therascreen KRAS RGQ PCR Kit

• FDA-approved CDx for LUMAKRAS or KRAZATI in non-small cell lung cancer (NSCLC)
• FDA-approved CDx for KRAZATI in combination with ERBITUX, ERBITUX alone or Vectibix in colorectal cancer (CRC)
• Reliable detection of 7 mutations in the KRAS gene
• Ready-to-use system with simple workflow and next-day results
• Automated data analysis using Rotor-Gene Q software
  
  

The therascreen KRAS RGQ PCR Kit is a real-time, qualitative in vitro diagnostic test for the detection of 7 somatic mutations in the KRAS oncogene using a sample of DNA extracted from formalin-fixed, paraffin-embedded (FPPE) non-small cell lung cancer (NSCLC) tissue and colorectal cancer (CRC) tissue.

NSCLC: The therascreen KRAS RGQ PCR Kit is an FDA-approved companion diagnostic (CDx) PCR test intended to aid in the identification of NSCLC patients for treatment with LUMAKRAS (sotorasib) or KRAZATI (adagrasib) based on a KRAS G12C Mutation Detected result. CRC: The therascreen KRAS RGQ PCR Kit is an FDA-approved companion diagnostic (CDx) PCR test intended to aid in the identification of CRC patients for treatment with KRAZATI (adagrasib) in combination with Erbitux (cetuximab) based on a KRAS G12C Mutation Detected result. In addition, the kit is also an FDA-approved CDx test to aid in the selection of patients with CRC who may be eligible for treatment with Erbitux (cetuximab) or Vectibix (panitumumab), based on a KRAS No Mutation Detected test result. 

Clinical study supporting use with LUMAKRAS (sotorasib) in NSCLC¹

A clinical performance study demonstrated the clinical validity of the therascreen KRAS RGQ PCR Kit as a CDx test to aid the identification of NSCLC patients for treatment with LUMAKRAS (sotorasib). The objective of the study was to assess whether G12C mutation status, as determined by the therascreen KRAS RGQ PCR Kit, can be used to select patients with advanced NSCLC that will benefit from LUMAKRAS (sotorasib) treatment. Clinical trial 20170543 is an ongoing open-label, multicenter, phase 1/2 study designed to evaluate the efficacy and safety of LUMAKRAS (sotorasib) in adult subjects with advanced solid tumors that harbor the KRAS G12C mutation. Data from the primary analysis of the NSCLC phase 2 portion of this study has been used to support the clinical validity of the therascreen KRAS RGQ PCR Kit as a CDx test. Enrollment was restricted to subjects with KRAS G12C-mutated NSCLC as assessed by a local laboratory result, which was confirmed by central testing using the therascreen KRAS RGQ PCR Kit.

The primary endpoint of the NSCLC phase 2 portion of this study was to evaluate tumor objective response rate (ORR) assessed by RECIST 1.1 criteria of LUMAKRAS (sotorasib) as monotherapy in subjects with KRAS G12C-mutated advanced tumors.

Analysis was performed on 124 patients. The primary endpoint of ORR (complete response + partial response) was assessed by blinded independent centralized review (BICR) using RECIST 1.1. For subjects with KRAS G12C-mutated NSCLC ORR was 35% (45 of 124 subjects; 95% CI: 28-45%); 2% (two subjects) achieved complete response and 35% (43 subjects) achieved partial response.

Clinical study supporting use with KRAZATI (adagrasib) in NSCLC¹

A bridging study demonstrated the clinical efficacy of the therascreen KRAS RGQ PCR Kit as a CDx test to aid the identification of NSCLC patients for treatment with KRAZATI (adagrasib) based on a KRAS G12C mutation detected test result. The results were compared with the clinical efficacy observed in Cohort A of a clinical trial 849-001. Clinical efficacy was evaluated by assessing the ORR for KRAS G12C mutation detected, KRAS G12C mutation non-detected and KRAS G12C mutation non-evaluable subjects separately.

