Patient-Centered Outcomes in ARIEL3, a Phase III, Randomized, Placebo-Controlled Trial of Rucaparib Maintenance Treatment in Patients With Recurrent Ovarian Carcinoma

A B7-H4-Targeting Antibody-Drug Conjugate Shows Antitumor Activity in PARPi and Platinum-Resistant Cancers with B7-H4 Expression

PURPOSE

Platinum and PARP inhibitors (PARPi) demonstrate activity in breast and ovarian cancers, but drug resistance ultimately emerges. Here, we examine B7-H4 expression in primary and recurrent high-grade serous ovarian carcinoma (HGSOC) and the activity of a B7-H4-directed antibody-drug conjugate (B7-H4-ADC), using a pyrrolobenzodiazepine-dimer payload, in PARPi- and platinum-resistant HGSOC patient-derived xenograft (PDX) models.

EXPERIMENTAL DESIGN

B7-H4 expression was quantified by flow cytometry and IHC. B7-H4-ADC efficacy was tested against multiple cell lines in vitro and PDX in vivo. The effect of B7-H4-ADC on cell cycle, DNA damage, and apoptosis was measured using flow cytometry.

RESULTS

B7-H4 is overexpressed in 92% of HGSOC tumors at diagnosis (n = 12), persisted in recurrent matched samples after platinum treatment, and was expressed at similar levels across metastatic sites after acquired multi-drug resistance (n = 4). Treatment with B7-H4-ADC resulted in target-specific growth inhibition of multiple ovarian and breast cancer cell lines. In platinum- or PARPi-resistant ovarian cancer cells, B7-H4-ADC significantly decreased viability and colony formation while increasing cell-cycle arrest and DNA damage, ultimately leading to apoptosis. Single-dose B7-H4-ADC led to tumor regression in 65.5% of breast and ovarian PDX models (n = 29), with reduced activity in B7-H4 low or negative models. In PARPi and platinum-resistant HGSOC PDX models, scheduled B7-H4-ADC dosing led to sustained tumor regression and increased survival.

CONCLUSIONS

These data support B7-H4 as an attractive ADC target for treatment of drug-resistant HGSOC and provide evidence for activity of an ADC with a DNA-damaging payload in this population. See related commentary by Veneziani et al., p. 1434.

Estimating optimal individualized treatment rules with multistate processes

Multistate process data are common in studies of chronic diseases such as cancer. These data are ideal for precision medicine purposes as they can be leveraged to improve more refined health outcomes, compared to standard survival outcomes, as well as incorporate patient preferences regarding quantity versus quality of life. However, there are currently no methods for the estimation of optimal individualized treatment rules with such data. In this paper, we propose a nonparametric outcome weighted learning approach for this problem in randomized clinical trial settings. The theoretical properties of the proposed methods, including Fisher consistency and asymptotic normality of the estimated expected outcome under the estimated optimal individualized treatment rule, are rigorously established. A consistent closed-form variance estimator is provided and methodology for the calculation of simultaneous confidence intervals is proposed. Simulation studies show that the proposed methodology and inference procedures work well even with small-sample sizes and high rates of right censoring. The methodology is illustrated using data from a randomized clinical trial on the treatment of metastatic squamous-cell carcinoma of the head and neck.

Heterogeneity and treatment landscape of ovarian carcinoma

Ovarian carcinoma is characterized by heterogeneity at the molecular, cellular and anatomical levels, both spatially and temporally. This heterogeneity affects response to surgery and/or systemic therapy, and also facilitates inherent and acquired drug resistance. As a consequence, this tumour type is often aggressive and frequently lethal. Ovarian carcinoma is not a single disease entity and comprises various subtypes, each with distinct complex molecular landscapes that change during progression and therapy. The interactions of cancer and stromal cells within the tumour microenvironment further affects disease evolution and response to therapy. In past decades, researchers have characterized the cellular, molecular, microenvironmental and immunological heterogeneity of ovarian carcinoma. Traditional treatment approaches have considered ovarian carcinoma as a single entity. This landscape is slowly changing with the increasing appreciation of heterogeneity and the recognition that delivering ineffective therapies can delay the development of effective personalized approaches as well as potentially change the molecular and cellular characteristics of the tumour, which might lead to additional resistance to subsequent therapy. In this Review we discuss the heterogeneity of ovarian carcinoma, outline the current treatment landscape for this malignancy and highlight potentially effective therapeutic strategies in development.

Q-TWiST analysis of survival benefits with brigatinib versus crizotinib in patients with anaplastic lymphoma kinase-positive non-small cell lung cancer based on results of the ALTA-1L trial

OBJECTIVES

The ALTA-1L phase 3 open-label trial demonstrated increased progression-free survival (PFS) with brigatinib versus crizotinib in patients with anaplastic lymphoma kinase-positive (ALK-positive) locally advanced or metastatic non-small cell lung cancer (NSCLC) previously untreated with ALK-targeted therapy. This post-hoc analysis of data from the ALTA-1L trial used the quality-adjusted (QA) time without symptoms of disease or toxicity (Q-TWiST) methodology to compare the QA survival benefit of brigatinib versus crizotinib in this patient population.

PATIENTS AND METHODS

The Q-TWiST analysis was performed using final (January 29, 2021) individual patient-level blinded independent review committee (BIRC)- and investigator-assessed survival data for brigatinib (n = 137) and crizotinib (n = 138) in adult patients (N = 275) with ALK-positive locally advanced or metastatic NSCLC previously untreated with ALK-targeted therapy. Q-TWiST was compared between the two treatments. Subgroup analyses were performed in patients stratified by various clinicopathological characteristics, including presence or absence of brain metastases at baseline.

