Concordance between the clinical trial assay (CTA) used to identify patients for recruitment to the Phase 2 clinical trial of BALVERSA (42756493-BLC2001) and the therascreen FGFR RGQ RT-PCR Kit (CDx) was evaluated in a bridging study (1).
Samples with valid results for both therascreen FGFR RGQ RT-PCR Kit and CTA (279/287 patients; 97.2%) were analyzed to assess the positive percent agreement (PPA), negative percent agreement (NPA) and overall percent agreement (OPA), based on agreement between the two methods for overall FGFR gene alteration status (i.e., FGFR Alteration Detected or FGFR Alteration Not Detected) Results are shown in Table 1.>
Table 1. therascreen FGFR RGQ RT-PCR Kit versus CTA (with CTA as reference method)
|Measure of agreement ||Percent agreement, % (N) ||Two-sided 95% CI |
|Positive percent agreement ||85.2% (69/81) ||75.9, 91.3 |
|Negative percent agreement* ||97.0% (192/198) ||93.5, 98.6 |
|Overall percent agreement ||93.5% (261/279) ||90.0, 96.1 |
* Prior chemotherapy information was not collected for CTA-negative patients. Therefore, 198 CTA-negative subjects included both chemo-relapsed/chemo-refractory patients and chemo-naïve patients.
The primary objective of the BLC2001 clinical trial was to evaluate the objective response rate (ORR) to treatment with BALVERSA in subjects with cases of UC in which FGFR alterations were detected. ORR was defined as complete response (CR) plus partial response (PR) by RECIST criteria, as assessed by blinded independent review committee (BIRC). The observed clinical benefit of treatment with BALVERSA in the subset of patients in which FGFR alterations were detected with both the therascreen FGFR RGQ RT-PCR Kit and the CTA (n = 69) was comparable to that observed in the full study population, as defined by the CTA only (n = 87). The ORR in patients in whom FGFR alterations were detected by both the therascreen FGFR RGQ RT-PCR Kit and the CTA, as assessed by BIRC, was 33.3% (95% CI: 23.4-45.1%).
The therascreen FGFR RGQ RT-PCR Kit is therefore indicated for use as an aid in identifying patients with cases of urothelial cancer which harbor these alterations and are therefore eligible for treatment with BALVERSA (erdafinitib).