Clinical analysis of pathologic complete responders in advanced-stage ovarian cancer

OBJECTIVE

To determine the clinical characteristics of patients who attained pathologic complete response (pCR) after neoadjuvant chemotherapy (NACT) and to identify specific predictive or prognostic factors associated with pCR.

METHODS

Two distinct populations of patients who underwent NACT followed by interval tumor reductive surgery (TRS) were used in this retrospective study. The first contained 472 patients from a single institution. The second contained only pCR patients (67); those identified from population one, plus 44 obtained through collaborative institutions. Cox analysis and log-rank tests were performed to assess associations between clinical characteristics and pCR outcome, recurrence-free survival (RFS), and overall survival (OS).

RESULTS

The median RFS and OS in our pCR-only population was 24.2 and 80.8 months, respectively, with a median follow-up time of 32.4 months. In our single institution population, 23 patients attained pCR (4.9%) and had longer RFS compared to non-pCR patients with viable microscopic, optimal, or suboptimal residual disease (24.3 vs. 12.1 vs. 11.6 vs. 9.6 months, p = 0.025, 0.012, 0.008, respectively), and longer OS compared to those with optimal or suboptimal residual disease (54.5 vs. 29.4 vs. 25.7 months, p = 0.027, 0.007, respectively). Patients were more than three-fold likely to attain pCR if their CA125 value was normal at the time of surgery (OR 3.54, 95% CI: 1.14-11.05, p = 0.029).

CONCLUSIONS

Women with pCR after NACT have significantly longer RFS compared to those with residual viable tumor at the time of interval tumor-reductive surgery, and CA125 is plausible biomarker for identifying these extreme responders preoperatively.

Endometrial cancer

Although endometrial cancer management remains challenging, a deeper understanding of the genetic diversity as well as the drivers of the various pathogenic states of this disease has led to development of divergent management approaches in an effort to improve therapeutic precision in this complex malignancy. This comprehensive review provides an update on the epidemiology, pathophysiology, diagnosis and molecular classification, recent advancements in disease management, as well as important patient quality-of-life considerations and emerging developments in the rapidly evolving therapeutic landscape of endometrial cancers.

Phase Ib Dose Expansion and Translational Analyses of Olaparib in Combination with Capivasertib in Recurrent Endometrial, Triple-Negative Breast, and Ovarian Cancer

PURPOSE

On the basis of strong preclinical rationale, we sought to confirm recommended phase II dose (RP2D) for olaparib, a PARP inhibitor, combined with the AKT inhibitor capivasertib and assess molecular markers of response and resistance.

PATIENTS AND METHODS

We performed a safety lead-in followed by expansion in endometrial, triple-negative breast, ovarian, fallopian tube, or peritoneal cancer. Olaparib 300 mg orally twice daily and capivasertib orally twice daily on a 4-day on 3-day off schedule was evaluated. Two dose levels (DL) of capivasertib were planned: 400 mg (DL1) and 320 mg (DL-1). Patients underwent biopsies at baseline and 28 days.

RESULTS

A total of 38 patients were enrolled. Seven (18%) had germline BRCA1/2 mutations. The first 2 patients on DL1 experienced dose-limiting toxicities (DLT) of diarrhea and vomiting. No DLTs were observed on DL-1 (n = 6); therefore, DL1 was reexplored (n = 6) with no DLTs, confirming DL1 as RP2D. Most common treatment-related grade 3/4 adverse events were anemia (23.7%) and leukopenia (10.5%). Of 32 evaluable subjects, 6 (19%) had partial response (PR); PR rate was 44.4% in endometrial cancer. Seven (22%) additional patients had stable disease greater than 4 months. Tumor analysis demonstrated strong correlations between response and immune activity, cell-cycle alterations, and DNA damage response. Therapy resistance was associated with receptor tyrosine kinase and RAS-MAPK pathway activity, metabolism, and epigenetics.

CONCLUSIONS

The combination of olaparib and capivasertib is associated to no serious adverse events and demonstrates durable activity in ovarian, endometrial, and breast cancers, with promising responses in endometrial cancer. Importantly, tumor samples acquired pre- and on-therapy can help predict patient benefit.

ATHENA (GOG-3020/ENGOT-ov45): a randomized, phase III trial to evaluate rucaparib as monotherapy (ATHENA-MONO) and rucaparib in combination with nivolumab (ATHENA-COMBO) as maintenance treatment following frontline platinum-based chemotherapy in ovarian cancer

Background

The optimal treatment strategy for women with newly diagnosed ovarian cancer has yet to be determined. Poly(ADP-ribose) polymerase (PARP) inhibitors have demonstrated substantial improvement in progression-free survival as monotherapy maintenance treatment in the frontline setting versus active surveillance. Furthermore, preclinical and early clinical studies have shown that PARP inhibitors and immune checkpoint inhibitors have synergistic antitumor activity and may provide an additional therapeutic option for patients in this population.

