therascreen FGFR RGQ RT-PCR Kit

• Detection of four point mutations and two fusions in the FGFR3 gene 
• High sensitivity and specificity 
• Simple workflow with next-day results
• Automated data analysis using Rotor-Gene AssayManager v2.1 software  

The therascreen FGFR RGQ RT-PCR Kit is a qualitative in vitro diagnostic test for the detection of two point mutations in exon 7 [p.R248C (c.742C>T), p.S249C (c.746C>G)], two point mutations in exon 10 [p.G370C (c.1108G>T) and p.Y373C (c.1118A>G)] and two fusions (FGFR3-TACC3v1 and FGFR3-TACC3v3) in the FGFR3 gene.

The therascreen FGFR RGQ RT-PCR Kit is a companion diagnostic (CDx) test for the identification of patients with cases of urothelial cancer (UC) that harbor these actionable FGFR alterations, and for whom treatment with erdafitinib is indicated.

Trial 42756493-BLC3001 was a phase 3 study to demonstrate superiority of erdafitinib over established (chemotherapy) and emerging (anti-PD-L1/PD-L1 monoclonal antibodies) standard of care options in relapsed/refractory subjects with selected FGFR alterations (1).

During the study, erdafitinib was compared to vinflunine or docetaxel (cohort 1) or pembrolizumab (cohort 2) in subjects with advanced urothelial cancer and selected FGFR mutations. The primary endpoint of OS (overall survival) was evaluated in two cohorts:

• Cohort 1: Erdafitinib versus chemotherapy (docetaxel or vinflunine) in subjects who have received prior anti-PD(L)-1 agent
• Cohort 2: Erdafitinib versus pembrolizumab in subjects who have not received prior anti-PD(L)-1 agent

This study was conducted using the therascreen FGFR RGQ RT-PCR Kit to screen patients for an FGFR mutation. Only cohort 1 was used for registration purposes.

For all observed FGFR mutation-positive (FGFR+) subjects in cohort 1, the primary efficacy endpoint of OS showed a statistically significant improvement in OS for subjects treated with erdafitinib vs chemotherapy (HR: 0.628; 95% CI: 0.438, 0.900; p-value: 0.0106). This represents a 37.2% reduction in the risk of death for subjects in the erdafitinib vs the chemotherapy treatment group. In the erdafitinib group, median OS was 10.94 months (95% CI: 10.12, 16.76). In the chemotherapy group, median OS was 7.72 months (95% CI: 6.54, 11.30). These results demonstrated comparable efficacy with the drug intention-to-treat population (HR: 0.64; 95% CI: 0.47, 0.88). Full efficacy results for the FGFR+ population within the cohort 1 analysis set are shown in Table 1 (1).

NE: Not estimable. 
* Censored observation. 
† p value from a log-rank test.
‡ Hazard ratio (HR) from unstratified proportional hazards model. HR <1 favors erdafitinib.

The therascreen FGFR RGQ RT-PCR Kit is therefore indicated for use as an aid in identifying patients with cases of urothelial cancer that harbor FGFR alterations and are therefore eligible for treatment with erdafinitib.

The therascreen FGFR RGQ RT-PCR Kit is based on the selective amplification of alterations in the FGFR3 gene using the Rotor-Gene Q MDx 5plex HRM instrument for sensitive and specific analysis. The assay exploits the qPCR oligonucleotide hydrolysis principle using TaqMan probes.

Allele-specific technology allows accurate and highly reproducible detection of alterations, based on the use of specific forward and reverse primers and probes; only a perfect match between the primers and probes with the target cDNA allows extension and amplification in the PCR reaction. Result reporting is fully automated. If both the positive and no template controls are valid and the sample internal controls are valid, the FGFR alteration status will be displayed in the software.

The fast and simple workflow takes ~12 hours from Sample to Insight.

RNA is first prepared from formalin-fixed paraffin-embedded (FFPE) urothelial tumor samples using the RNeasy DSP FFPE Kit. Purified RNA is then reverse transcribed using Reverse Transcriptase to generate cDNA for real-time PCR analysis. Optimized reverse transcription reagents and PCR master mixes provided in the kit enable high-fidelity reverse transcription and sensitive real-time PCR on the Rotor-Gene Q MDx 5plex HRM instrument. Qualitative results are displayed in Rotor-Gene AssayManager software, informing the system operator if one or more of the four point mutations and two fusions in the FGFR3 gene detected by the kit are present in each sample.

The therascreen FGFR RGQ RT-PCR Kit enables qualitative detection of four point mutations and two fusions of the FGFR3 gene for in vitro diagnostic use. It is the only approved CDx assay for the selection of patients with cases of urothelial cancer (UC) harboring actionable alterations, for whom treatment with erdafitinib is indicated. 

1. therascreen FGFR RGQ RT-PCR Kit Instructions for Use. June 2025