Pertuzumab Plus Chemotherapy for Platinum-Resistant Ovarian Cancer: Safety Run-in Results of the PENELOPE Trial

Nanoparticle delivery systems to combat drug resistance in ovarian cancer

Due to the lack of early symptoms and difficulty of accurate diagnosis, ovarian cancer is the most lethal gynecological cancer faced by women. First-line therapy includes a combination of tumor resection surgery and chemotherapy regimen. However, treatment becomes more complex upon recurrence due to development of drug resistance. Drug resistance has been linked to many mechanisms, including efflux transporters, apoptosis dysregulation, autophagy, cancer stem cells, epigenetics, and the epithelial-mesenchymal transition. Thus, developing and choosing effective therapies is exceptionally complex. There is a need for increased specificity and efficacy in therapies for drug-resistant ovarian cancer, and research in targeted nanoparticle delivery systems aims to fulfill this challenge. Although recent research has focused on targeted nanoparticle-based therapies, few of these therapies have been clinically translated. In this review, non-viral nanoparticle delivery systems developed to overcome drug-resistance in ovarian cancer were analyzed, including their structural components, surface modifications, and drug-resistance targeted mechanisms.

Patient-reported outcomes and final overall survival results from the randomized phase 3 PENELOPE trial evaluating pertuzumab in low tumor human epidermal growth factor receptor 3 (HER3) mRNA-expressing platinum-resistant ovarian cancer

INTRODUCTION

The PENELOPE trial evaluated pertuzumab added to chemotherapy for biomarker-selected platinum-resistant ovarian cancer. As previously reported, pertuzumab did not statistically significantly improve progression-free survival (primary end point: HR 0.74, 95% CI 0.50 to 1.11), although results in the paclitaxel and gemcitabine cohorts suggested activity. Here, we report final overall survival and patient-reported outcomes.

PATIENTS AND METHODS

Eligible patients had ovarian carcinoma that progressed during/within 6 months of completing ≥4 platinum cycles, low tumor human epidermal growth factor receptor 3 (HER3) mRNA expression, and ≤2 prior chemotherapy lines. Investigators selected single-agent topotecan, gemcitabine or weekly paclitaxel before patients were randomized to either placebo or pertuzumab (840→420 mg every 3 weeks), stratified by selected chemotherapy, prior anti-angiogenic therapy, and platinum-free interval. Final overall survival analysis (key secondary end point) was pre-specified after 129 deaths. Patient-reported outcomes (secondary end point) were assessed at baseline and every 9 weeks until disease progression.

RESULTS

At database lock (June 9, 2016), 130 (83%) of 156 randomized patients had died. Median follow-up was 27 months in the pertuzumab arm versus 26 months in the control arm. In the intent-to-treat population there was no overall survival difference between treatment arms (stratified HR 0.90, 95% CI 0.61 to 1.32; p=0.60). Results in subgroups defined by stratification factors indicated heterogeneity similar to previous progression-free survival results. Updated safety was similar to previously published results. Compliance with patient-reported outcomes questionnaire completion was >75% for all validated patient-reported outcomes measures. Pertuzumab demonstrated neither beneficial nor detrimental effects on patient-reported outcomes compared with placebo, except for increased diarrhea symptoms.

DISCUSSION

Consistent with the primary results, adding pertuzumab to chemotherapy for low tumor HER3 mRNA-expressing platinum-resistant ovarian cancer did not improve overall survival, but showed trends in some cohorts. Except for increased diarrhea symptoms, pertuzumab had no impact on patient-reported outcomes. ClinicalTrials.gov: ClinicalTrials.gov: NCT01684878.

Evolution of anti-HER2 therapies for cancer treatment

The development of HER2-directed monoclonal antibodies and tyrosine kinase inhibitors have provided benefits to cancer patients, as well as produced many insights into the biology of the ErbB receptor family. Current therapies based on ErbB family members have resulted in improved overall survival with associated improvements in quality of life for the cancer patients that respond to treatment. Compared to monotherapy using either two antibodies to block the HER2 receptor blockade or combinatorial approaches with HER2 antibodies and standard therapies has provided additional benefits. Despite the therapeutic success of existing HER2 therapies, personalising treatment and overcoming resistance to these therapies remains a significant challenge. The heterogeneous intra-tumoural HER2 expression and lack of fully predictive and prognostic biomarkers remain significant barriers to improving the use of HER2 antibodies. Imaging modalities using radiolabelled pertuzumab and trastuzumab allow quantitative assessment of intra-tumoural HER2 expression, HER2 antibody saturation and the success of different drug delivery systems to be assessed. Molecular imaging with HER2 antibodies has the potential to be a non-invasive, predictive and prognostic technique capable of influencing therapeutic decisions, predicting response and failure of treatments as well as providing insights into receptor recycling and signalling. Similarly, conjugating HER2 antibodies with novel toxic payloads or combining HER2 antibodies with cellular immunotherapy provide exciting new opportunities for the management of tumours overexpressing HER2. Future research will lead to higher therapeutic responses, lower toxicities and providing insight into the mechanisms of resistance to HER2-targeted treatments.