NeoGenomics Laboratories, Inc., a cancer diagnostic and pharmaceutical services company based in Fort Myers, Florida, has published new data on the RaDar® assay as part of the second cohort of the phase 1b/2a NABUCCO trial. The trial is investigating patient response to neoadjuvant treatment with a CTLA-4 inhibitor (ipilimumab) in combination with a programmed cell death 1 ligand 1 inhibitor (nivolumab) among patients with locoregionally advanced urothelial cancer.
In both cohorts of the NABUCCO trial, the RaDar assay was used before and during neoadjuvant therapy as well as before surgery to assess circulating tumor DNA (ctDNA) in urine and blood plasma samples from patients to determine response to treatment.
The RaDar assay tracks up to 48 tumor-specific variants in cell-free DNA in a cancer patient’s blood plasma. The assay can detect minimal residual disease (MRD) after curative intent or definitive treatment, as well as early signs of relapse, and has been granted a Breakthrough Device designation by the US Food and Drug Administration for use in the detection of MRD in early-stage cancer.
The first cohort (n=24) tested the feasibility of neoadjuvant therapy with ipilimumab 3 mg/kg plus nivolumab 1 mg/kg and demonstrated high rates of pathologic complete response (pCR; a secondary end point). In the second cohort, patients were given either ipilimumab 3 mg/kg plus nivolumab 1 mg/kg (cohort 2A) or ipilimumab 1 mg/kg plus nivolumab 3 mg/kg (cohort 2B), both for 2 cycles, followed by nivolumab 3 mg/kg.
A total of 6 patients (43%) from cohort 2A and 1 patient (7%) from cohort 2B met the primary end point of complete pathological response. The absence of ctDNA in blood plasma was highly associated with both pCR (odds ratio, 45.0; 95% CI, 4.86-416.46) and progression-free survival (PFS; hazard ratio, 10.4; 95% CI, 2.86-37.50). In urine samples, the absence of ctDNA was linked to pCR but not PFS.
“Although cisplatin-based chemotherapy plus radical cystectomy remains the currently recommended treatment for muscle-invasive bladder cancer, there are some patients who are not eligible to receive chemotherapy, and the prognosis for this patient population is poor,” said Shashikant Kulkarni, chief scientific officer at NeoGenomics. “The findings from the NABUCCO trial offer initial evidence in hopefully improving the outlook for these patients. Importantly, the research shows that the RaDaR assay can be used successfully to guide decision-making and help oncologists personalize patient care based on their risk of recurrence.”