RESULTS

Brigatinib was associated with significantly longer time without symptoms of disease or toxicity (P < 0.001) than crizotinib, with significantly greater Q-TWiST (mean [SE] months: BIRC-assessed, 28.2 [1.2] versus 25.1 [1.1], P = 0.045; investigator-assessed, 28.5 [1.2] versus 24.8 [1.1], P = 0.018). Relative gains in Q-TWiST with brigatinib compared to crizotinib were clinically meaningful (BIRC-assessed, 10.4%; investigator-assessed, 12.3%). Patients with brain metastases at baseline receiving brigatinib had significantly greater Q-TWiST (mean [SE] months: BIRC-assessed, 29.0 [1.9] versus 19.0 [1.9], P = 0.0001) than those receiving crizotinib.

CONCLUSION

First-line brigatinib treatment was associated with significant and clinically meaningful gains in Q-TWiST compared to crizotinib in patients with ALK-positive locally advanced or metastatic NSCLC, supporting the results of the ALTA-1L trial and brigatinib as a safe and effective first-line treatment for ALK-positive NSCLC.

Patient-reported outcomes of maintenance rucaparib in patients with recurrent ovarian carcinoma in ARIEL3, a phase III, randomized, placebo-controlled trial

PURPOSE

To compare NFOSI-18 Disease Related Symptoms - Physical (DRSP), Total score, and side effect bother between maintenance rucaparib (600 mg twice daily) vs. placebo in the phase III ARIEL3 trial.

METHODS

ARIEL3 (NCT01968213) included patients with ovarian carcinoma who responded to second-line or later platinum-based chemotherapy. The NFOSI-18 DRS-P and Total scales were secondary endpoints. The NFOSI-18 contains a side effect impact item (GP5): "I am bothered by side effects of treatment." We compared treatment arms on change from baseline of DRS-P and Total scores using mixed models with repeated measures (MRMM). Time to first and confirmed deterioration of NFOSI-18 DRS-P and Total scales were analyzed using Cox regression. We also calculated the proportion of patients reporting moderate to high side effect bother on GP5.

RESULTS

In the intention-to-treat (ITT) cohort, mean change from baseline favored the placebo. Compared to placebo, rucaparib was associated with higher risk of deterioration [e.g., 4-point deteriorator definition hazard ratio (HR): 1.85; 95% CI: 1.46, 2.36; median time to first deterioration on DRSP: 1.9 vs. 7.0 months]. Confirmed deterioration results resembled those for first deterioration. Proportions of patients reporting moderate/high side effect bother on GP5 fluctuated around 20% across treatment cycles. Results in BRCA mutant and homologous recombination deficient cohorts were generally similar to those from the ITT cohort.

CONCLUSION

This placebo-controlled study in the maintenance therapy setting provides a unique view of the impact of PARP inhibition on the patient-reported outcomes that are commonly used in ovarian cancer clinical trials. Information regarding the adverse side effect impact of PARP inhibitors should be weighed against their clinical benefit.

PARP Inhibitors in Ovarian Cancer: A Review

Poly(ADP-ribose) polymerase (PARP) inhibitors (PARPis) have transformed the ovarian cancer (OC) treatment landscape. This narrative review provides a comprehensive overview of data for the PARPis olaparib, niraparib, and rucaparib in patients with OC and discusses their role in disease management, with a focus on the use of PARPis as maintenance therapy in the United States (US). Olaparib was the first PARPi to be approved as first-line maintenance monotherapy in the US, with maintenance niraparib subsequently approved in the first-line setting. Data also support the efficacy of rucaparib as first-line maintenance monotherapy. PARPi maintenance combination therapy (olaparib plus bevacizumab) also provides benefit in patients with newly diagnosed advanced OC whose tumors tested positive for homologous recombination deficiency (HRD). Biomarker testing is critical in the newly diagnosed setting to identify patients most likely to benefit from PARPi maintenance therapy and guide treatment decisions. Clinical trial data support the use of PARPis (olaparib, niraparib, rucaparib) as second-line or later maintenance therapy in patients with platinum-sensitive relapsed OC. Although distinct differences in tolerability profile were observed between PARPis, they were generally well tolerated, with the majority of adverse events managed by dose modification. PARPis had no detrimental effect on patients' health-related quality of life. Real-world data support the use of PARPis in OC, although some differences between PARPis are apparent. Data from trials investigating novel combination strategies, such as PARPis plus immune checkpoint inhibitors, are awaited with interest; the optimal sequencing of novel therapies in OC remains to be established.

PARP inhibitors: risk factors for toxicity and matching patients to the proper poly (ADP-ribose) polymerase inhibitor (PARPi) therapy

The past 5 years have seen several fundamental advances in ovarian cancer, with important new insights towards novel therapeutic opportunities within the DNA repair pathway. With the incorporation of poly (ADP-ribose) polymerase inhibitors (PARPi) into maintenance treatment regimens, the management of short- and long-term adverse events are key clinical priorities. Currently, three different PARPi are clinically beneficial and have been approved for primary and recurrent ovarian cancer: olaparib, niraparib, and rucaparib. The duration of treatment with PARPi in patients with ovarian cancer varies; patients can receive treatment for up to 2 or 3 years in first-line setting, or continue treatment until unacceptable toxicity or progression occurs in recurrent disease. Despite their similar mechanisms of action, these three inhibitors have specific toxicity profiles, which may lead to dose interruptions or discontinuation of treatment. This review summarizes the current indications for PARPi, including their role in recurrent and first-line maintenance treatment for advanced ovarian cancer. We also outline dose modifications leading to treatment disruption and potential changes in quality of life after prolonged treatment. Finally, we highlight the patient groups most likely to benefit from each of the three different PARPi.

