CA-125 elimination rate constant K (KELIM) as a promising predictor of complete cytoreduction after neoadjuvant chemotherapy in advanced ovarian cancer patients: a retrospective study from two Chinese hospitals

BACKGROUND

The modeled CA-125 elimination constant K (KELIM) is a potential marker of tumor chemosensitivity in ovarian cancer patients treated with neoadjuvant chemotherapy (NACT) before interval surgery. The objective of this study was to externally validate the KELIM (rate of elimination of CA-125) score in patients with high-grade serous ovarian cancer (HGSC) undergoing NACT and explore its relation to the completeness of IDS and survival.

METHODS

The study was based on a retrospective cohort of 133 patients treated for advanced HGSC, International Federation of Gynecology and Obstetrics (FIGO) stages III-IV, with neoadjuvant chemotherapy, folllowed by interval surgery, in two centres in China. CA-125 concentrations at baseline and during neoadjuvant chemotherapy were collected. We used standardized (std) KELIM for subsequent analysis. Clinicopathologic parameters were collected, and Kaplan‒Meier survival analyses were performed for PFS and OS.

RESULTS

KELIM was an independent predictor of the probability of complete surgery and survival in our cohort. The median std KELIM score of patients with complete surgery was significantly higher than that of patients with incomplete IDS (1.20 vs. 0.71, P < 0.001). Multivariate analysis showed that a std KELIM score ≥0.925 was an independent predictive factor for achieving complete resection (OR = 5.480; 95% CI, 2.409-12.466, P < 0.001) and better PFS (HR = 0.544; 95% CI: 0.349-0.849, P = 0.007) and OS (HR = 0.484; 95% CI: 0.251-0.930, P = 0.030).

CONCLUSIONS

The tumor-primary tumor chemosensitivity, assessed by the modeled CA-125 KELIM, calculated during NACT, is a major parameter to consider for decision-making regarding IDS attempts and predicting patient survival.

Adverse events of antibody-drug conjugates on the ocular surface in cancer therapy

Antibody-drug conjugates consist of a monoclonal antibody attached to a cytotoxic therapeutic molecule by a connector. This association allows a highly specific therapy, which increases their effectiveness and decreases their potential toxicity. This new therapy emerged approximately 20 years ago; since then, numerous combinations have appeared in the field of treatment-related neoplasms as an alternative for patients who do not achieve good results with conventional treatment options. Adverse effects of these drugs on the ocular surface are frequent and varied. Their prevalence ranges from 20 to 90% depending on the drug and administration condition, probably due to multiple receptor-mediated factors or mechanisms not mediated by specific receptors, such as macropinocytosis. These adverse events can greatly limit patients' comfort; thus, the objectives of this article were, in the first place, to compile the information currently available on different types of adverse effects of antibody-drug conjugates on the ocular surface, including pathophysiology, prevalence, and treatment, and in second place, to contribute to the correct identification and management of these events, which will result in a lower rate of cessation of treatment, which is necessary for the survival of candidate patients.

New insights into the anticancer therapeutic potential of maytansine and its derivatives

Maytansine is a pharmacologically active 19-membered ansamacrolide derived from various medicinal plants and microorganisms. Among the most studied pharmacological activities of maytansine over the past few decades are anticancer and anti-bacterial effects. The anticancer mechanism of action is primarily mediated through interaction with the tubulin thereby inhibiting the assembly of microtubules. This ultimately leads to decreased stability of microtubule dynamics and cause cell cycle arrest, resulting in apoptosis. Despite its potent pharmacological effects, the therapeutic applications of maytansine in clinical medicine are quite limited due to its non-selective cytotoxicity. To overcome these limitations, several derivatives have been designed and developed mostly by modifying the parent structural skeleton of maytansine. These structural derivatives exhibit improved pharmacological activities as compared to maytansine. The present review provides a valuable insight into maytansine and its synthetic derivatives as anticancer agents.

