OncQuest Laboratories Ltd, a pioneer in oncology clinical testing in India, has launched TPMT genotyping - an effective tool for predicting therapeutic response of thiopurine drugs - in patients on treatment for acute lymphoblastic leukaemia (ALL), irritable bowel syndrome (IBS or Crohn's disease) and solid organ transplants.

Speaking to Pharmabiz, Aditya Burman, managing director of OncQuest Laboratories said, "Based on our long existence in this niche space, we understand the need for an effective diagnosis for ALL and IBS patients. The TPMT (thiopurine methyltransferase) genotyping identifies all four genetic variants, which affect the activity of the TPMT enzyme in more than 95 per cent cases. These variations have been known to cause differing responses to thiopurine drugs, hence understanding the variations would help the clinicians in determining the effective dosage for each individual patient. As ever, our endeavour is to equip the clinicians for accurate diagnosis and treatment."

These tests will be available at all the patient service centres of OncQuest Laboratories including 45 major towns in India, Colombo and Kathmandu.

OncQuest Laboratories' new technologically advanced clinical and research laboratory is fully equipped with molecular technologies allowing for rapid advancement in the complex field of theranostics, pharmacogenomics, companion diagnostics, proteomics, bioinformatics and biomarker studies.

Thiopurine drugs (azathiopurine, 6-mercaptopurine, and 6-thioguanine) are used to treat patients with ALL, IBS or solid organ transplants. To exert their therapeutic effect; thiopurine drugs require conversion to thioguanine nucleotides. However, that conversion can be blocked by methylation or oxidation. The methylation pathway depends on thiopurine methyltransferase (TPMT) activity, an enzyme whose concentration varies among individuals. Thioguanine nucleotides can accumulate in those patients who have reduced TPMT activity and still are receiving standard thiopurine doses, thus resulting in haematopoietic toxicity (e.g., myelosuppression). Dosage reduction can minimize toxicity in such patients. Reduced TPMT activity is caused by genetic variation in the TPMT gene. Thus genotype analysis of TPMT can thus help identify patients who are at increased risk of haematological drug toxicity.

The key element of OncQuest's services has been in establishing several new technologies and making these commercially available for the first time in India. The company has introduced a number of techniques to evaluate the structure of DNA, RNA and proteins in cells. The most common methods used in the clinical setting include: Polymerase Chain Reaction (PCR); Real Time PCR; Fluorescent -In-Situ- Hybridization (FISH); Cytogenetics; Flowcytometry; Immunohistochemistry and routine surgical pathology.