Effect of ERCC1 polymorphisms on the response to platinum-based chemotherapy: A systematic review and meta-analysis based on Asian population

BACKGROUND

Platinum-based chemotherapy is one of the most common treatments for many cancers; however, the effect of chemotherapy varies from individual to individual. Excision repair cross complementation group 1 (ERCC1) is widely recognized as a key gene regulating nucleotide excision repair (NER) and is closely associated with platinum response. Many studies have yielded conflicting results regarding whether ERCC1 polymorphisms can affect the response to platinum and overall survival (OS). Therefore, it is necessary to perform a meta-analysis of patients with specific races and cancer types.

METHODS

Eight databases (EMBASE, PubMed, Cochrane Library, Chinese National Knowledge Infrastructure, Scopus, VIP, China Biology Medicine disc and Wanfang databases) were searched. Results were expressed in terms of odds ratios (ORs), hazard ratios (HRs) and 95% CIs.

RESULTS

In this study, rs11615, rs2298881 and rs3212986 SNPs were studied. In the comparison between CT and TT on the response to platinum, esophageal cancer [I2 = 0%, OR = 6.18, 95% CI(1.89,20.23), P = 0.003] and ovarian cancer [I2 = 0%, OR = 4.94, 95% CI(2.21,11.04), P<0.001] showed that the rs11615 CT genotype predicted a better response. In the comparison between CC and TT, ovarian cancer [I2 = 48.0%, OR = 6.15, 95% CI (2.56,14.29), P<0.001] indicated that the CC genotype predicted a better response. In the meta-analysis of OS, the CC genotype was related to longer OS than TT in ovarian cancer [TT vs CC: I2 = 57.7%, HR = 1.71, 95% CI (1.18, 2.49), P<0.001].

CONCLUSION

The ERCC1 rs11615 polymorphism was related to the response to platinum and OS, but the correlation is based on specific cancer types in the Asian population.

Patient-Reported Outcomes in Ovarian Cancer: Facilitating and Enhancing the Reporting of Symptoms, Adverse Events, and Subjective Benefit of Treatment in Clinical Trials and Clinical Practice

Patient-reported outcomes (PROs) provide a valid, standardized way of assessing symptoms, adverse events and the subjective benefit of treatment from the patient's perspective. Assessment of PROs is critical in ovarian cancer due to the high morbidity of the disease and its treatments. Several well-validated PRO measures are available to assess PROs in ovarian cancer. Their inclusion in clinical trials can provide evidence on the benefits and harms of new treatments based on patients' experiences to guide improvements in clinical practice and health policy. Aggregate PRO data collected in clinical trials can be used to inform patients about likely treatment impacts and assist them to make informed treatment decisions. In clinical practice, PRO assessments can facilitate monitoring of a patient's symptoms throughout treatment and follow-up to guide their clinical management; in this context, an individual patient's responses can facilitate communication with their treating clinician about troublesome symptoms and their impact on their quality of life. This literature review aimed to provide clinicians and researchers with a better understanding of why and how PROs can be incorporated into ovarian cancer clinical trials and routine clinical practice. We discuss the importance of assessing PROs throughout the ovarian cancer disease and treatment trajectory in both clinical trials and clinical practice, and provide examples from existing literature to illustrate the uses of PROs as the goals of treatment change in each setting.

Advances in small molecule maintenance therapies for high-grade serous ovarian cancer

INTRODUCTION

Ovarian cancer is one of the most lethal gynecological tumors with a lack of effective treatment modalities especially in advanced/recurrent disease. Nevertheless, recently, new small molecules have emerged as an effective approach for the management of ovarian cancer patients, especially in the maintenance setting.

AREAS COVERED

This review summarizes the role of small molecules used in the management of high-grade serous ovarian cancer. The authors performed a critical review of current evidence and ongoing studies. Of note, tyrosine kinase inhibitors (TKIs) and poly(ADP-ribose) polymerase (PARP) inhibitors are the most intriguing medications in this setting.

EXPERT OPINION

Protein-targeted therapies against tumor tissues have progressed significantly in the last years due to an enhanced knowledge of the biological and molecular processes of carcinogenesis. Treatment with small molecules allows the targeting of specific proteins involved in cancer biology. TKIs seem promising but further data are necessary to assess the pros and cons of adopting this treatment modality. PARP inhibitors represent the new standard of care for ovarian cancer patients harboring either a BRCA mutation or with homologous recombination deficiency (HRD). Interestingly, the accumulation of data has highlighted that PARP inhibitors provide benefits even in patients with HR proficient tumors.

Molecular Targeted Therapy in Oncology Focusing on DNA Repair Mechanisms

DNA repair mechanisms are essential for maintaining cellular homeostasis. Malfunction of these repair mechanisms leads to cellular DNA mutations, carcinogenic transformation, and cell death. These same defects also create vulnerabilities that are relatively specific to cancer cells, and which could potentially be exploited to increase the therapeutic index of anticancer treatments and thereby improve patient outcomes. The targeted therapy based on inhibiting the DNA damage response (DDR) opens a new therapeutic landscape for patients with deficient DDR. Currently there are two DNA repair mechanisms that are used as targets for molecular therapies: Mitsmach Repair (MMR) and Homologous Recombination Repair (HRR). These molecular targets allow for immunotherapy treatments based on "checkpoint inhibitors" (ICIs) drugs and "PARP inhibitor" (PARPi) drugs in different solid tumors. In this review we will describe the state of the art of this interesting mechanism and explain the options for treatment based on these alterations. Moreover, many clinical trials are currently underway exploring better treatment options for dMMR and HRD patients with different solid tumours.