Primary Objectives

In women with newly diagnosed ovarian, fallopian tube, or peritoneal cancer, we wish to assess the efficacy of frontline maintenance treatment with the PARP inhibitor rucaparib versus placebo following response to platinum-based chemotherapy (ATHENA–MONO), and to assess the combination of rucaparib plus nivolumab (a programmed death receptor 1 (PD-1)–blocking monoclonal antibody) versus rucaparib alone (ATHENA–COMBO).

Study Hypothesis

(1) Maintenance therapy with rucaparib monotherapy may extend progression-free survival following standard treatment for ovarian cancer in the frontline setting. (2) The combination of nivolumab plus rucaparib may extend progression-free survival following standard treatment for ovarian cancer in the frontline setting compared with rucaparib alone.

Trial Design

ATHENA is an international, randomized, double-blind, phase III trial consisting of two independent comparisons (ATHENA–MONO and ATHENA–COMBO) in patients with newly diagnosed platinum-sensitive ovarian cancer. Patients are randomized 4:4:1:1 to the following: oral rucaparib+ intravenous nivolumab (arm A); oral rucaparib + intravenous placebo (arm B); oral placebo+ intravenous nivolumab (arm C); and oral placebo + intravenous placebo (arm D). The starting dose of rucaparib is 600 mg orally twice a day and nivolumab 480 mg intravenously every 4 weeks. ATHENA–MONO compares arm B with arm D to evaluate rucaparib monotherapy versus placebo, and ATHENA–COMBO evaluates arm A versus arm B to investigate the effects of rucaparib and nivolumab in combination versus rucaparib monotherapy. ATHENA–MONO and ATHENA–COMBO share a common treatment arm (arm B) but each comparison is independently powered.

Major Inclusion/Exclusion Criteria

Patients ≥18 years of age with newly diagnosed advanced, high-grade epithelial ovarian, primary peritoneal, or fallopian tube cancer who have achieved a response after completion of cytoreductive surgery and initial platinum-based chemotherapy are enrolled. No other prior treatment for ovarian cancer, other than the frontline platinum regimen, is permitted.

Primary Endpoint

The primary endpoint is investigator-assessed progression-free survival by Response Evaluation Criteria in Solid Tumors v1.1.

Sample Size

Approximately 1000 patients have been enrolled and randomized.

Estimated Dates for Completing Accrual and Presenting Results

The trial completed accrual in 2020. While dependent on event rates, primary results of ATHENA–MONO are anticipated in early 2022 and results of ATHENA–COMBO are anticipated to mature at a later date.

Trial Registration

This trial is registered at clinicaltrials.gov (NCT03522246).

Rational Combination of CRM1 Inhibitor Selinexor and Olaparib Shows Synergy in Ovarian Cancer Cell Lines and Mouse Models

CRM1 inhibitors have demonstrated antitumor effects in ovarian and other cancers; however, rational combinations are largely unexplored. We performed a high-throughput drug library screen to identify drugs that might combine well with selinexor in ovarian cancer. Next, we tested the combination of selinexor with the top hit from the drug screen in vitro and in vivo Finally, we assessed for mechanisms underlying the identified synergy using reverse phase protein arrays (RPPA). The drug library screen assessing 688 drugs identified olaparib (a PARP inhibitor) as the most synergistic combination with selinexor. Synergy was further demonstrated by MTT assays. In the A2780luc ip1 mouse model, the combination of selinexor and olaparib yielded significantly lower tumor weight and fewer tumor nodules compared with the control group (P < 0.04 and P < 0.03). In the OVCAR5 mouse model, the combination yielded significantly fewer nodules (P = 0.006) and markedly lower tumor weight compared with the control group (P = 0.059). RPPA analysis indicated decreased expression of DNA damage repair proteins and increased expression of tumor suppressor proteins in the combination treatment group. Collectively, our preclinical findings indicate that combination with selinexor to expand the utility and efficacy of PARP inhibitors in ovarian cancer warrants further exploration.

Immune microenvironment composition in high-grade serous ovarian cancers based on BRCA mutational status

PURPOSE

An in-depth analysis of the tumor microenvironment of ovarian cancer is needed. The purpose of this study was to elucidate the architecture of the immune microenvironment of high-grade serous ovarian cancers (HGSCs) with or without BRCA1 and BRCA2 mutations.

METHODS

A cohort of highly annotated HGSC patients with known germline BRCA1 and BRCA2 status was selected, and pretreatment tumor tissue specimens were analyzed with a multiplexed staining technique aimed at detecting lymphocytes, macrophages, and fibroblasts in the whole tumor area and in specific regions including epithelium, stroma, and perivascular areas.

RESULTS

BRCA1- or BRCA2-mutated tumors showed a more immunogenic microenvironment, characterized by a higher abundance of CD8⁺ and PD-L1⁺ cells, than did tumors with wild-type BRCA1 and BRCA2. High numbers of PD-L1⁺ and PD-L1⁺CD8⁺ cells were prognostic for event-free survival (hazard ratio [HR]: 0.41, 95% CI 0.21-0.79, p = 0.008 and HR 0.49, 95% CI 0.26-0.91, p = 0.025, respectively), as were high numbers of epithelial PD-L1⁺ and FAP⁺PD-L1⁺ cells (HR 0.52, 95% CI 0.28-0.96, p = 0.037 and HR 0.27, 95% CI 0.08-0.87, p = 0.029) and CD8⁺ cells (HR 0.51, 95% CI 0.28-0.93, p = 0.027).

