Phase 1b study of batiraxcept in combination with durvalumab in patients with platinum-resistant ovarian cancer

Combining an immune checkpoint inhibitor with batiraxcept (AVB-S6-500), an AXL inhibitor that acts via selective binding to growth arrest-specific protein 6 (GAS6), may improve anti-tumor immunity in platinum-resistant ovarian cancer (PROC). This phase 1b trial of durvalumab in combination with escalating doses of batiraxcept enrolled patients with recurrent PROC (NCT04019288). The primary objective was to determine the toxicity profile of the combination. Eleven patients were enrolled on the trial. No dose-limiting toxicities were observed, and no objective responses were noted. Median progression free survival (PFS) was 1.81 months (95% confidence interval (CI) 1.71-2.40), and median overall survival (OS) was 4.53 months (95% CI 2.10-24.74). Batiraxcept effectively reduced serum GAS6 levels at 1-h post-treatment, resulting in trough levels below the limit of detection in all cases but one. In conclusion, the combination of batiraxcept and durvalumab was safe and tolerable but did not demonstrate anti-tumor activity in a heterogenous population of patients with recurrent PROC.

Randomized phase 2 trial of tremelimumab and durvalumab in combination versus sequentially in recurrent platinum-resistant ovarian cancer

BACKGROUND

Single-agent immune checkpoint inhibitors (ICIs) have demonstrated limited responses in recurrent ovarian cancer; however, 30%-40% of patients achieve stable disease. The primary objective was to estimate progression-free survival (PFS) after sequential versus combination cytotoxic T-lymphocyte antigen 4 and programmed death ligand 1 ICIs in patients with platinum-resistant high-grade serous ovarian cancer (HGSOC).

METHODS

Patients were randomized to a sequential arm (tremelimumab followed by durvalumab on progression) or a combination arm (tremelimumab plus durvalumab, followed by durvalumab) via a Bayesian adaptive design that made it more likely for patients to be randomized to the more effective arm. The primary end point was immune-related PFS (irPFS).

RESULTS

Sixty-one subjects were randomized to sequential (n = 38) or combination therapy (n = 23). Thirteen patients (34.2%) in the sequential arm received durvalumab. There was no difference in PFS in the sequential arm (1.84 months; 95% CI, 1.77-2.17 months) compared with the combination arm (1.87 months; 95% CI, 1.77-2.43 months) (p = .402). In the sequential arm, no responses were observed, although 12 patients (31.6%) demonstrated stable disease. In the combination arm, two patients (8.7%) had partial response, whereas one patient (4.4%) had stable disease. Adverse events were consistent with those previously reported for ICIs. Patient-reported outcomes were similar in both arms.

CONCLUSIONS

There was no difference in irPFS for combination tremelimumab plus durvalumab compared to tremelimumab alone (administered as part of a sequential treatment strategy) in a heavily pretreated population of patients with platinum-resistant HGSOC. Response rates were comparable to prior reports, although the combination regimen did not add significant benefit, as has been previously described.

Pembrolizumab plus Chemotherapy in Advanced Endometrial Cancer

BACKGROUND

Standard first-line chemotherapy for endometrial cancer is paclitaxel plus carboplatin. The benefit of adding pembrolizumab to chemotherapy remains unclear.

METHODS

In this double-blind, placebo-controlled, randomized, phase 3 trial, we assigned 816 patients with measurable disease (stage III or IVA) or stage IVB or recurrent endometrial cancer in a 1:1 ratio to receive pembrolizumab or placebo along with combination therapy with paclitaxel plus carboplatin. The administration of pembrolizumab or placebo was planned in 6 cycles every 3 weeks, followed by up to 14 maintenance cycles every 6 weeks. The patients were stratified into two cohorts according to whether they had mismatch repair-deficient (dMMR) or mismatch repair-proficient (pMMR) disease. Previous adjuvant chemotherapy was permitted if the treatment-free interval was at least 12 months. The primary outcome was progression-free survival in the two cohorts. Interim analyses were scheduled to be triggered after the occurrence of at least 84 events of death or progression in the dMMR cohort and at least 196 events in the pMMR cohort.

RESULTS

In the 12-month analysis, Kaplan-Meier estimates of progression-free survival in the dMMR cohort were 74% in the pembrolizumab group and 38% in the placebo group (hazard ratio for progression or death, 0.30; 95% confidence interval [CI], 0.19 to 0.48; P<0.001), a 70% difference in relative risk. In the pMMR cohort, median progression-free survival was 13.1 months with pembrolizumab and 8.7 months with placebo (hazard ratio, 0.54; 95% CI, 0.41 to 0.71; P<0.001). Adverse events were as expected for pembrolizumab and combination chemotherapy.