Quality-adjusted time without symptoms of disease or toxicity and quality-adjusted progression-free survival with niraparib maintenance in first-line ovarian cancer in the PRIMA trial

Background:

The PRIMA phase 3 trial showed niraparib significantly prolongs median progression-free survival (PFS) versus placebo in patients with advanced ovarian cancer (OC) responsive to first-line platinum-based chemotherapy, including those who had tumors with homologous recombination deficiency (HRd). This analysis of PRIMA examined the quality-adjusted PFS (QA-PFS) and quality-adjusted time without symptoms of disease or toxicity (Q-TWiST) of patients on maintenance niraparib versus placebo.

Methods:

Patients were randomized 2:1 to receive once-daily maintenance niraparib (n = 487) or placebo (n = 246). QA-PFS was defined as the PFS of patients adjusted for their health-related quality of life (HRQoL) prior to disease progression, measured using European Quality of Life Five-Dimension (EQ-5D) questionnaire index scores from the PRIMA trial. Q-TWiST was calculated by combining data on PFS, duration of symptomatic grade ⩾2 adverse events (fatigue or asthenia, nausea, vomiting, abdominal pain, and abdominal bloating) prior to disease progression, and EQ-5D index scores. Analyses used data collected up to the last date of PFS assessment (May 17, 2019).

Results:

The restricted mean QA-PFS was significantly longer with niraparib versus placebo in the HRd (n = 373) and overall intention-to-treat (ITT; n = 733) populations (mean gains of 6.5 [95% confidence interval; CI, 3.9–8.9] and 4.1 [95% CI, 2.2–5.8] months, respectively). There were also significant improvements in restricted mean Q-TWiST for niraparib versus placebo (mean gains of 5.9 [95% CI, 3.5–8.6] and 3.5 [95% CI, 1.7–5.6] months, respectively) in the HRd and ITT populations.

Conclusions:

In patients with advanced OC, first-line niraparib maintenance was associated with significant gains in QA-PFS and Q-TWiST versus placebo. These findings demonstrate that niraparib maintenance treatment is associated with a PFS improvement and that treatment benefit is maintained even when HRQoL and/or toxicity data are combined with PFS in a single measure.

Trial registration:

ClinicalTrials.gov: NCT02655016; trial registration date: January 13, 2016

Plain language summary

Background: In a large clinical trial called PRIMA, patients with advanced cancer of the ovary (ovarian cancer) were given either niraparib (a type of cancer medicine) or placebo (a pill containing no medicine/active substances) after having chemotherapy (another type of cancer medicine). Taking niraparib after chemotherapy is called maintenance therapy and aims to give patients more time before their cancer returns or gets worse than if they were not given any further treatment. In the PRIMA trial, patients who took niraparib did have more time before their cancer progressed than if they took placebo. However, it is important to consider patients’ quality of life, which can be made worse by cancer symptoms and/or side effects of treatment. Here, we assessed the overall benefit of niraparib for patients in PRIMA.

Methods: Both the length of time before disease progression (or survival time) and quality of life were considered using two different analyses:

● The first analysis was called quality-adjusted PFS (QA-PFS) and looked at how long patients survived with good quality of life.

● The second analysis was called quality-adjusted time without symptoms of disease or toxicity (Q-TWiST) and looked at how long patients survived without cancer symptoms or treatment side effects.

Results: The PRIMA trial included 733 patients; 487 took niraparib and 246 took placebo. Around half of the patients in both groups had a type of ovarian cancer that responds particularly well to drugs like niraparib – they are known as homologous recombination deficiency (HRd) patients.

● When information on quality of life (collected from patient questionnaires) and survival was combined in the QA-PFS analysis, HRd patients who took niraparib had approximately 6.5 months longer with a good quality of life before disease progression than those who took placebo. In the overall group of patients (including HRd patients and non-HRd patients), those who took niraparib had approximately 4 months longer than with placebo.

● Using the second analysis (Q-TWiST) to combine information on survival with cancer symptoms and treatment side effects, the HRd patients taking niraparib had approximately 6 months longer without cancer symptoms or treatment side effects (such as nausea or vomiting) than patients taking placebo. In the overall group of patients, those taking niraparib had approximately 3.5 months longer without these cancer symptoms/side effects than patients receiving placebo.

Conclusions: These results show that the survival benefits of niraparib treatment remain when accounting for patients’ quality of life. These benefits were seen not only in HRd patients who are known to respond better to niraparib, but in the overall group of patients who took niraparib.

Health-related quality of life analysis in ovarian cancer clinical trials involving PARP inhibitors: a critical methodological perspective

The poly (ADP-ribose) polymerase inhibitors (PARPi) have yielded significant clinical benefits as maintenance therapy in women with newly diagnosed and relapsed platinum-sensitive advanced ovarian cancer. These drugs were approved based on progression-free survival, the primary endpoint of their respective pivotal trials. Health-related quality of life (HRQoL) and/or patient-reported outcomes were included in these trials as a secondary exploratory endpoint. Nevertheless, many weaknesses in the analysis of HRQoL across these trials can be noticed. Heterogeneity and suboptimal HRQoL analysis in oncology trials contribute to misconceptions about this endpoint among oncologists and prevent quality of life as being an endpoint used for approvals. In this article, we discuss these HRQoL results from a methodological perspective and propose some solutions for improvement that could be used by regulatory and academic institutions running ovarian cancers trials. Notably, we suggest to measure and analyze HRQoL data after disease progression, to focus dedicated papers on the statistical analyses of HRQoL recommended by the SISAQOL consortium (linear mixed model for repeated measures and time-to-event approaches) and to communicate on available guidelines to ensure compliance with best international practices regarding the measurement and analysis of HRQoL.

