Advice

The technology

The technology

Spartan RX CYP2C19 System (Genomadix) is a point-of-care DNA test used to detect mutations in the CYP2C19 gene, specifically the *2, *3 and *17 alleles. CYP2C19 gene mutations impair response to medicines metabolised by CYP2C19, such as the antiplatelet drug clopidogrel. Clopidogrel is commonly prescribed after percutaneous coronary interventions (PCIs). People with an impaired response to clopidogrel can go on to have adverse cardiovascular events. Testing with Spartan RX aims to identify these people based on their CYP2C19 genotype. They can then be offered alternatives to clopidogrel.

The technology comprises:

  • Spartan RX Platform. This contains the Spartan RX Analyser or thermal cycling instrument for polymerase chain reaction (PCR) amplification, the Netbook user interface, and a printer and barcode scanner for automatically entering collection kit lot numbers.

  • Spartan transport system. This is an insulated transport bag containing a polystyrene box and a cold block designed to keep collection kits and samples cold before analysis.

  • Spartan RX assays (sample collection kit and external control kit). This contains all the consumables needed to determine CYP2C19 genotype, including a reagent tube, a buccal swab, and a pouch with labelling information and a barcode. There are 3 different colour-coded collection kits to be used (one each for CYP2C19 *2, *3 and *17 genotype assays).

The test uses a buccal sample taken using a buccal swab. Samples are inserted into a reagent tube and placed into the transport system until the sample is ready to be analysed. The samples are then run on the Spartan RX system, which combines and automates DNA extraction, PCR amplification, and fluorescence-based detection of CYP2C19 alleles.

The test is not intended to be used to predict drug response or non-response. The test result should be used together with standard clinical decision making alongside routine monitoring.

The company has released a successor to the Spartan RX device called the Spartan Cube. The Spartan Cube differs from Spartan RX in that the 3 reaction tubes are integrated into a single test cartridge, the swabs and test cartridges are packaged separately, and the DNA analyser device is smaller.

Innovations

The innovative aspect of the technology is that it is a point-of-care test. The test can be done at the time of PCI and results can be available within 55 minutes. The test does not require any specialised laboratory experience or training, and can be used directly by attending healthcare professionals. The test does not require sample preparation and results are given without the need for data interpretation. Current CYP2C19 genotyping tests are processed in central laboratories and require a follow-up appointment to receive the results and adjust the patient's therapy, if needed.

Current care pathway

Patients presenting with acute coronary syndrome who are having PCI are typically prescribed dual antiplatelet therapy, consisting of aspirin and a P2Y12 receptor inhibitor, to prevent major adverse cardiovascular events. Antiplatelet therapy is started before or at the time of PCI and continued for 12 months afterwards.

People with ST-segment elevation myocardial infarction (STEMI) should be offered the P2Y12 receptor inhibitors prasugrel or ticagrelor with aspirin. Clopidogrel is recommended when ticagrelor and prasugrel are not available or are contraindicated.

People with unstable angina or non-ST-segment-elevation myocardial infarction (NSTEMI) having PCI should also be offered prasugrel or ticagrelor with aspirin.

There are no explicit recommendations around routine CYP2C19 genotype testing or genotype-guided therapy in these patients, and no particular tests have been recommended.

The following publications have been identified as relevant to this care pathway:

Population, setting and intended user

The population is people with acute coronary syndromes having PCI who need antiplatelet therapy. In 2017 to 2018, 102,258 PCI procedures were done in 118 PCI centres in the UK (National Audit for PCI, 2019).

Clopidogrel is a widely prescribed P2Y12 receptor inhibitor for dual antiplatelet therapy in people having PCI, although 2% to 14% of the population do not metabolise it well. This is primarily because of mutations in the CYP2C19 gene, and Spartan RX aims to help guide treatment in these people. The test would be done in secondary care by an interventional cardiologist at the time of the PCI procedure.

Costs

Technology costs

There is a capital equipment cost of £10,000 for the platform plus £175 per test for consumables (excluding VAT). Spartan RX and cube products are priced similarly.

Costs of standard care

Standard care involves antiplatelet therapy without the use of CYP2C19 genotype testing.

Resource consequences

Spartan RX is not yet used in the NHS. If adopted, Spartan RX would initially cost more than standard care, which does not currently use CYP2C19 genotype testing. However, a tailored antiplatelet approach using the test may be resource releasing if genotype-guided therapy using the test leads to improved outcomes for patients (such as a reduced incidence of acute stent thrombosis) compared with prescribing clopidogrel empirically or selecting an alternative antiplatelet agent. This is not fully supported by the available evidence. There is evidence of a reduced incidence of minor bleeding, and non-inferiority to standard therapy for thrombotic events. But Spartan RX has not been shown to be better than standard therapy in terms of reducing thrombotic events. The company says that the technology is designed to be used without extensive laboratory training but it does provide free training if needed.