Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Nov 1;29(21):4419-4429.
doi: 10.1158/1078-0432.CCR-23-0898.

Validation of the Clinical Use of GIScar, an Academic-developed Genomic Instability Score Predicting Sensitivity to Maintenance Olaparib for Ovarian Cancer

Collaborators, Affiliations

Validation of the Clinical Use of GIScar, an Academic-developed Genomic Instability Score Predicting Sensitivity to Maintenance Olaparib for Ovarian Cancer

Raphaël Leman et al. Clin Cancer Res. .

Abstract

Purpose: The optimal application of maintenance PARP inhibitor therapy for ovarian cancer requires accessible, robust, and rapid testing of homologous recombination deficiency (HRD). However, in many countries, access to HRD testing is problematic and the failure rate is high. We developed an academic HRD test to support treatment decision-making.

Experimental design: Genomic Instability Scar (GIScar) was developed through targeted sequencing of a 127-gene panel to determine HRD status. GIScar was trained from a noninterventional study with 250 prospectively collected ovarian tumor samples. GIScar was validated on 469 DNA tumor samples from the PAOLA-1 trial evaluating maintenance olaparib for newly diagnosed ovarian cancer, and its predictive value was compared with Myriad Genetics MyChoice (MGMC).

Results: GIScar showed significant correlation with MGMC HRD classification (kappa statistics: 0.780). From PAOLA-1 samples, more HRD-positive tumors were identified by GIScar (258) than MGMC (242), with a lower proportion of inconclusive results (1% vs. 9%, respectively). The HRs for progression-free survival (PFS) with olaparib versus placebo were 0.45 [95% confidence interval (CI), 0.33-0.62] in GIScar-identified HRD-positive BRCA-mutated tumors, 0.50 (95% CI, 0.31-0.80) in HRD-positive BRCA-wild-type tumors, and 1.02 (95% CI, 0.74-1.40) in HRD-negative tumors. Tumors identified as HRD positive by GIScar but HRD negative by MGMC had better PFS with olaparib (HR, 0.23; 95% CI, 0.07-0.72).

Conclusions: GIScar is a valuable diagnostic tool, reliably detecting HRD and predicting sensitivity to olaparib for ovarian cancer. GIScar showed high analytic concordance with MGMC test and fewer inconclusive results. GIScar is easily implemented into diagnostic laboratories with a rapid turnaround.

PubMed Disclaimer

Figures

Figure 1. GIScar and the dataset used to develop the score. A, GIScar principle. B, Recruitment to the prospective collection. C, Clinical data used to validate GIScar. D, Proportion of BRCA-mutated and HRD-positive tumors according to MGMC on the prospective collection (n = 250 samples). E, Proportion of BRCA-mutated and HRD-positive tumors according to MGMC on the clinical collection (n = 469 samples).
Figure 1.
GIScar and the dataset used to develop the score. A, GIScar principle. B, Recruitment to the prospective collection. C, Clinical data used to validate GIScar. D, Proportion of BRCA-mutated and HRD-positive tumors according to MGMC on the prospective collection (n = 250 samples). E, Proportion of BRCA-mutated and HRD-positive tumors according to MGMC on the clinical collection (n = 469 samples).
Figure 2. Correlation of GIScar scores with MGMC status and BRCA mutation status (n = 250 samples). A, Distribution of tumor status according to GIScar. B, ROC curve of GIScar scores compared with MGMC status. C, Correlation between GIScar scores and MGMC scores. D, Distribution of GIScar scores among BRCA wild-type and BRCA-mutated tumors.
Figure 2.
Correlation of GIScar scores with MGMC status and BRCA mutation status (n = 250 samples). A, Distribution of tumor status according to GIScar. B, ROC curve of GIScar scores compared with MGMC status. C, Correlation between GIScar scores and MGMC scores. D, Distribution of GIScar scores among BRCA wild-type and BRCA-mutated tumors.
Figure 3. Kaplan–Meier estimates of PFS according to tumor GIScar status (n = 469). A, PFS in GIScar HRD-positive tumors with a BRCA mutation. B, PFS in GIScar HRD-positive tumors without a BRCA mutation. C, PFS in GIScar HRD-negative tumors.
Figure 3.
Kaplan–Meier estimates of PFS according to tumor GIScar status (n = 469). A, PFS in GIScar HRD-positive tumors with a BRCA mutation. B, PFS in GIScar HRD-positive tumors without a BRCA mutation. C, PFS in GIScar HRD-negative tumors.
Figure 4. Comparison of GIScar and MGMC results on the clinical data (n = 469 samples). A, Distribution of HRD-positive and HRD-negative tumors and tumors with inconclusive status according to GIScar (left) and MGMC (right). B, Correlation between GIScar score and MGMC score. C, PFS in BRCAwt tumors excluding the missing data of MGMC and GIScar (n = 275). D, PFS in tumors with discordant GIScar and MGMC results. E, PFS in tumors with GIScar HRD results but inconclusive MGMC HRD status.
Figure 4.
Comparison of GIScar and MGMC results on the clinical data (n = 469 samples). A, Distribution of HRD-positive and HRD-negative tumors and tumors with inconclusive status according to GIScar (left) and MGMC (right). B, Correlation between GIScar score and MGMC score. C, PFS in BRCAwt tumors excluding the missing data of MGMC and GIScar (n = 275). D, PFS in tumors with discordant GIScar and MGMC results. E, PFS in tumors with GIScar HRD results but inconclusive MGMC HRD status.
Figure 5. OS according to GIScar status and treatment arm (n = 469 samples). A, Tumors with a positive GIScar result. B, Tumors with a negative GIScar result.
Figure 5.
OS according to GIScar status and treatment arm (n = 469 samples). A, Tumors with a positive GIScar result. B, Tumors with a negative GIScar result.

References

    1. Moore K, Colombo N, Scambia G, Kim B-G, Oaknin A, Friedlander M, et al. Maintenance olaparib in patients with newly diagnosed advanced ovarian cancer. N Engl J Med 2018;379:2495–505. - PubMed
    1. Ray-Coquard I, Pautier P, Pignata S, Pérol D, González-Martín A, Berger R, et al. Olaparib plus bevacizumab as first-line maintenance in ovarian cancer. N Engl J Med 2019;381:2416–28. - PubMed
    1. González-Martín A, Pothuri B, Vergote I, DePont Christensen R, Graybill W, Mirza MR, et al. Niraparib in patients with newly diagnosed advanced ovarian cancer. N Engl J Med 2019;381:2391–402. - PubMed
    1. Monk BJ, Parkinson C, Lim MC, O'Malley DM, Oaknin A, Wilson MK, et al. A randomized, phase III trial to evaluate rucaparib monotherapy as maintenance treatment in patients with newly diagnosed ovarian cancer (ATHENA–MONO/GOG-3020/ENGOT-ov45). J Clin Oncol 2022;40:3952–64. - PMC - PubMed
    1. Mirza MR, Monk BJ, Herrstedt J, Oza AM, Mahner S, Redondo A, et al. Niraparib maintenance therapy in platinum-sensitive, recurrent ovarian cancer. N Engl J Med 2016;375:2154–64. - PubMed

MeSH terms