The clinical trial 849-001 was a phase 1/2 multiple expansion cohort trial of KRAZATI (adagrasib) in patients with advanced solid tumors with KRAS G12C mutation. The primary objective of the trial was to characterize the safety and tolerability of KRAZATI (adagrasib) in patients having advanced solid tumor malignancies with the KRAS G12C mutation and to evaluate the pharmacokinetics of KRAZATI (adagrasib). Cohort A enrolled patients with advanced NSCLC with KRAS G12C mutation who had previously received treatment with a platinum-based regimen and an immune checkpoint inhibitor. The primary endpoint for evaluation of efficacy was overall response rate (ORR), in accordance with RECIST version 1.1.

In total, FFPE tissue specimens from 218 unique subjects (104 from Cohort A and 114 procured) were sent to a central laboratory for KRAS G12C testing with the therascreen KRAS RGQ PCR Kit. Two specimens were from the same procured subject, therefore, in total 219 specimens were tested for KRAS G12C mutation status. Three samples from Cohort A had either no tumor or insufficient sample for the testing. Of the 216 testable samples, 210 produced evaluable results. Of the 218 unique subjects, 209 produced evaluable results. None of the procured clinical KRAS G12C-negative specimens tested KRAS G12C positive when testing with the therascreen KRAS RGQ PCR Kit.

Table 1. Concordance between therascreen KRAS RGQ PCR Kit (CDx) and clinical trial enrollment assays (CTA)

Based on the clinical bridging study, the positive percent agreement (PPA) and the negative percent agreement (NPA) between the therascreen KRAS RGQ PCR Kit (CDx) and the clinical trial enrollment assays (CTA) were calculated (PPA: 88.78%; NPA: 100%). An NPA of 100% indicated that the final estimated drug efficacy (ORR) for the KRAS G12C mutation positive patients tested by CDx in the intended use population is the same as the estimated drug efficacy of the CDx-positive patients observed in Cohort A primary efficacy population in the 849-001 clinical trial.

The efficacy of the therascreen KRAS RGQ PCR Kit, in identifying patients as KRAS G12C mutation detected for treatment with KRAZATI (adagrasib) was demonstrated. The primary endpoint of ORR in KRAS G12C mutation-detected patients with measurable disease was 43% (36/83, 95% CI: 33%, 55%) which exceeded the hypothesized response rate of 23% reported with standard care and met the study acceptance criteria.

Clinical study supporting use with KRAZATI (adagrasib) in combination with Erbitux (cetuximab) in CRC¹ 

A bridging study was conducted to evaluate the clinical utility of the therascreen KRAS RGQ PCR Kit when used a companion diagnostic (CDx) to identify patients diagnosed with metastatic CRC (mCRC) for treatment with KRAZATI (adagrasib) with cetuximab based on a positive KRAS G12C mutation test result. Results of the bridging study were compared with the clinical efficacy observed in a Phase 1/2 clinical trial (849-001; KRYSTAL 1). Clinical efficacy was evaluated by assessing the overall response rate (ORR) of subjects enrolled into the Phase 1 sub-study and Phase 2 cohort G.

KRYSTAL 1 clinical trial was a phase 1/2 multiple expansion cohort trial of KRAZATI (adagrasib) with cetuximab in patients with advanced solid tumors with KRAS G12C mutation. CRC patients were enrolled into the Phase 1 sub- study, the Phase 1b dose optimization cohort and Phase 2 Cohort G. The primary objective of the trial was to characterize the safety and tolerability of KRAZATI (adagrasib) in patients with advanced solid tumor malignancies and KRAS G12C mutation and to evaluate the pharmacokinetics of KRAZATI (adagrasib). The primary endpoint for evaluating clinical efficacy was ORR based on RECIST version 1.1. 

The bridging study was conducted to establish concordance between the therascreen KRAS RGQ PCR Kit (the CDx) and the CTA used in the trial, as determined by a comparison of ORR for KRAS G12C-positive and -negative cohorts. 