Clinical trials of immunotherapy in triple-negative breast cancer

Purpose

Immunotherapy has started to transform the treatment of triple-negative breast cancer (TNBC), in part due to the unique immunogenicity of this breast cancer subtype. This review summarizes clinical studies of immunotherapy in advanced and early-stage TNBC.

Findings

Initial studies of checkpoint blockade monotherapy demonstrated occasional responses, especially in patients with untreated programmed death-ligand 1 (PD-L1) positive advanced TNBC, but failed to confirm a survival advantage over chemotherapy. Nonetheless, pembrolizumab monotherapy has tumor agnostic approval for microsatellite instability-high or high tumor mutational burden cancers, and thus can be considered for select patients with advanced TNBC. Combination chemoimmunotherapy approaches have been more successful, and pembrolizumab is approved for PD-L1 positive advanced TNBC in combination with chemotherapy. This success has been translated to the curative setting, where pembrolizumab is now approved in combination with neoadjuvant chemotherapy for high-risk early-stage TNBC.

Conclusion

Immunotherapy has been a welcome addition to the growing armamentarium for TNBC, but responses remain limited to a subset of patients. Innovative strategies are under investigation in an attempt to induce immune responses in resistant tumors—with regimens incorporating small-molecule inhibitors, novel immune checkpoint targets, and intratumoral injections that directly alter the tumor microenvironment. As the focus shifts toward the use of immunotherapy for early-stage TNBC, it will be critical to identify those who derive the most benefit from treatment, given the potential for irreversible autoimmune toxicity and the lack of predictive accuracy of PD-L1 expression in the early-stage setting.

Niraparib treatment for patients with BRCA-mutated ovarian cancer: review of clinical data and therapeutic context

We reviewed clinical data for niraparib monotherapy in BRCA-mutated (BRCAm) epithelial ovarian cancer (OC), contextualizing results with data from other poly(ADP-ribose) polymerase inhibitors (PARPis). Niraparib reduced the likelihood of progression or death by 60% as first-line maintenance therapy and by 73-78% in recurrent disease. In heavily pretreated OC, efficacy was greater in the BRCAm versus non-BRCAm cohort. Quality-of-life (QoL) was maintained throughout treatment. Adverse events were consistent with the known niraparib safety profile. Cumulative efficacy, safety and QoL evidence demonstrate niraparib maintenance monotherapy has a positive benefit:risk ratio in BRCAm OC. Niraparib significantly improved progression-free survival as first-line maintenance therapy in all patients with OC (i.e., of any biomarker status).

PARP inhibitors as single agents and in combination therapy: the most promising treatment strategies in clinical trials for BRCA-mutant ovarian and triple-negative breast cancers

INTRODUCTION

Poly (ADP-ribose) polymerase inhibitors (PARPis) are an exciting class of agents that have shown efficacy, particularly for BRCA-mutant triple-negative breast cancer (TNBC) and high-grade serous ovarian cancer (HGSOC). However, most patients who receive PARPi as their standard of care therapy inevitably develop resistance and this underscores the need to identify additional targets that can circumvent such resistance. Combination treatment strategies have been developed in preclinical and clinical studies to address the challenges of efficacy and resistance.

AREAS COVERED

This review examines completed or ongoing clinical trials of PARPi mono- and combination therapies. PARPi monotherapy in HER2 negative breast (HR+ and TNBC subtypes) and ovarian cancer is a focal point. The authors propose potential strategies that might overcome resistance to PARPi and discuss key questions and future directions.

EXPERT OPINION

While the advent of PARPis has significantly improved the treatment of tumors with defects in DNA damage and repair pathways, careful patient selection will be essential to enhance these treatments. The identification of molecular biomarkers to predict disease response and progression is an endeavor.

Adverse events of targeted therapies approved for women's cancers

Breast cancer and gynecologic cancers affect >3 million women worldwide each year. With advances in precision medicine, a growing number of targeted therapies have been approved recently, and new therapeutic classes have emerged, including cell cycle inhibitors for hormone receptor positive breast cancer, antibody drug conjugate for human epidermal growth factor receptor 2 positive and triple negative breast cancer, and poly-ADP-ribose polymerase inhibitors for ovarian cancer. This article focuses first on the challenges for health care systems to address the specificities of each emerging targeted therapy and new issues raised by oral antitumor treatments, including individualization of prescriptions, drug–drug interaction assessment, pharmaceutical counseling, patient education, and outpatient management. Then, we provide an overview of the main adverse effects of targeted therapies approved for breast and gynecologic cancers, such as hematologic toxicity of cyclin-dependent kinase 4/6 inhibitors and poly-ADP-ribose polymerase inhibitors, metabolic disorders of phosphatidylinositol-3-kinase/Akt/mammalian target of rapamycin inhibitors, and cardiovascular toxicity of agents targeting human epidermal growth factor receptor 2.

PARP Inhibitors and Haematological Malignancies-Friend or Foe?

