Neesha C. Dhani

Randomized Phase II Study of Bevacizumab with Weekly Anetumab Ravtansine or Weekly Paclitaxel in Platinum-Resistant/Refractory High-Grade Ovarian Cancer (NCI Trial)

Abstract Purpose: Mesothelin (MSLN) is highly expressed in high-grade serous/endometrioid ovarian cancers (HGOC). Anetumab ravtansine (AR) is an antibody–drug conjugate directed at the MSLN antigen with a tubulin polymerization inhibitor. We assessed the safety, activity, and pharmacokinetics of the combination AR/bevacizumab (Bev; ARB) versus weekly paclitaxel/Bev (PB) in patients with platinum-resistant/refractory HGOC (prrHGOC). Patients and Methods: Following a run-in phase I study to assess ARB safety, patients with prrHGOC with centrally confirmed MSLN-positive expression were randomized to ARB or PB (weekly paclitaxel 80 mg/m2 with Bev 10 mg/kg biweekly). Patients were stratified by platinum resistance/refractory and prior Bev. The primary endpoint was progression-free survival (PFS), and secondary endpoints were overall response rate, safety, and blood-based angiome biomarker assessment. A futility analysis was planned after 35 PFS events. Results: The combination of Bev (10 mg/kg) biweekly with AR (2.2 mg/kg) weekly was well tolerated. About phase II results, MSLN positivity was 88%, and 57 patients were randomized (28 ARB and 29 PB). Forty-two percentage of patients received prior Bev, and 23% were platinum-refractory. At futility analysis, the median PFS was 5.3 and 12.7 months for ARB and PB, respectively [P = 0.03; HR = 2.02 (1.06–3.86)]. The overall response rate was 21% with ARB and 65% with PB. The most common treatment-related grade ≥3 adverse events were anemia (18%) with ARB and neutropenia (24%) with PB. Higher baseline levels of circulating IL6 were associated with worse PFS, and its levels decreased with PB treatment. Conclusions: Our study stopped at interim analysis highlighting the benefit of PB in prrHGOC as the standard of care.

Rerouting the GPS Directing Immunotherapy in Endometrial Cancer

Summary Mismatch repair (MMR) status alone is insufficient to guide the use of PD-(L)1 monotherapy in patients with endometrial cancer. Additional biomarkers, including tumor mutational burden and combined positive score, may help to identify patients with MMR-proficient tumors with a high probability of benefit from PD-(L)1 monotherapy, and those with MMR-deficient tumors who might require combination strategies. See related article by Oaknin et al., p. 4564

Identifying Mechanisms of Resistance by Circulating Tumor DNA in EVOLVE, a Phase II Trial of Cediranib Plus Olaparib for Ovarian Cancer at Time of PARP Inhibitor Progression

Abstract Purpose: To evaluate the use of blood cell–free DNA (cfDNA) to identify emerging mechanisms of resistance to PARP inhibitors (PARPi) in high-grade serous ovarian cancer (HGSOC). Experimental Design: We used targeted sequencing (TS) to analyze 78 longitudinal cfDNA samples collected from 30 patients with HGSOC enrolled in a phase II clinical trial evaluating cediranib (VEGF inhibitor) plus olaparib (PARPi) after progression on PARPi alone. cfDNA was collected at baseline, before treatment cycle 2, and at end of treatment. These were compared with whole-exome sequencing (WES) of baseline tumor tissues. Results: At baseline (time of initial PARPi progression), cfDNA tumor fractions were 0.2% to 67% (median, 3.25%), and patients with high ctDNA levels (>15%) had a higher tumor burden (sum of target lesions; P = 0.043). Across all timepoints, cfDNA detected 74.4% of mutations known from prior tumor WES, including three of five expected BRCA1/2 reversion mutations. In addition, cfDNA identified 10 novel mutations not detected by WES, including seven TP53 mutations annotated as pathogenic by ClinVar. cfDNA fragmentation analysis attributed five of these novel TP53 mutations to clonal hematopoiesis of indeterminate potential (CHIP). At baseline, samples with significant differences in mutant fragment size distribution had shorter time to progression (P = 0.001). Conclusions: Longitudinal testing of cfDNA by TS provides a noninvasive tool for detection of tumor-derived mutations and mechanisms of PARPi resistance that may aid in directing patients to appropriate therapeutic strategies. With cfDNA fragmentation analyses, CHIP was identified in several patients and warrants further investigation.

A Phase II Randomized Trial of Chemoradiation with or without Metformin in Locally Advanced Cervical Cancer

Abstract Purpose: Tumor hypoxia is associated with poor response to radiation (RT). We previously discovered a novel mechanism of metformin: enhancing tumor RT response by decreasing tumor hypoxia. We hypothesized that metformin would decrease tumor hypoxia and improve cervical cancer response to RT. Patients and Methods: A window-of-opportunity, phase II randomized trial was performed in stage IB–IVA cervical cancer. Patients underwent screening positron emission tomography (PET) imaging with hypoxia tracer fluoroazomycin arabinoside (FAZA). Only patients with FAZA uptake (hypoxic tumor) were included and randomized 2:1 to receive metformin in combination with chemoRT or chemoRT alone. A second FAZA-PET/CT scan was performed after 1 week of metformin or no intervention (control). The primary endpoint was a change in fractional hypoxic volume (FHV) between FAZA-PET scans, compared using the Wilcoxon signed-rank test. The study was closed early due to FAZA availability and the COVID-19 pandemic. Results: Of the 20 consented patients, 6 were excluded due to no FAZA uptake and 1 withdrew. FHV of 10 patients in the metformin arm decreased by an average of 10.2% (44.4%–34.2%) ± SD 16.9% after 1 week of metformin, compared with an average increase of 4.7% (29.1%–33.8%) ± 11.5% for the 3 controls (P = 0.027). Those with FHV reduction after metformin had significantly lower MATE2 expression. With a median follow-up of 2.8 years, the 2-year disease-free survival was 67% for the metformin arm versus 33% for controls (P = 0.09). Conclusions: Metformin decreased cervical tumor hypoxia in this trial that selected for patients with hypoxic tumor. See related commentary by Lyng et al., p. 5233