Around the world, almost 300,000 women are diagnosed with ovarian cancer each year.[i] In the United States, ovarian cancer is the fifth highest cause of cancer death among women, and while outcomes for patients have improved with the latest advances, the five-year survival rate for women with all types of ovarian cancer is still 47 percent.[ii]
Until recently, ovarian cancer was treated primarily by surgery and chemotherapy and, in some cases, radiation. A few years ago, a new class of treatments arrived – poly-ADP-ribose polymerase inhibitors, or PARP inhibitors.
As a class of oncology medicines, PARP inhibitors are currently approved for women with recurrent ovarian cancer, as a maintenance treatment, if their disease has responded to platinum-based chemotherapy.[iii] Select PARP inhibitors are also available for a smaller group of women whose disease has a certain mutation, both as a first-line maintenance treatment after response on platinum-based chemotherapy and as a treatment for women whose disease has recurred multiple times.[iv] Given that about 70 percent of patients diagnosed with ovarian cancer will have a recurrence, it is important that women have more treatment options throughout the course of their disease.[v]
A newer class of treatment
PARP is a family of proteins that are involved in many functions in a cell, including DNA repair, gene expression, cell cycle control, and energy metabolism.[vi]
In healthy cells, DNA damage occurs and is repaired by proteins, such as PARP. This helps the cells continue to function. This damage can be spontaneous or the result of environmental factors like radiation or some chemicals.[vi] ,[vii],[viii] In cancer cells, PARP does the same thing: even though the cells are cancerous, PARP still helps the cancer cells repair themselves so they can continue to function.[vi],[ix],[x], [xi]
PARP inhibitors are a targeted therapy that block the PARP protein, which means the damaged DNA can’t be repaired in the cancer cell, so the DNA accumulates more and more damage, turning from single-strand breaks to double-strand breaks. This accumulation can lead to the death of the cancer cell.[v],[vi]
The latest industry-wide research on PARP inhibitors is investigating their potential for women living with ovarian cancer at all stages of their treatment.[xii] These important insights will help to determine whether a broader group of patients could benefit from this approach. At GSK, we are committed to increasing treatment options for women living with ovarian cancer.
[i]Ovarian Cancer Statistics. World Cancer Research Fund International. https://www.wcrf.org/dietandcancer/cancer-trends/ovarian-cancer-statistics. Accessed September 2019.
[ii]Ovarian, Fallopian Tube, and Peritoneal Cancer: Statistics. Cancer.net. https://www.cancer.net/cancer-types/ovarian-fallopian-tube-and-peritoneal-cancer/statistics. Accessed August 2019.
[iii]Ovarian Cancer. National Organization for Rare Disorders. https://rarediseases.org/rare-diseases/ovarian-cancer/. Accessed September 2019.
[iv]Jiang X, Li W, Li X, Bai H, Zhang Z. Current status and future prospects of PARP inhibitor clinical trials in ovarian cancer. Cancer Manag Res. 2019;11:4371–4390. Published 2019 May 10. doi:10.2147/CMAR.S200524
[v]Recurrence. Ocrahope.org. https://ocrahope.org/patients/about-ovarian-cancer/recurrence/. Accessed September 2019
[vi]NCI Drug Dictionary – PARP. National Cancer Institute. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/parp. Accessed September 2019.
[vii]Davar D, Beumer JH, Hamieh L, Tawbi H. Role of PARP inhibitors in cancer biology and therapy. Curr Med Chem. 2012;19(23):3907-3921.
[viii]Cooper GM. DNA repair. In: The Cell. 2nd ed. Sunderland, MA: Sinauer Associates; 2000. https://www.ncbi.nlm.nih.gov/books/NBK9900/. Accessed September 2019.
[ix]Jubin T, Kadam A, Jariwala M, et al. The PARP family: insights into functional aspects of poly(ADP-ribose) polymerase-1 in cell growth and survival. Cell Prolif. 2016;49(4):421-437.
[x]Lodish H, ed. Tumor cells and the onset of cancer. In: Molecular CelI Biology. 4th ed. New York, NY: Freeman: 2002. https://www.ncbi.nlm.nih.gov/books/. Accessed September 2019.
[xi]Ciccia A, Elledge SJ. The DNA damage response: making it safe to play with knives. Mol Cell. 2010:40(2):179-204.
[xii]Jiang X, Li W, Li X, Bai H, Zhang Z. Current status and future prospects of PARP inhibitor clinical trials in ovarian cancer. Cancer Manag Res. 2019;11:4371–4390. Published 2019 May 10. doi:10.2147/CMAR.S200524