Simple Summary

PARP inhibitors are a class of orally active drugs that kill a range of cancer types by inducing synthetic lethality. The usefulness of PARP inhibitors for the treatment of haematological malignancies has begun to be explored in a variety of both pre-clinical models and human clinical trials. Despite being largely considered safe and well tolerated, secondary haematological malignancies have arisen in patients following treatment with PARP inhibitors, raising concerns about their use. In this review, we discuss the potential benefits and risks for using PARP inhibitors as treatments for haematological malignancies.

Abstract

Since their introduction several years ago, poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) have become the standard of care for breast and gynaecological cancers with BRCA gene mutations. Given that PARPi act by exploiting defective DNA repair mechanisms within tumour cells, they should be ideally suited to combatting haematological malignancies where these pathways are notoriously defective, even though BRCA mutations are rare. To date, despite promising results in vitro, few clinical trials in humans for haematological malignancies have been performed, and additional investigation is required. Paradoxically, secondary haematological malignancies have arisen in patients after treatment with PARPi, raising concerns about their potential use as therapies for any blood or bone marrow-related disorders. Here, we provide a comprehensive review of the biological, pre-clinical, and clinical evidence for and against treating individual haematological malignancies with approved and experimental PARPi. We conclude that the promise of effective treatment still exists, but remains limited by the lack of investigation into useful biomarkers unique to these malignancies.

DNA damage repair: historical perspectives, mechanistic pathways and clinical translation for targeted cancer therapy

Genomic instability is the hallmark of various cancers with the increasing accumulation of DNA damage. The application of radiotherapy and chemotherapy in cancer treatment is typically based on this property of cancers. However, the adverse effects including normal tissues injury are also accompanied by the radiotherapy and chemotherapy. Targeted cancer therapy has the potential to suppress cancer cells' DNA damage response through tailoring therapy to cancer patients lacking specific DNA damage response functions. Obviously, understanding the broader role of DNA damage repair in cancers has became a basic and attractive strategy for targeted cancer therapy, in particular, raising novel hypothesis or theory in this field on the basis of previous scientists' findings would be important for future promising druggable emerging targets. In this review, we first illustrate the timeline steps for the understanding the roles of DNA damage repair in the promotion of cancer and cancer therapy developed, then we summarize the mechanisms regarding DNA damage repair associated with targeted cancer therapy, highlighting the specific proteins behind targeting DNA damage repair that initiate functioning abnormally duo to extrinsic harm by environmental DNA damage factors, also, the DNA damage baseline drift leads to the harmful intrinsic targeted cancer therapy. In addition, clinical therapeutic drugs for DNA damage and repair including therapeutic effects, as well as the strategy and scheme of relative clinical trials were intensive discussed. Based on this background, we suggest two hypotheses, namely "environmental gear selection" to describe DNA damage repair pathway evolution, and "DNA damage baseline drift", which may play a magnified role in mediating repair during cancer treatment. This two new hypothesis would shed new light on targeted cancer therapy, provide a much better or more comprehensive holistic view and also promote the development of new research direction and new overcoming strategies for patients.

Rucaparib maintenance treatment for recurrent ovarian carcinoma: the effects of progression-free interval and prior therapies on efficacy and safety in the randomized phase III trial ARIEL3

INTRODUCTION

In ARIEL3 (NCT01968213), the poly(adenosine diphosphate-ribose) polymerase inhibitor rucaparib significantly improved progression-free survival versus placebo regardless of biomarker status when used as maintenance treatment for recurrent ovarian cancer. The aim of the current analyses was to evaluate the efficacy and safety of rucaparib in subgroups based on progression-free interval following penultimate platinum, number of prior chemotherapies, and prior use of bevacizumab.

METHODS

Patients were randomized 2:1 to rucaparib 600 mg twice daily or placebo. Within subgroups, progression-free survival was assessed in prespecified, nested cohorts: BRCA-mutant, homologous recombination deficient (BRCA-mutant or wild-type BRCA/high genomic loss of heterozygosity), and the intent-to-treat population.

RESULTS

In the intent-to-treat population, median investigator-assessed progression-free survival was 8.2 months with rucaparib versus 4.1 months with placebo (n=151 vs n=76; HR 0.33, 95% CI 0.24 to 0.46, p<0.0001) for patients with progression-free interval 6 to ≤12 months, and 13.6 versus 5.6 months (n=224 vs n=113; HR 0.39, 95% CI 0.30 to 0.52, p<0.0001) for those with progression-free interval >12 months. Median progression-free survival was 10.4 versus 5.4 months (n=231 vs n=124; HR 0.42, 95% CI 0.32 to 0.54, p<0.0001) for patients who had received two prior chemotherapies, and 11.1 versus 5.3 months (n=144 vs n=65; HR 0.28, 95% CI 0.19 to 0.41, p<0.0001) for those who had received ≥3 prior chemotherapies. Median progression-free survival was 10.3 versus 5.4 months (n=83 vs n=43; HR 0.42, 95% CI 0.26 to 0.68, p=0.0004) for patients who had received prior bevacizumab, and 10.9 versus 5.4 months (n=292 vs n=146; HR 0.35, 95% CI 0.28 to 0.45, p<0.0001) for those who had not. Across subgroups, median progression-free survival was also significantly longer with rucaparib versus placebo in the BRCA-mutant and homologous recombination deficient cohorts. Safety was consistent across subgroups.

CONCLUSIONS

Rucaparib maintenance treatment significantly improved progression-free survival versus placebo irrespective of progression-free interval following penultimate platinum, number of lines of prior chemotherapy, and previous use of bevacizumab.