CONCLUSIONS

This study reveals substantial differences between the immune microenvironment composition of germline BRCA-mutated and BRCA wild-type HGSC.

Risk factors for progression or death after first-line platinum-based chemotherapy in real-world patients in the USA with ovarian cancer from 2011 to 2018

Aim: Patient chart data from the USA during the period of January 2011 through October 2018 were used to assess risk factors for progression in advanced ovarian cancer after response to first-line platinum-based chemotherapy. Patients & methods: Patients with stage III/IV ovarian cancer who completed first-line platinum-based chemotherapy after primary or interval debulking surgery were identified from the Flatiron Health database. Cox proportional hazards modeling was used to assess associations between baseline factors and time to next treatment (TTNT) or overall survival (OS). Results: Patients at stage IV or who received interval debulking surgery had shorter TTNT and OS than patients at stage III or who received primary debulking surgery, respectively. OS was worse in patients with residual disease and in BRCA wild-type. Conclusion: Multiple factors were associated with shorter TTNT or OS in this retrospective real-world analysis.

Movement of Poly-ADP Ribose (PARP) Inhibition into Frontline Treatment of Ovarian Cancer

The use of poly (ADP-ribose) polymerase (PARP) inhibitors in the front-line management of advanced ovarian cancer has recently emerged as an exciting strategy with the potential to improve outcomes for patients with advanced ovarian cancer. In this article, we review the results of four recently published Phase III randomised controlled trials evaluating the use of PARP inhibitors in the primary treatment of ovarian cancer (SOLO1, PRIMA, PAOLA-1, and VELIA). Collectively, the studies suggest that PARP maintenance in the upfront setting is most beneficial among patients with BRCA-associated ovarian cancers (hazard ratios range from 0.31 to 0.44), followed by patients with tumours that harbour homologous recombination deficiencies (hazard ratios range from 0.33 to 0.57). All three studies that included an all-comer population were able to demonstrate benefit of PARP inhibitors, regardless of biomarker status. The FDA has approved olaparib for front-line maintenance therapy among patients with BRCA-associated ovarian cancers, and niraparib for all patients, regardless of biomarker status. In determining which patients should be offered front-line maintenance PARP inhibitors, and which agent to use, there are multiple factors to consider, including FDA indication, dosing preference, toxicity, risks versus benefits for each patient population, and cost. There are ongoing studies further exploring the front-line use of PARP inhibitors, including the potential downstream effects of PARP-inhibitor resistance in the recurrent setting, combining PARP-inhibitors with other anti-angiogenic drugs, immunotherapeutic agents, and inhibitors of pathways implicated in PARP inhibitor resistance.

Factors associated with response to neoadjuvant chemotherapy in advanced stage ovarian cancer

OBJECTIVES

To evaluate the factors associated with response to neoadjuvant chemotherapy (NACT) and the ability to undergo interval tumor reductive surgery (iTRS) in patients with advanced ovarian cancer.

METHODS

We performed a retrospective review from April 2013 to March 2019 of patients with advanced stage ovarian cancer triaged to NACT based on our standard triage algorithm. Clinicopathologic and treatment data were analyzed for factors associated with response to NACT, outcomes at iTRS, and their impact on progression-free survival (PFS).

RESULTS

562 patients met inclusion criteria and triaged to NACT following laparoscopy (n = 132) or without laparoscopy (n = 430). 413 patients underwent iTRS (74%). Factors that correlated with a patient reaching iTRS included increasing age (p < 0.001), higher Charlson comorbidity index (p < 0.001), ECOG status 2 or 3 (<0.001), and laparoscopic assessment (<0.001). Patients with CA-125 ≤ 35 U/mL at iTRS had higher rates of complete gross resection (88% vs. 65%, p < 0.001) and improved PFS (16.8 vs. 12.7 months, p < 0.001). Patients receiving dose-dense paclitaxel (76% vs. 60%, p = 0.004) and CA-125 ≤ 35 U/mL at iTRS (85% vs. 66%, p < 0.001) had higher rates of complete radiographic response. On multivariate analysis, germline BRCA 1/2 mutation (p = 0.001), iTRS vs. no surgery (R0, p < 0.001; ≤1 cm, p < 0.001; >1 cm, p < 0.001), dose-dense chemotherapy (p = 0.01), and CA-125 ≤ 35 U/mL at iTRS (p = 0.001) were independent significant factors affecting PFS.

CONCLUSIONS

Normalization of CA-125 at the time of iTRS following NACT may serve as a surrogate marker for prognosis in this high-risk population. Our NACT cohort experienced improved response rates and PFS with dose-dense therapy compared to conventional dosing.

