posted on 2023-08-15, 08:21authored bySanna Pikkusaari, Manuela Tumiati, Anni Virtanen, Jaana Oikkonen, Yilin Li, Fernando Perez-Villatoro, Taru Muranen, Matilda Salko, Kaisa Huhtinen, Anna Kanerva, Heidi Koskela, Johanna Tapper, Riitta Koivisto-Korander, Titta Joutsiniemi, Ulla-Maija Haltia, Heini Lassus, Sampsa Hautaniemi, Anniina Färkkilä, Johanna Hynninen, Sakari Hietanen, Olli Carpén, Liisa Kauppi
<p>Low fHR scores correlate with better primary therapy response and with longer PFI. <b>A,</b> For patients with chemo-naïve samples, the median of fHR scores is lower in CR and PR groups compared with SD/PD (Mann–Whitney test, two-tailed). Only patients with fHRP tumors had SD/PD after primary therapy. <b>B,</b> The median of fHR scores was lower in CR and PR groups compared with SD/PD also for patients with fHR score from IDS/NACT-treated sample (Mann–Whitney test, two-tailed). <b>C,</b> Proportions of CR, PR, and SD/PD are significantly different between fHRP and fHRD groups (Fisher exact test, two-tailed). <b>D</b> and <b>E,</b> PFI and OS significantly correlate with lower fHR scores (linear regression). <b>F,</b> Multivariate hazard ratio analysis for PFI with fHR status and prognostic clinical parameters. The fHRD status and success of cytoreduction significantly correlated with longer PFI (Cox proportional hazards regression). Blue = fHRD, red = fHRP.</p>
Deficiency in homologous recombination (HR) repair of DNA damage is characteristic of many high-grade serous ovarian cancers (HGSC). It is imperative to identify patients with homologous recombination–deficient (HRD) tumors as they are most likely to benefit from platinum-based chemotherapy and PARP inhibitors (PARPi). Existing methods measure historical, not necessarily current HRD and/or require high tumor cell content, which is not achievable for many patients. We set out to develop a clinically feasible assay for identifying functionally HRD tumors that can predict clinical outcomes.
We quantified RAD51, a key HR protein, in immunostained formalin-fixed, paraffin-embedded (FFPE) tumor samples obtained from chemotherapy-naïve and neoadjuvant chemotherapy (NACT)-treated HGSC patients. We defined cutoffs for functional HRD separately for these sample types, classified the patients accordingly as HRD or HR-proficient, and analyzed correlations with clinical outcomes. From the same specimens, genomics-based HRD estimates (HR gene mutations, genomic signatures, and genomic scars) were also determined, and compared with functional HR (fHR) status.
fHR status significantly predicted several clinical outcomes, including progression-free survival (PFS) and overall survival (OS), when determined from chemo-naïve (PFS, P < 0.0001; OS, P < 0.0001) as well as NACT-treated (PFS, P < 0.0001; OS, P = 0.0033) tumor specimens. The fHR test also identified as HRD those PARPi-at-recurrence–treated patients with longer OS (P = 0.0188).
We developed an fHR assay performed on routine FFPE specimens, obtained from either chemo-naïve or NACT-treated HGSC patients, that can significantly predict real-world platinum-based chemotherapy and PARPi response.See related commentary by Garg and Oza, p. 2957