Differences in PARP Inhibitors for the Treatment of Ovarian Cancer: Mechanisms of Action, Pharmacology, Safety, and Efficacy

Poly(ADP-ribose) polymerases (PARP) are proteins responsible for DNA damage detection and signal transduction. PARP inhibitors (PARPi) are able to interact with the binding site for PARP cofactor (NAD+) and trapping PARP on the DNA. In this way, they inhibit single-strand DNA damage repair. These drugs have been approved in recent years for the treatment of ovarian cancer. Although they share some similarities, from the point of view of the chemical structure and pharmacodynamic, pharmacokinetic properties, these drugs also have some substantial differences. These differences may underlie the different safety profiles and activity of PARPi.

Patient-centred outcomes and effect of disease progression on health status in patients with newly diagnosed advanced ovarian cancer and a BRCA mutation receiving maintenance olaparib or placebo (SOLO1): a randomised, phase 3 trial

BACKGROUND

In the phase 3 SOLO1 trial, maintenance olaparib provided a significant progression-free survival benefit versus placebo in patients with newly diagnosed, advanced ovarian cancer and a BRCA mutation in response after platinum-based chemotherapy. We analysed health-related quality of life (HRQOL) and patient-centred outcomes in SOLO1, and the effect of radiological disease progression on health status.

METHODS

SOLO1 is a randomised, double-blind, international trial done in 118 centres and 15 countries. Eligible patients were aged 18 years or older; had an Eastern Cooperative Oncology Group performance status score of 0-1; had newly diagnosed, advanced, high-grade serous or endometrioid ovarian cancer, primary peritoneal cancer, or fallopian tube cancer with a BRCA mutation; and were in clinical complete or partial response to platinum-based chemotherapy. Patients were randomly assigned (2:1) to either 300 mg olaparib tablets or placebo twice per day using an interactive voice and web response system and were treated for up to 2 years. Treatment assignment was masked for patients and for clinicians giving the interventions, and those collecting and analysing the data. Randomisation was stratified by response to platinum-based chemotherapy (clinical complete or partial response). HRQOL was a secondary endpoint and the prespecified primary HRQOL endpoint was the change from baseline in the Functional Assessment of Cancer Therapy-Ovarian Cancer Trial Outcome Index (TOI) score for the first 24 months. TOI scores range from 0 to 100 (higher scores indicated better HRQOL), with a clinically meaningful difference defined as a difference of at least 10 points. Prespecified exploratory endpoints were quality-adjusted progression-free survival and time without significant symptoms of toxicity (TWiST). HRQOL endpoints were analysed in all randomly assigned patients. The trial is ongoing but closed to new participants. This trial is registered with ClinicalTrials.gov, NCT01844986.

FINDINGS

Between Sept 3, 2013, and March 6, 2015, 1084 patients were enrolled. 693 patients were ineligible, leaving 391 eligible patients who were randomly assigned to olaparib (n=260) or placebo (n=131; one placebo patient withdrew before receiving any study treatment), with a median duration of follow-up of 40·7 months (IQR 34·9-42·9) for olaparib and 41·2 months (32·2-41·6) for placebo. There was no clinically meaningful change in TOI score at 24 months within or between the olaparib and placebo groups (adjusted mean change in score from baseline over 24 months was 0·30 points [95% CI -0·72 to 1·32] in the olaparib group vs 3·30 points [1·84 to 4·76] in the placebo group; between-group difference of -3·00, 95% CI -4·78 to -1·22; p=0·0010). Mean quality-adjusted progression-free survival (olaparib 29·75 months [95% CI 28·20-31·63] vs placebo 17·58 [15·05-20·18]; difference 12·17 months [95% CI 9·07-15·11], p<0·0001) and the mean duration of TWiST (olaparib 33·15 months [95% CI 30·82-35·49] vs placebo 20·24 months [17·36-23·11]; difference 12·92 months [95% CI 9·30-16·54]; p<0·0001) were significantly longer with olaparib than with placebo.

INTERPRETATION

The substantial progression-free survival benefit provided by maintenance olaparib in the newly diagnosed setting was achieved with no detrimental effect on patients' HRQOL and was supported by clinically meaningful quality-adjusted progression-free survival and TWiST benefits with maintenance olaparib versus placebo.

FUNDING

AstraZeneca and Merck Sharp & Dohme.

Lived experiences of women reporting fatigue during PARP inhibitor maintenance treatment for advanced ovarian cancer: A qualitative study

OBJECTIVE

Oral PARP inhibitors (PARPi) have dramatically changed the treatment landscape for patients with advanced ovarian cancer. However, a subset of patients discontinue PARPi due to treatment-related fatigue. The current study sought to explore patients' lived experiences with fatigue on PARPi.

METHODS

We conducted individual semi-structured interviews with N = 23 women receiving PARPi for advanced ovarian cancer who reported moderate to severe fatigue. Audiotaped interviews were transcribed and we used thematic analysis to code transcripts for emergent themes.

RESULTS

Four overarching themes emerged. First, participants described their fatigue as milder than what they experienced on intravenous chemotherapy, but noted it consistently limited their daily activities, including work, and interfered with participation in family and social events. Second, fatigue negatively impacted participants' sense of self and identity. Third, most wanted to continue treatment and believed discontinuing PARPi would lead to a cancer recurrence or death. Finally, many participants reported that their support networks were unaware of their ongoing cancer treatment or the resulting fatigue; a situation that may prove isolating and result in reduced social support.

CONCLUSIONS

Our findings underscore patients' persistent experience of fatigue on PARPi, the impact of fatigue on multiple domains of functioning, and a lack of understanding of side effects resulting from oral maintenance treatments among patients' social networks. Our findings highlight the need for interventions to address treatment-related fatigue to limit the negative impacts of fatigue on ovarian cancer patients' well-being.

