PIK3CA mutation

PIK3CA is one of the most commonly mutated genes in HR+/HER2− advanced breast cancer.^1–5

PIK3CA mutations may lead to hyperactivation of PI3Kα, a key upstream component of the PI3K pathway.^1,13–16

Hyperactivation of the PI3K signalling pathway by PIK3CA mutations can result in acquired endocrine resistance in breast cancer cells.¹⁶

Combined endocrine and PI3K-directed treatment may overcome acquired resistance to endocrine therapy in HR+/HER2- advanced breast cancer.^16,17

Testing for the PIK3CA mutation

Early knowledge of a tumour’s PIK3CA mutation status should inform the patient’s treatment plan.    

• PIQRAY® (alpelisib) is indicated in combination with fulvestrant for the treatment of postmenopausal women, and men, with HR+/HER2−, locally advanced or metastatic breast cancer with a PIK3CA mutation after disease progression following endocrine-based therapy.¹⁸

PIK3CA testing can be an important component of aBC management

Only HR+/HER2- aBC patients whose tumour harbours a PIK3CA mutation are eligible for biomarker-driven therapy with PIQRAY® + fulvestrant.¹⁸

Patients with HR+/HER2- advanced breast cancer should be selected for treatment with PIQRAY® in combination with fulvestrant, based on the presence of a PIK3CA mutation in tumour or plasma specimens, using a validated test. If a mutation is not detected in a plasma specimen, tumour tissue should be tested if available.^†18

^†In SOLAR-1, PIK3CA mutation status was determined with PCR, and any alteration on exons 7, 9, or 20 qualified patients for enrolment in the PIK3CA mutation cohort.¹ For >90% of patients, the tissue tested was archival.¹⁹

aBC, advanced breast cancer; ER, oestrogen receptor; HER2–, human epidermal growth factor receptor 2-negative; HR, hormone receptor; PI3K, phosphoinositide 3-kinase; PIK3CA, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha; PCR, polymerase chain reaction; PFS, pre-filled syringe.

References     

1. André F, et al. N Engl J Med 2019;380(20):1929–1940.
2. Moynahan ME, et al. Br J Cancer 2017;116(6):726−730.
3. The Cancer Genome Atlas Network. Nature 2012;490(7418):61−70.
4. Zardavas D, et al. Breast Cancer Res 2014;16(1):201.
5. Kingston B, et al. Abstract GS3-07. Presented at SABCS 2019; 10-14 December 2019; San Antonio, Texas, USA.
6. Rugo HS, et al. Lancet Oncol 2021;22:489–498.
7. Mollon L, et al. Cancer Res 2018;78(suppl 13):Abstract 1207.
8. Mosele F, et al. Ann Oncol 2020;31:377–386.
9. Sobhani N, et al. J Cell Biochem 2018;119(6):4287–4292.
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11. Tolaney S, et al. Abstract 4458. Presented at AACR 2019 Annual Meeting; March 29–April 3, 2019; Atlanta, Georgia, USA.
12. Signorovitch J, et al. Abstract 1069. Presented at ASCO 2020; 29 May 2020; virtual meeting.
13. Al-Sukhun S, et al. Curr Breast Cancer Rep 2016;8:73−79.
14. Goncalves MD, et al. N Engl J Med 2018;379(21):2052−2062.
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16. Miller TW, et al. J Clin Invest 2010;120(7):2406−2413.
17. Mayer IA, et al. Clin Cancer Res 2017;23(1):26−34.
18. PIQRAY® (alpelisib) Summary of Product Characteristics. Novartis Pharma; December 2021.
19. Juric D, et al. Abstract GS3-08. Presented at SABCS; 4−8 December 2018; San Antonio, Texas, USA.