Samples from 121 KRAS G12C-positive subjects with mCRC tested with a CTA were enrolled into Phase 1 sub-study (32 subjects), Phase 1b dose optimization (27 subjects) and Phase 2 Cohort G (62 subjects) of KRYSTAL 1. Of these 121 subjects, 35 samples (14 Phase 1, 7 Phase 1b and 14 Phase 2) were not evaluable, either due to insufficient tumor tissue or no consent for further testing and were not evaluated using the therascreen KRAS RGQ PCR Kit or included in efficacy analysis. The 86 testable samples from Phase 1/2 were supplemented with an additional 91 mCRC samples with KRAS G12C not detected results procured from commercial vendors. In total, FFPE tissue specimens from 177 unique subjects (86 from Phase 1/2 of KRYSTAL 1 and 91 procured) were sent to a central laboratory for KRAS G12C testing with the therascreen KRAS RGQ PCR Kit. Of the 177 samples, 171 produced evaluable results. 

Based on the clinical bridging study, the positive percent agreement (PPA) and the negative percent agreement (NPA) between the therascreen KRAS RGQ PCR Kit (CDx) and the clinical trial assay (CTA) were calculated (PPA: 92.50%; NPA: 100%) as shown in Table 2. Concordance between CTA and CDx is based on CTA as a reference method. 

Table 2. Concordance between therascreen KRAS RGQ PCR Kit (CDx) and clinical trial enrollment assays (CTA) 

* 95% CI calculated using the Exact (Clopper-Pearson) method. 

Effectiveness of the therascreen KRAS RGQ PCR Kit (CDx) in identifying mCRC patients as KRAS G12C mutation detected for treatment with KRAZATI (adagrasib) and cetuximab was demonstrated using subjects from the primary efficacy population. The primary endpoint of ORR in CDx KRAS G12C mutation detected patients with measurable disease in the bridging study was 34.6% (19/55, 95% CI: 22.2%, 48.6%). This value exceeded the acceptance criteria from KRYSTAL-1 (i.e., the hypothesized response rate of 5% reported with standard care) and was comparable to the ORR value seen in KRYSTAL-1 (34.0%). 

Clinical study supporting use with Erbitux (cetuximab) in CRC¹

A clinical performance study generated data supporting the clinical utility of the therascreen KRAS RGQ PCR Kit as a CDx test to enable selection of patients for treatment with Erbitux (cetuximab). Study CA225025 was a multicenter, open-label, randomized clinical trial conducted in 572 patients with EGFR-expressing, previously treated, metastatic CRC (mCRC). Patients were randomized (1:1) to receive either Erbitux (cetuximab) plus best supportive care (BSC) or BSC alone. Erbitux (cetuximab) was administered as a 400 mg/m² initial dose, followed by 250 mg/m² weekly until disease progression or unacceptable toxicity.

KRAS mutation status was available for 453 (79%) patients. 245 (54%) patients had KRAS mutation-negative tumors and 208 (46%) patients had KRAS mutation-positive tumors as assessed using the therascreen KRAS RGQ PCR Kit.

The main outcome measure of the study was overall survival (OS) (Table 3). For the KRAS mutation-negative (wild-type) population, median survival time was 8.6 months (95% CI: 7.0, 10.3) months in the Erbitux (cetuximab)+BSC group and 5.0 months (95% CI: 4.3, 5.7) in the BSC alone group. For the KRAS mutation-positive population, median survival time was 4.8 months (95% CI: 3.9, 5.6) in the Erbitux (cetuximab)+BSC group and 4.6 months (95% CI: 3.6, 4.9) in the BSC alone group.

Table 3. Overall survival in previously treated EGFR-expressing mCRC

Overall survival rates based on Kaplan-Meier estimates at months 6 and 12 were higher for the Erbitux (cetuximab)+BSC group than the BSC group for the KRAS wild-type subset. This advantage was not observed in the KRAS mutant subset.

Clinical study supporting use with Vectibix (panitumumab) in CRC¹

A clinical performance study generated data supporting the clinical utility of the therascreen KRAS RGQ PCR Kit as a CDx test to enable selection of patients for treatment with Vectibix (panitumumab). The objective of the study was to assess whether KRAS mutation status as determined by the therascreen KRAS RGQ PCR Kit can be used to select patients with mCRC who will benefit from Vectibix (panitumumab) treatment. Clinical trial 20050203 was a multicenter, prospective, open‐label, randomized phase 3 study to assess the efficacy of panitumumab in combination with oxaliplatin, 5‐fluorouracil (5‑FU) and leucovorin (FOLFOX4) vs. FOLFOX4 alone in patients with previously untreated mCRC.

