Story of Santosh Khurrana

63-year-old Santosh Khurrana (name changed) felt the symptoms related to lung cancer and went for a consultation with Dr. Shyam Aggarwal. Before starting the therapy, he decided to test Santhosh for presence of genetic mutation/s.

The tissue sample (FFPE block) was sent to MedGenome Labs, Bangalore for genetic sequencing. The report showed exon 19 deletion in EGFR gene. Presence of this mutation in the tumor confers sensitivity to first and second-generation EGFR tyrosine kinase inhibitors (TKIs): Gefitinib, Erlotinib and Afatinib. After confirmation of EGFR exon 19 deletion, patient was started on gefitinib therapy and as expected, Santosh showed improvement, symptomatically.

To Dr Aggarwal’s surprise, Santosh stopped responding to the treatment in a couple of months. Again, molecular testing was attempted to identify any resistant mutation acquired by the patient. The report revealed secondary mutation: EGFR-T790M which renders the patient resistant to first/second generation TKIs (Gefitnib/Erlotinib/Afatinib). Reacting quickly to this finding, Dr Aggarwal changed the therapy to third generation TKI- Osimertinib and as expected, Santosh once again showed improvement, symptomatically.

The response of Osimertinib started to decline as well. A follow up molecular testing report showed found EGFR-C797S mutation. Presence of this mutation developed acquired resistance to Osimertinib. A deep-dive in the mutation type showed a mutation in cis-transformation with T790M.

Based on the finding, MedGenome suggested a unique combination of Brigartinib and anti-EGFR antibody. A study has shown that combination therapy of Brigatinib and anti-EGFR antibody is a powerful candidate to overcome Osimertinib resistance in triple-mutation-harboring cells (EGFR exon 19 deletion + T790M+C797S).

Summary

• Genetic testing reveals, step by step, a mutation that renders sensitivity and later a mutation that renders resistance for first and second generation TKIs
• Later genetic testing reveals a mutation that renders resistance to third generation TKIs
• MedGenome suggested a unique combination to overcome the resistance to third generation TKIs based on the findings

About MedGenomeMedGenome is a leading solution provider of clinical genomics which offers genetic testing across various disease areas like neurology, oncology, cardiology, rare inherited diseases, endocrinology, hematology, pre natal, population genomics etc. MedGenome's diagnostics tests include many breakthroughs for genetic diagnostics including liquid biopsy, non-invasive prenatal screening test (NIPT), carrier screening, and whole exome sequencing for cost-effective identification of rare mutations at its CAP certified lab in Bangalore.

Medgenome offers	Test Code	Test Sample requirements	TAT
Comprehensive tumor gene panel		Test requisition form along with relevant clinical information including pedigree. consanguinity. age of onset, clinical presentation and symptoms	21 Working days