Rationale for combination PARP inhibitor and antiangiogenic treatment in advanced epithelial ovarian cancer: A review

Inhibitors of poly(ADP-ribose) polymerase (PARP) and angiogenesis have demonstrated single-agent activity in women with advanced ovarian cancer. Recent studies have aimed to establish whether combination therapy can augment the response seen with PARP inhibitors or antiangiogenic agents alone. This review provides an overview of PARP inhibitors and antiangiogenics as monotherapy in women with advanced ovarian cancer, explores potential mechanisms of action of PARP inhibitor and antiangiogenic combination treatments, reviews efficacy and safety data from trials evaluating this combination, and outlines ongoing and future trials evaluating this combination, discussing these in the context of the current and future treatment landscape for women with advanced ovarian cancer. Sentinel studies evaluating PARP inhibitor (n = 8), antiangiogenic (n = 4), and combination (n = 7) therapy were identified in women with newly diagnosed (n = 7) and recurrent (n = 12) ovarian cancer. PARP inhibitors included olaparib (n = 9), niraparib (n = 4), rucaparib (n = 1), and veliparib (n = 1). Antiangiogenic agents included bevacizumab (n = 7) and cediranib (n = 4). PARP inhibitors combined with antiangiogenics demonstrated efficacy based on objective response rates and progression-free survival (PFS) in the relapsed disease setting. Maintenance therapy with the PARP inhibitor, olaparib, plus antiangiogenic therapy offered a significant PFS benefit versus the antiangiogenic alone in women with newly diagnosed advanced ovarian cancer who tested positive for homologous recombination deficiency. Combination therapy was tolerated, with no new safety signals reported compared with monotherapy trials. PARP inhibitors and antiangiogenics have changed the landscape of ovarian cancer treatment. The PARP inhibitor plus antiangiogenic combination is a novel treatment option that appears promising in the first-line advanced and recurrent ovarian cancer settings, although the role of this combination in recurrent disease requires further elucidation. Defining which patients are candidates for monotherapy or combination therapy is critical, taking into consideration safety profiles of therapies alone or in combination, and how these treatments should be sequenced in clinical practice.

Toxicity and efficacy of the combination of pembrolizumab with recommended or reduced starting doses of lenvatinib for treatment of recurrent endometrial cancer

OBJECTIVE

We reviewed our institutional data to evaluate toxicity and efficacy outcomes of pembrolizumab/lenvatinib in recurrent endometrial cancer in a "real-world" clinical setting and to compare the impact of reduced lenvatinib starting dose on outcomes.

METHODS

Retrospectively, we reviewed toxicity, treatment responses, and survival outcomes of patients with recurrent endometrial cancer who received ≥1 cycle of pembrolizumab/lenvatinib. We compared subgroups based on lenvatinib starting dose (recommended [20 mg] vs reduced [<20 mg]) and histologic type.

RESULTS

We analyzed 70 patients (recommended dose cohort, n = 16; reduced dose cohort, n = 54). The most common starting dose was 14 mg daily. Compared to the reduced dose cohort, the recommended dose cohort had a significantly higher mean number of lenvatinib dose reductions due to side effects (1.1 vs. 0.4; p = 0.003) and significantly shorter median time to treatment toxicity (1.3 vs. 3.7 days; p = 0.0001). Response rates did not differ significantly between the recommended and reduced dose cohorts (28.6% vs. 38.3%, respectively; p = 0.752). Two patients, both in the reduced dose cohort, had complete responses. Patients with carcinosarcoma histology had response and clinical benefit rates of 25% (3 of 12) and 58.3% (7 of 12), respectively. There were no differences between the 2 dose cohorts with respect to progression-free (p = 0.245) or overall survival (p = 0.858).

CONCLUSION

In clinical practice, a lower starting dose of lenvatinib (14 mg daily) in combination with pembrolizumab was safe and efficacious in recurrent endometrial cancer. The combination produced responses in endometrial carcinosarcomas. Larger studies are required to validate these findings.

Dasatinib, paclitaxel, and carboplatin in women with advanced-stage or recurrent endometrial cancer: A pilot clinical and translational study

PURPOSE

To evaluate the effect of dasatinib therapy on EphA2 signaling in cancers of women with measurable (biopsy amenable) advanced-stage, chemo-naïve primary or recurrent endometrial cancer. Preliminary efficacy was also assessed.

PATIENTS AND METHODS

We performed a pilot study of single-agent dasatinib lead-in, followed by triplet dasatinib, paclitaxel, and carboplatin. We measured the downstream effectors of EphA2 signaling in pre- and post-dasatinib treatment biopsy tissue samples; we also determined the severity of adverse events and patients' progression-free survival and overall survival durations.