Banked tumor samples from patients in study 20050203 were tested with the therascreen KRAS RGQ PCR Kit to identify two subgroups: KRAS mutation-positive (mutant KRAS) and KRAS mutation-negative (wild-type KRAS), according to whether at least one or none of 7 KRAS mutations in codons 12 and 13 of exon 2 in the KRAS gene was detected. In retrospective analyses, efficacy data from study 20050203 were stratified by KRAS subgroup. The primary objective of the KRAS analysis was to assess whether an overall improvement in progression-free survival (PFS) for Vectibix (panitumumab) plus FOLFOX relative to FOLFOX alone was significantly greater among subjects with KRAS wild‐type tumors compared to subjects with KRAS mutant tumors.

The prespecified primary efficacy endpoint was PFS in the group of patients (n = 656) with wild-type KRAS mCRC as assessed by blinded independent central review (BICR) of imaging (Table 4). Other key efficacy endpoints included overall survival (OS) and objective response rate (ORR).

Table 4. Efficacy results in patients with wild-type KRAS mCRC

In patients with KRAS mutant tumors, median PFS was 7.3 months (95% CI: 6.3, 8.0) in the 221 patients receiving Vectibix (panitumumab) plus FOLFOX versus the median PFS of 8.8 months (95% CI: 7.7, 9.4) in the 219 patients who received FOLFOX alone (HR: 1.29, 95% CI: 1.04, 1.62). Median OS was 15.5 months (95% CI: 13.1, 17.6) in patients receiving Vectibix (panitumumab) plus FOLFOX versus median OS of 19.3 months (95% CI: 16.5, 21.8) in patients who received FOLFOX alone (HR: 1.24, 95% CI: 0.98, 1.57).

For more information regarding Erbitux, Vectibix, LUMAKRAS and KRAZATI indications, refer to the most recent drug labels at www.accessdata.fda.gov/scripts/cder/drugsatfda/index.cfm

The therascreen KRAS RGQ PCR Kit is comprised of 8 separate PCR amplification reactions: 7 mutation‑specific reactions in codons 12 and 13 of exon 2 of the KRAS oncogene and a wild‑type control in exon 4. Each mutation-specific reaction mix uses an amplification refractory mutation system (ARMS) primer to selectively amplify mutated DNA and then a Scorpions primer to detect the amplification product. If both the run controls and the sample results are valid, the therascreen KRAS RGQ PCR Kit qualitatively determines the mutation status of the DNA samples and reports if the sample contains one or more mutations.

The simple and straightforward testing workflow begins with manual DNA extraction from FFPE NSCLC or CRC tumor tissue using the QIAamp DSP DNA FFPE Tissue Kit, followed by sensitive real-time PCR on the Rotor-Gene Q MDx (US) instrument. Rotor-Gene Q software rapidly and accurately determines mutations and reports results, informing the system operator if one or more of the 7 mutations detected by the kit are present. The assay can be completed in ~8 hours, providing next-day results.

The therascreen KRAS RGQ PCR Kit enables qualitative detection of 7 mutations in codons 12 and 13 of the human KRAS gene (G12A, G12D, G12R, G12C, G12S, G12V, G13D) for in vitro diagnostic use. The kit is intended to discriminate between KRAS mutation-negative (wild-type) and KRAS mutant tumors.

The therascreen KRAS RGQ PCR Kit is an FDA-approved companion diagnostic (CDx) PCR test intended to aid in the identification of NSCLC patients for treatment with LUMAKRAS (sotorasib) or KRAZATI (adagrasib) and identification of patients with CRC for whom treatment with KRAZATI (adagrasib) in combination with Erbitux (cetuximab) or monotherapy with Erbitux (cetuximab) or Vectibix (panitumumab) may be appropriate.