CONCLUSIONS

In patients with advanced or recurrent endometrial cancer, the addition of pembrolizumab to standard chemotherapy resulted in significantly longer progression-free survival than with chemotherapy alone. (Funded by the National Cancer Institute and others; NRG-GY018 ClinicalTrials.gov number, NCT03914612.).

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.

Abstract 3267: Identification of a novel biomarker response in a prospective clinical trial of immune checkpoint blockade in recurrent ovarian carcinoma

The role of immune checkpoint inhibitors (ICPIs) in ovarian cancer continues to be refined. The presence of intratumoral T cells in ovarian tumors correlates with improved survival and progression, suggesting that immune modulation, such as by ICPIs, may be beneficial. However, a better understanding of the immune effects following ICPI use, particularly in those with a long progression free survival, is needed. Thus, we used imaging mass cytometry (IMC) to compare the tumor immune landscape of patients with ovarian cancer before and after a CTLA4 immune checkpoint inhibitor treatment to determine the association between alterations in immune landscapes and progression free survival.

Fine needle biopsies were obtained from 8 patients with recurrent platinum-resistant ovarian carcinoma enrolled in a phase 2 randomized trial evaluating the efficacy of Tremelimumab and Durvalumab (CTLA4 and PDL1 checkpoint inhibitors, respectively) in recurrent ovarian cancer treatment. Each patient had a pre-treatment biopsy and on-treatment biopsy after 3 cycles of CTLA4 inhibitor therapy. Progression free time (PFS) was recorded with 3 patients with a long PFS (&gt;180 days) and 5 with short PFS (&lt;60 days).

Formalin fixed paraffin embedded (FFPE) tissue sections were stained for IMC analysis via Fluidigm protocol with 34 metal-tagged antibodies to detect various cell and immune related markers. The IMC data was obtained using the Fluidigm Helios CyTOF instrument and Hyperion Imaging System laser ablation module. A novel image informatics pipeline through Matlab was used to assess the image intensity of each marker and cell location.

Using the developed image informatics pipeline, cell types and locations were analyzed for 16 samples from 8 patients. In all patients, mean CD8+ T cell densities had an increased trend in on-treatment vs pre-treatment samples (205.6 v 129.9 cells/mm2, p=0.086). An analysis of cell location found that in all patients on-treatment, the mean number of CD8+ T cells adjacent to M2 macrophages increased significantly (0.09 v. 0.17 cells, p = 0.0460) as well as the mean number of CD8+ T cells adjacent to B7H4+ tumor cells (0.035 v. 0.01 cells, p = 0.046). Furthermore, patients with a long PFS had a significantly higher number of CD8+ cells neighboring B cells on-treatment than short PFS (0.12 v. 0.27 cells, p=0.028).

Using IMC and novel image informatics pipeline, we found that patients with recurrent ovarian cancer treated with Tremelimumab with a long PFS mounted a significant immune response compared to patients with a short PFS, with a higher number of CD8+ T cells neighboring B cells after treatment. For all patients, the immune landscape altered after treatment. To our knowledge, this is the first known use of IMC to demonstrate immune response in ovarian cancer following ICPI therapy. Overall, IMC and image informatics pipeline are robust tools that simultaneously analyze multiple biomarkers and spatial location of cells to better assess the tumor immune microenvironment and cellular interactions.

Citation Format: Han Cun, Emily M. Hinchcliff, Ying Zhu, Sammy Ferri-Borgogno, Rita Cheng, Jared K. Burks, Stephen T. Wong, Amir A. Jazaeri, Samuel C. Mok. Identification of a novel biomarker response in a prospective clinical trial of immune checkpoint blockade in recurrent ovarian carcinoma [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 3267.

Disparities in gynecologic cancer genetics evaluation

An estimated 2-5% of endometrial cancers and 15-20% of high-grade, non-mucinous epithelial ovarian cancers have an underlying hereditary cause. Appropriate risk assessment, genetic counseling, and germline genetic testing for cancer predisposition genes in both gynecologic cancer patients and their at-risk relatives is essential for effective delivery of tailored cancer treatment and cancer prevention. However, significant disparities exist within medically underserved and minority populations in the United States regarding awareness of, access to, and use of genetic services. The objectives of this review are to summarize the literature on genetic counseling and genetic testing of gynecologic cancer patients, the cascade genetic testing of their families following the identification of a germline mutation associated with susceptibility to cancer, to highlight disparities between populations, and to present some potential remedies.

Assessment of treatment factors and clinical outcomes in cervical cancer in older women compared to women under 65 years old

OBJECTIVE

This study aims to understand the treatment patterns and clinical outcomes of older women with cervical cancer compared to younger women.