RESULTS

Eighteen patients were recruited and given dasatinib (150 mg orally daily for 14 days), followed by paclitaxel, carboplatin and dasatinib (daily) for six cycles (21-day cycles). Seventeen patients were evaluable for toxicity and 11 patients for response. A reverse phase protein array and proximity ligation assay revealed that CRAF/BRAF dimerization, caveolin-1 level, and Notch pathway signaling were predictive of response and resistance to dasatinib. Overall, the objective response rate was 45% (95% CI: 17%-77%), with median progression-free survival duration of 10.5 months and median overall survival duration of 30.4 months. The most common grade 3 or 4 adverse events were neutropenia (76%), thrombocytopenia (53%), anemia (53%), and fatigue (12%).

CONCLUSIONS

Caveolin-1 expression, in combination with CRAF/BRAF heterodimerization, is associated with resistance to EphA2 targeting by dasatinib. The triplet combination showed interesting clinical activity in endometrial cancer with acceptable toxicity. Pretreatment with dasatinib may accentuate combination therapy toxicity.

A Modified 2 Tier Chemotherapy Response Score (CRS) and Other Histopathologic Features for Predicting Outcomes of Patients with Advanced Extrauterine High-Grade Serous Carcinoma after Neoadjuvant Chemotherapy

Background: The impact of chemotherapy response score (CRS) on prognosis has varied among studies. We addressed the prognostic significance of CRS and the prognostic value of previously undescribed histologic features using a cohort of 245 patients. Methods: Retrospective study in patients with advanced extrauterine high-grade serous carcinomas treated with neoadjuvant chemotherapy followed by interval tumor reductive surgery from 1990 to 2018 in our hospital. Gynecologic pathologists assessed tumor CRS and other histologic features. Clinical information was collected, and multivariate analyses were conducted. Results: A modified 2 tier CRS (CRS 1/2 versus CRS 3) was significantly associated, independent of scoring site (omental versus adnexal), with overall survival (OS) (omentum, p = 0.018; adnexa, p = 0.042; entire cohort, p = 0.002) and progression-free survival (PFS) (p = 0.021, p = 0.035, and p = 0.001, respectively). On multivariate survival analysis, 2 tier CRS, oncocytic change, inflammation, and desmoplasia were significant for OS (p = 0.034, p = 0.020, p = 0.007, and p = 0.010, respectively). Likewise, 2 tier CRS, inflammation, and desmoplasia were significant for PFS (p = 0.012, p = 0.003, p = 0.011, respectively). Conclusions: The modified 2 tier CRS was significantly associated with survival, independent of scoring site. Additional histologic features including oncocytic change, inflammation, and desmoplasia can also predict patient outcomes.

Current and future landscape of poly (ADP-ribose) polymerase inhibition resistance

PURPOSE OF REVIEW

To highlight relevant strategies to overcome poly(ADP-ribose) polymerase (PARP) inhibitor resistance and present key clinical trials.

RECENT FINDINGS

The use of PARP inhibition (PARPi) for frontline maintenance offers substantial clinical benefit in patients with homologous recombination-deficient tumors. However, expanding PARPi from recurrent therapy to frontline maintenance may potentially result in more PARPi resistant tumors earlier in the treatment continuum and data for the use of PARPi after PARPi remain limited. Clinical evidence demonstrates tumors may develop resistance to PARPi through demethylation of the BRCA promoter or BRCA reversion mutations. Multiple clinical trials investigating therapeutic strategies to overcome resistance, such as combinations of PARPi with antiangiogenic drugs, PI3K/AKT/mTOR, or MEK inhibitors have already been reported and more are ongoing. Furthermore, increasing the amount of DNA damage in the tumor using chemotherapy or cell cycle inhibitors such as ATM, ATR/CHK1/WEE1 is also under exploration.

SUMMARY

There is increasing clinical interest to identify options to enhance PARPi efficacy and overcome adaptive resistance. PARPi represent a class of drugs that have significantly impacted the treatment and maintenance of ovarian cancer; as the use of PARPi increases, better understanding of resistance mechanisms is essential.

Cost-effectiveness of laparoscopic disease assessment in patients with newly diagnosed advanced ovarian cancer

OBJECTIVE

To determine if laparoscopy is a cost-effective way to assess disease resectability in patients with newly diagnosed advanced ovarian cancer.

METHODS

A cost-effectiveness analysis from a health care payer perspective was performed comparing two strategies: (1) a standard evaluation strategy, where a conventional approach to treatment planning was used to assign patients to either primary cytoreduction (PCS) or neoadjuvant chemotherapy with interval cytoreduction (NACT), and (2) a laparoscopy strategy, where patients considered candidates for PCS would undergo laparoscopy to triage between PCS or NACT based on the laparoscopy-predicted likelihood of complete gross resection. A microsimulation model was developed that included diagnostic work-up, surgical and adjuvant treatment, perioperative complications, and progression-free survival (PFS). Model parameters were derived from the literature and our published data. Effectiveness was defined in quality-adjusted PFS years. Results were tested with deterministic and probabilistic sensitivity analysis (PSA). The willingness-to-pay (WTP) threshold was set at $50,000 per year of quality-adjusted PFS.

