, that most affect fewer than 1,000 people in the United States each year, and that these tumors have few proven therapies.
Trial design
This was a phase 2 study with an enrollment of 136 participants. The intervention was nivolumab, and the record lists no comparator arm. Participants were reported in two groups: heavily pre-treated and non-heavily pre-treated. The stated objectives were to determine whether nivolumab could shrink tumors or increase the time before tumors grew or spread. No primary outcome measurements were listed in the supplied record.
Key results
For disease control, defined as complete response, partial response, or durable stable disease for six months, the heavily pre-treated cohort had a mean proportion of 0.219 with a standard deviation of 0.048. The non-heavily pre-treated cohort had a mean proportion of 0.379 with a standard deviation of 0.09. The same outcome was also posted as 21.9% and 37.9%, respectively, with 95% confidence intervals listed but no interval bounds supplied.
Median progression-free survival was 56.5 days in the heavily pre-treated cohort and 133 days in the non-heavily pre-treated cohort. Six-month progression-free survival was posted as 21.9% and 37.9%, respectively. Median overall survival was 1.62 years and 3.47 years. In the heavily pre-treated cohort, mean symptom-severity and symptom-interference scores were 1.94 and 2.92; these measures used the MD Anderson brain- and spine-tumor symptom modules.
The record lists six two-sample t-tests with p-values of 0.18, 0.11, 0.16, 0.09, 0.18, and 0.11, but does not identify the outcome associated with each analysis.
What this means
The posted results describe disease control and survival measures across two pre-treatment cohorts, without a comparator arm. The non-heavily pre-treated cohort had higher reported disease control and longer median progression-free and overall survival than the heavily pre-treated cohort, but the supplied record does not establish whether those differences were statistically significant or caused by nivolumab. No adverse-event summary was provided.
Source
This article is based on results posted by ClinicalTrials.gov on 2026-08-18. The source document is the ClinicalTrials.gov study record for NCT03173950, available at clinicaltrials.gov.