METHODS

Women undergoing care for cervical cancer between 2000 and 2013 at two academic institutions were identified. The cohort of older patients was defined as >65 years old at diagnosis. Patient charts were retrospectively reviewed, and clinical variables were extracted. Fisher's exact tests, logistic regression, and Kaplan-Meier analyses were performed.

RESULTS

From 2000 to 2013 1119 women with cervical cancer were identified. Of these, 191 (17.0%) were >65 years old at the time of diagnosis. Older women were more likely to present with higher stage disease (p < 0.001). Controlling for stage, older women were less likely to undergo surgery during their treatment course (38% versus 70%, p < 0.001) and more likely to undergo radiation (77% versus 52%, p < 0.001), but no more likely to receive chemotherapy (p = 0.34). If they did undergo surgery, older women were less likely to have a pelvic lymph node dissection performed (41% versus 61%, p = 0.04), though the rate of positive pelvic lymph nodes was not different (p = 0.80). Overall survival was decreased in the older cohort (p < 0.001). A multivariate model identified age > 65 (HR 1.76, 95%CI 1.30-2.40), stage (HR 2.77, 95%CI 2.40-3.21), and ever undergoing surgery (HR 0.60, 95%CI 0.44-0.82) as independently associated with overall survival.

CONCLUSIONS

Women over age 65 with cervical cancer are less likely to undergo surgical management and were observed to have a decreased overall survival, even when controlling for use of surgery and stage of disease.

Trends in the use of neoadjuvant chemotherapy for advanced ovarian cancer in the United States

OBJECTIVE

Neoadjuvant chemotherapy and interval debulking surgery for the treatment of advanced ovarian cancer has remained controversial, despite the publication of two randomized trials comparing this modality with primary cytoreductive surgery. This study describes temporal trends in the utilization of neoadjuvant chemotherapy and interval debulking surgery in clinical practice in the United States.

METHODS

We completed a time trend analysis of the National Cancer Data Base. We identified women with stage IIIC and IV epithelial ovarian cancer diagnosed between 2004 and 2013. We categorized subjects as having undergone one of four treatment modalities: primary cytoreductive surgery followed by adjuvant chemotherapy, neoadjuvant chemotherapy followed by interval debulking surgery, surgery only, and chemotherapy only. Temporal trends in the frequency of treatment modalities were evaluated using Joinpoint regression, and χ² tests.

RESULTS

We identified 40,694 women meeting inclusion criteria, of whom 27,032 (66.4%) underwent primary cytoreductive surgery and adjuvant chemotherapy, 5429 (13.3%) received neoadjuvant chemotherapy and interval surgery, 5844 (15.4%) had surgery only, and 2389 (5.9%) received chemotherapy only. The proportion of women receiving neoadjuvant chemotherapy and surgery increased from 8.6% to 22.6% between 2004 and 2013 (p<0.001), and adoption of this treatment modality occurred primarily after 2007 (95%CI 2006-2009; p=0.001). During this period, the proportion of women who received primary cytoreductive surgery and chemotherapy declined from 68.1% to 60.8% (p<0.001), and the proportion who underwent surgery only declined from 17.8% to 9.9% (p<0.001).

CONCLUSION

Between 2004 and 2013 the frequency of neoadjuvant chemotherapy and interval surgery increased significantly in the United States.

GSK3-mediated instability of tubulin polymers is responsible for the failure of immature CD4+CD8+ thymocytes to polarize their MTOC in response to TCR stimulation

Although mature T cells divide and differentiate when they receive strong TCR stimulation, most immature CD4+CD8+ thymocytes die. The molecular basis for this marked difference in response is not known. Observations that TCR-stimulated CD4+CD8+ thymocytes fail to polarize their microtubule-organizing center (MTOC), one of the first events that occurs upon antigen activation of mature T cells, suggests that TCR signaling routes in immature and mature T cells diverge early and upstream of MTOC polarization. To better understand the source of the divergence, we examined the molecular basis for the difference in TCR-mediated MTOC polarization. We show that unstable microtubules are a feature of immature murine CD4+CD8+ thymocytes, which also exhibit higher levels of glycogen synthase kinase 3 (GSK3) activity, a known inhibitor of microtubule stability. Importantly, CD4+CD8+ thymocytes gained the ability to polarize their MTOC in response to TCR signals when GSK3 activity was inhibited. GSK3 inhibition also abrogated TCR-mediated apoptosis of immature thymocytes. Together, our results suggest that a developmentally regulated difference in GSK3 activity has a major influence on immature CD4+CD8+ thymocyte versus mature T-cell responses to TCR stimulation.