RESULTS

The laparoscopy strategy led to additional costs (average additional cost $7034) but was also more effective (average 4.1 months of additional quality-adjusted PFS). The incremental cost-effectiveness ratio (ICER) of laparoscopy was $20,376 per additional year of quality-adjusted PFS. The laparoscopy strategy remained cost-effective even as the cost added by laparoscopy increased. The benefit of laparoscopy was influenced by mitigation of serious complications and their associated costs. The laparoscopy strategy was cost-effective across a range of WTP thresholds.

CONCLUSIONS

Performing laparoscopy is a cost-effective way to improve primary treatment planning for patients with untreated advanced ovarian cancer.

Distinct T cell receptor repertoire diversity of clinically defined high-grade serous ovarian cancer treatment subgroups

In patients with high-grade serous ovarian cancer (HGSC), it is unclear which genomic features are related to complete gross resection (R0), which is typically associated with better clinical outcomes, or response to neoadjuvant chemotherapy (NACT). In this study, we evaluated T cell receptor (TCR) repertoire diversity in primary and metastatic tumor samples (n = 90) from clinically well-annotated patients with HGSC who achieved R0 or received NACT with excellent or poor response based on a laparoscopic triage algorithm. TCR sequencing followed by an integrative analysis with comprehensive multi-omics data identified higher TCR diversity (e.g., higher number of unique productive sequences and less clonal relatedness) in the R0 than NACT groups. We found enrichment of specific TCRβ genes usage, distinct mutual exclusiveness and co-occurrence pattern of TCRβ genes among the groups. We also found significantly positive correlations between clonal relatedness and neoantigens, copy number variations, and mutation load in the groups.

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Higher TCR repertoire diversity in the R0 versus neoadjuvant chemotherapy groups

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Enrichment of specific TCRβ genes usage was noted among HGSC subgroups

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Distinct mutual exclusiveness of TCRβ genes was noted among HGSC subgroups

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Positive correlations between clonal relatedness and copy number variations

Correlation of surgeon radiology assessment with laparoscopic disease site scoring in patients with advanced ovarian cancer

BACKGROUND

Radiographic triage measures in patients with new advanced ovarian cancer have yielded inconsistent results.

OBJECTIVE

To determine the correlation between surgeon radiology assessment and laparoscopic scoring by disease sites in patients with newly diagnosed advanced stage ovarian cancer.

METHODS

Fourteen gynecologic oncology surgeons from a single institution performed a blinded review of pre-operative contrast-enhanced CT imaging from patients with advanced stage ovarian cancer. Each of the patients had also undergone laparoscopic scoring assessment, between April 2013 and December 2017, to determine primary resectability using the validated Fagotti scoring method, and assigned a predictive index value score. Surgeons were asked to provide expected predictive index value scores based on their blinded review of the antecedent CT imaging. Linear mixed models were conducted to calculate the correlation between radiologic and laparoscopic score for surgeons individually, and as a group. Once the model was fit, the inter-class correlation and 95% CI were calculated.

RESULTS

Radiology review was performed on 20 patients with advanced stage ovarian cancer who underwent laparoscopic scoring assessment. Surgeon faculty rank included assistant professor (n=5), associate professor (p=4), and professor (n=5). The kappa inter-rater agreement was -0.017 (95% CI -0.023 to -0.005), indicating low inter-rater agreement between radiology review and actual laparoscopic score. The inter-class correlation in this model was 0.06 (0.02-0.21), indicating that surgeons do not score the same across all the images. When using a clinical cut-off point for the predictive index value of 8, the probability of agreement between radiology and actual laparoscopic score was 0.56 (95% CI 0.49 to 0.73). Examination of disease site sub-scales showed that the probability of agreement was as follows: peritoneum 0.57 (95% CI 0.51 to 0.62), diaphragm 0.54 (95% CI 0.48 to 0.60), mesentery 0.51 (95% CI 0.45 to 0.57), omentum 0.61 (95% CI 0.55 to 0.67), bowel 0.54 (95% CI 0.44 to 0.64), stomach 0.71 (95% CI 0.65 to 0.76), and liver 0.36 (95% CI 0.31 to 0.42). The number of laparoscopic scoring cases, tumor reductive surgery cases, or faculty rank was not significantly associated with overall or sub-scale agreement.

CONCLUSIONS

Surgeon radiology review did not correlate highly with actual laparoscopic scoring assessment findings in patients with advanced stage ovarian cancer. Our study highlights the limited accuracy of surgeon radiographic assessment to determine resectability.

Phase II study of pembrolizumab efficacy and safety in women with recurrent small cell neuroendocrine carcinoma of the lower genital tract

OBJECTIVE

To investigate the efficacy and safety of pembrolizumab in women with recurrent small cell neuroendocrine tumors of the lower genital tract.

METHODS

We conducted an open-label, investigator-initiated phase II basket trial of pembrolizumab 200 mg intravenously every 3 weeks in patients with rare tumors (ClinicalTrials.gov: NCT02721732). The trial had prespecified cohorts, including small cell malignancies of extrapulmonary origin. Eligibility criteria included disease progression during standard treatment in the 6 months before study enrollment. Patients were enrolled from February 2017 to February 2019. The primary endpoint was the proportion of patients alive without progression at 27 weeks. Response to pembrolizumab was evaluated every 9 weeks (3 cycles) with radiographic imaging.