Measuring Quality of Life in Ovarian Cancer Clinical Trials-Can We Improve Objectivity and Cross Trial Comparisons?

Epithelial ovarian cancer (EOC) remains a lethal disease for the majority of women diagnosed with it worldwide. For the majority of patients, diagnosis occurs late, in the advanced setting. Disease-induced as well as treatment-related adverse events can negatively impact quality of life (QoL). Research to date has captured these data through use of patient-related outcomes (PROs) and, increasingly, has become an area of increased attention and focus in clinical trial reporting. QoL/PRO measurements in EOC clinical trials at different transition points in a patient's journey are increasingly being recognized by patients, clinicians and regulatory agencies as the key determinants of treatment benefit. Various context-specific PROs and PRO endpoints have been described for clinical trials in EOC. Standardized approaches and checklists for incorporating PRO endpoints in clinical trials have been proposed. In a real-world clinical practice setting, PRO/QoL measures, which are meaningful, valid, reliable, feasible and acceptable to patients and clinicians, need to be implemented and used. These may assist by serving as screening tools; helping with the identification of patient preferences to aid in decision making; improving patient-provider communication; facilitating shared decision making. Importantly, they may also improve quality of care through an increasingly patient-centered approach. Potential areas of future research include assessment of anxiety, depression and other mental health issues. In good prognostic groups, such as maintenance clinical trials, following patients beyond progression will capture possible downstream effects related to delaying the psychological trauma of relapse, symptoms due to disease progression and side-effects of subsequent chemotherapy. Identifying PRO endpoints in next-generation-targeted therapies (including immunotherapies) also warrants investigation.

Therapeutic options following second-line platinum-based chemotherapy in patients with recurrent ovarian cancer: Comparison of active surveillance and maintenance treatment

Most women with advanced ovarian cancer respond to initial treatment, consisting of surgical resection and ≈6 cycles of platinum-based chemotherapy. However, disease recurrence occurs in most patients, and subsequent therapies become necessary. Historically, close monitoring following treatment (active surveillance) was the only available option, as continued maintenance chemotherapy treatment led to increased toxicity without providing any meaningful clinical benefit. Recently, targeted therapy with the angiogenesis inhibitor bevacizumab and the poly(ADP-ribose) polymerase (PARP) inhibitors olaparib, niraparib, and rucaparib have demonstrated significant clinical benefits as maintenance treatment for recurrent disease. Despite consensus guidelines recommending their use, maintenance treatments are currently underutilized. Here, we review evidence from pivotal clinical trials of approved second-line maintenance treatments demonstrating efficacy in terms of progression-free survival and postprogression efficacy outcomes for patients with recurrent ovarian cancer. Adverse events frequently associated with bevacizumab include hypertension, proteinuria, and non-central nervous system bleeding, whereas PARP inhibitors are associated with nausea, vomiting, fatigue, and anemia. Patient-centered outcomes analyses show that PARP inhibitors provide significant benefits to patient health status, even when accounting for the toxicities associated with treatment. Many factors influence the selection of second-line maintenance treatment for patients with recurrent ovarian cancer, including the maintenance treatment received in the first-line setting. Overall, targeted maintenance treatment represents a new standard of care for patients with ovarian cancer, and we recommend that maintenance treatment should be offered to all eligible patients with recurrent ovarian cancer.

The effect of age on efficacy, safety and patient-centered outcomes with rucaparib: A post hoc exploratory analysis of ARIEL3, a phase 3, randomized, maintenance study in patients with recurrent ovarian carcinoma

BACKGROUND

In the phase 3 trial ARIEL3, maintenance treatment with the poly(ADP-ribose) polymerase (PARP) inhibitor rucaparib provided clinical benefit versus placebo for patients with recurrent, platinum-sensitive ovarian cancer. Here, we evaluate the impact of age on the clinical utility of rucaparib in ARIEL3.

METHODS

Patients with platinum-sensitive, recurrent ovarian carcinoma with ≥2 prior platinum-based chemotherapies who responded to their last platinum-based therapy were enrolled in ARIEL3 and randomized 2:1 to rucaparib 600 mg twice daily or placebo. Exploratory, post hoc analyses of progression-free survival (PFS), patient-centered outcomes (quality-adjusted PFS [QA-PFS] and quality-adjusted time without symptoms or toxicity [Q-TWiST]), and safety were conducted in three age subgroups (<65 years, 65-74 years, and ≥75 years).

RESULTS

Investigator-assessed PFS was significantly longer with rucaparib than placebo in patients aged <65 years (rucaparib n = 237 vs placebo n = 117; median, 11.1 vs 5.4 months; hazard ratio [HR]: 0.33 [95% confidence interval (95% CI) 0.25-0.43]; P < 0.0001) and 65-74 years (n = 113 vs n = 64; median, 8.3 vs 5.3 months; HR 0.43 [95% CI 0.29-0.63]; P < 0.0001) and numerically longer in patients aged ≥75 years (n = 25 vs n = 8; median, 9.2 vs 5.5 months; HR 0.47 [95% CI 0.16-1.35]; P = 0.1593). QA-PFS and Q-TWiST were significantly longer with rucaparib than placebo across all age subgroups. Safety of rucaparib was generally similar across the age subgroups.

CONCLUSIONS

Efficacy, patient-centered outcomes, and safety of rucaparib were similar between age subgroups, indicating that all eligible women with recurrent ovarian cancer should be offered this therapeutic option, irrespective of age. https://clinicaltrials.gov/ct2/show/NCT01968213.