RESULTS

Seven women with gynecologic extrapulmonary small cell carcinoma were enrolled, 6 with cervical and 1 with vulvar carcinoma. No patient was progression free at 27 weeks. At first radiologic assessment, 1 patient had stable disease, while 6 had progression. The single patient with stable disease at 6 weeks had disease progression at 14 weeks. The median progression-free interval was 2.1 months (range 0.8-3.3 months). Severe treatment-related adverse events (≥grade 3) were seen in 2 of 7 patients (29%); 1 patient had grade 3 asymptomatic elevation of serum alkaline phosphatase, and 1 had grade 3 asymptomatic elevation of serum alanine aminotransferase.

CONCLUSIONS

Pembrolizumab alone showed minimal activity in women with recurrent small cell neuroendocrine tumors of the lower genital tract. Treatment was well tolerated in the majority of study participants, and the rate of severe adverse events was low.

PARP inhibition in the ovarian cancer patient: Current approvals and future directions

Poly (ADP-ribose) polymerase (PARP) inhibitors have transformed the therapeutic management of solid tumors, particularly ovarian cancer. Initially studied in BRCA deficient tumors, the Food and Drug Administration (FDA) indications have expanded to include other homologous recombination deficient tumors as well as biomarker-wildtype tumors. They have also gained momentum not only as a treatment strategy, but as a maintenance strategy as well. While PARP inhibitors were initially ev aluated in the recurrent setting, they have now moved to frontline therapy. This review will discuss the current FDA indications of the clinically available PARP inhibitors for treatment and maintenance therapies. We will then review the recently completed and ongoing clinical trials which may inform future clinical approvals.

The role of neoadjuvant chemotherapy in the management of low-grade serous carcinoma of the ovary and peritoneum: Further evidence of relative chemoresistance

OBJECTIVE

Low-grade serous carcinoma of the ovary/peritoneum (LGSC) is relatively chemoresistant in the adjuvant, neoadjuvant, and recurrent settings. We sought to expand our prior work and evaluate response rates of women with LGSC to neoadjuvant chemotherapy (NACT) compared to women with high-grade serous carcinoma of the ovary/peritoneum (HGSC).

METHODS

Thirty-six patients with LGSC who received NACT were matched to patients with HGSC. A single radiologist re-reviewed pre- and post-NACT imaging for response using RECIST 1.1. Pre- and post-NACT CA-125 values were compared using paired t-tests. Kaplan-Meier estimates of progression free survival (PFS) and overall survival (OS) were performed.

RESULTS

All patients received neoadjuvant platinum-based regimens. LGSC patients received a median of 5 cycles (range 3-9), HGSC patients received a median of 4 cycles (range 3-9). Interval cytoreductive surgery was performed in 29/36 (81%) of LGSC and 32/36 (89%) HGSC patients. Complete cytoreduction was reported and achieved in 11/29 (38%) of LGSC patients and 24/32 (75%) of HGSC patients (p = 0.002). Median pre- and post-treatment CA-125 levels for LGSC patients were 295.5 U/mL and 144 U/mL (52% decrease) (p < 0.001). The median pre- and post-treatment CA-125 levels for HGSC patients were 767.5 and 35.6 (96% decrease) (p < 0.001). For LGSC patients, 4/36 (11%) had partial response (PR), 30/36 (83%) had stable disease (SD), and 2/36 (6%) had progressive disease (PD). In HGSC patients, 27/36 (75%) had PR, and 9/36 (25%) SD. Median PFS for LGSC patients was 18.5 months and median OS was 47.4 months.

CONCLUSIONS

This study provides further evidence of relative chemoresistance of LGSC in patients treated with NACT.

Abstract CT188: Pharmacodynamic changes by durvalumab in combination with chemotherapy in women with untreated, advanced stage ovarian cancer

Objectives: To evaluate safety and efficacy of durvalumab (D) in combination with paclitaxel (P) and carboplatin (C) in newly diagnosed, advanced-stage, high grade, non-mucinous ovarian cancer (OC). To investigate informative pharmacodynamic changes including proteome changes and immune-related pathways by treatment with immuno-oncology therapy in combination with chemotherapy. Methods: In this single arm phase II study, patients (pts) with untreated, advanced stage (III/IV) OC dispositioned to neoadjuvant chemotherapy (NACT) received D (750mg) with weekly P (80mg/m2) and C (AUC6) after baseline tissue biopsy. Matched biopsies were obtained at tumor reductive surgery (TRS) after 3 cycles. Progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan-Meier method. Reverse-phase protein arrays (RPPA) were performed on pre- and post-treatment tissues. Protein expression alteration and an enriched Reactome pathway analysis using differentially expressed proteins between pre- and post-treatments were assessed. Results: 19 pts were enrolled and 18 treated. Median age was 63 and 50% had stage III disease. No dose-limiting toxicities were observed. 94% of pts had an adverse event (AE). Most common AEs were anemia (94%), neutropenia (83%), fatigue (72%), hyperglycemia (73%), and thrombocytopenia (66%). Immune-related AEs observed included hyperthyroidism (22%), hypothyroidism (22%), diarrhea (6%), hypophysitis (6%). Eighty-three percent had optimal interval TRS, 70% had a pre-operative response by RECIST (PR=11, CR=1). At 13 months (mo) median follow up, 9 pts (50%) had disease progression and median PFS was 14.5 mo (95% CI: 9.2 - NA). Median OS was not reached; OS rate at 18 mo was 69% (95% CI 0.21 - 0.91). Fifty-five tumor specimens were available from 9 pts (31 pre- and 24 post-treatment). Thirteen significantly differentially expressed proteins among 211 proteins (adj. p&lt;0.1, log2FC≥1) were identified. One upregulated protein, XBP1 (log2FC=1.37) and 12 downregulated proteins were observed, including EMA, PAR, IGFBP2, and EVI1, at post- compared to pre-treatment. PD-L1 expression was significantly elevated post-treatment (adj. p=0.0065). Pathway analysis revealed pyruvate metabolism and citric acid (TCA) and PI3K/AKT were upregulated in post- compared to pre-treatment (p&lt;0.05, FDR&lt;1). Cell cycle, mismatch repair, DNA double-strand break ends processing, and homology-directed repair (HDR) through Homologous Recombination were downregulated in post- compared to pre-treatment samples (p&lt;0.05, FDR&lt;0.5). Conclusion: Durvalumab can be safely combined with chemotherapy in upfront OC with reasonable efficacy. Observed protein changes after treatment provide important implications for strategies combining immune agents and chemotherapy and inform biomarker development to individualize therapy based on induction exposure.

Citation Format: Shannon N. Westin, Sanghoon Lee, Li Zhao, Ying Yuan, Jimin Wu, Richard Hajek, Sara Sharafi, Larissa A. Meyer, Nicole D. Fleming, Amir Jazaeri, Robert L. Coleman, Karen H. Lu, Gordon B. Mills, Jianhua Zhang, Andrew Futreal, Anil K. Sood. Pharmacodynamic changes by durvalumab in combination with chemotherapy in women with untreated, advanced stage ovarian cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT188.

Abstract 2510: High-depth whole genome sequencing of clinically-annotated high-grade serous ovarian cancers

Background: Prior molecular characterization efforts for high-grade serous ovarian cancer (HGSOC) were restricted to those who had upfront surgical debulking with variable treatment paradigms. Thus, we sought to examine molecular and cellular differences between clinically defined groups (tumor tissues from patients who had complete gross resection (CGR) versus those who were triaged to neoadjuvant chemotherapy (NACT) and experienced either excellent or poor response.

Methods: Tumor biopsies were collected from three patient groups managed under a systematic surgical algorithm: CGR after primary surgery (R0, n=10); poor tumor response to NACT (NACT-PR, n=10); excellent tumor response to NACT (NACT-ER, n=10). Primary and multiple metastatic tumor sites per each patient were obtained pre-treatment and subjected to comprehensive omics analyses including high-pass whole-genome (WGS) and targeted deep DNA sequencing.

Results: An average of 71 nonsynonymous somatic mutations from each sample for 75 samples with high-purity tumors (≥75%) by WGS were identified from each sample for the entire cohort. Fourteen ovarian-cancer-associated genes were found mutated in our patient cohort and, as expected, the most frequently mutated gene was TP53 in both primary and metastatic sites in all three groups. TP53 nonsense mutations were exclusively identified in the NACT-ER (36.0%) and NACT-PR groups (15.4%), while in the R0 group most TP53 mutations were missense mutations (62.5%). Nonsense mutations in CSMD3 and PIK3CA were exclusively identified in both primary and metastatic sites in the NACT-PR group. The most frequent copy number variations (CNVs) in the R0 were copy number gain/loss of CSMD3 (67%) and copy number loss of NF1 (54%) and CDK12 (50%) in both primary and metastatic sites. Interestingly, copy number losses of NF1 were significantly lower in the NACT groups (18%, p=0.002), especially in the NACT-PR (8%, p=0.0004), when compared to the R0 group (54%). We also identified significant less observation of chromothripsis-like patterns, and a significantly higher level of strong-binding neoantigens in the R0 than in the NACT groups.

Conclusions: Our findings using HGSOC samples obtained from patients treated on a prospective algorithm identified distinct molecular abnormalities, and could have prognostic and therapeutic implications for patients with HGSOC.

Citation Format: Sanghoon Lee, Li Zhao, Shannon N. Westin, Nicholas W. Bateman, Amir A. Jazaeri, Nicole D. Fleming, Karen H. Lu, Robert L. Coleman, Gordon B. Mills, Jianhua Zhang, Thomas P. Conrads, George L. Maxwell, P. Andrew Futreal, Anil K. Sood. High-depth whole genome sequencing of clinically-annotated high-grade serous ovarian cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2510.