Mirvetuximab Soravtansine in Platinum-Resistant Ovarian Cancer

Ovarian cancer is the second leading cause of death from gynecologic malignancies worldwide. Management of platinum-resistant disease is challenging and clinical outcomes with standard chemotherapy are poor. Over the past decades, significant efforts have been made to understand drug resistance and develop strategies to overcome treatment failure. Antibody drug conjugates (ADCs) are a rapidly growing class of oncologic therapeutics, which combine the ability to target tumor-specific antigens with the cytotoxic effects of chemotherapy. Mirvetuximab soravtansine is an ADC comprising an IgG1 monoclonal antibody against the folate receptor alpha (FRα) conjugated to the cytotoxic maytansinoid effector molecule DM4 that has shown promising clinical activity in patients with FR-α-positive ovarian cancer. This review summarizes current evidence of mirvetuximab soravtansine in platinum-resistant ovarian cancer, focusing on clinical activity, toxicity, and future directions.

Pegylated liposomal doxorubicin for relapsed epithelial ovarian cancer

BACKGROUND

Cancer of ovarian, fallopian tube and peritoneal origin, referred to collectively as ovarian cancer, is the eighth most common cancer in women and is often diagnosed at an advanced stage. Women with relapsed epithelial ovarian cancer (EOC) are less well and have a limited life expectancy, therefore maintaining quality of life with effective symptom control is an important aim of treatment. However, the unwanted effects of chemotherapy agents may be severe, and optimal treatment regimens are unclear. Pegylated liposomal doxorubicin (PLD), which contains a cytotoxic drug called doxorubicin hydrochloride, is one of several treatment modalities that may be considered for treatment of relapsed EOCs. This is an update of the original Cochrane Review which was published in Issue 7, 2013.

OBJECTIVES

To evaluate the efficacy and safety of PLD, with or without other anti-cancer drugs, in women with relapsed high grade epithelial ovarian cancer (EOC).

SEARCH METHODS

We searched CENTRAL, MEDLINE (via Ovid) and Embase (via Ovid) from 1990 to January 2022. We also searched online registers of clinical trials, abstracts of scientific meetings and reference lists of included studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that evaluated PLD in women diagnosed with relapsed epithelial ovarian cancer.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data to a pre-designed data collection form and assessed the risk of bias according to the Cochrane Handbook for Systematic Reviews of Interventions guidelines. Where possible, we pooled collected data in meta-analyses.

MAIN RESULTS

This is an update of a previous review with 12 additional studies, so this updated review includes a total of 26 RCTs with 8277 participants that evaluated the effects of PLD alone or in combination with other drugs in recurrent EOC: seven in platinum-sensitive disease (2872 participants); 11 in platinum-resistant disease (3246 participants); and eight that recruited individuals regardless of platinum sensitivity status (2079 participants). The certainty of the evidence was assessed for the three most clinically relevant comparisons out of eight comparisons identified in the included RCTs. Recurrent platinum-sensitive EOC PLD with conventional chemotherapy agent compared to alternative combination chemotherapy likely results in little to no difference in overall survival (OS) (hazard ratio (HR) 0.93, 95% confidence interval (CI) 0.83 to 1.04; 5 studies, 2006 participants; moderate-certainty evidence) but likely increases progression-free survival (PFS) (HR 0.81, 95% CI 0.74 to 0.89; 5 studies, 2006 participants; moderate-certainty evidence). The combination may slightly improve quality of life at three months post-randomisation, measured using European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30 (mean difference 4.80, 95% CI 0.92 to 8.68; 1 study, 608 participants; low-certainty evidence), but this may not represent a clinically meaningful difference. PLD in combination with another chemotherapy agent compared to alternative combination chemotherapy likely results in little to no difference in the rate of overall severe adverse events (grade ≥ 3) (risk ratio (RR) 1.11, 95% CI 0.95 to 1.30; 2 studies, 834 participants; moderate-certainty evidence). PLD with chemotherapy likely increases anaemia (grade ≥ 3) (RR 1.37, 95% CI 1.02 to 1.85; 5 studies, 1961 participants; moderate-certainty evidence). The evidence is very uncertain about the effect of PLD with conventional chemotherapy on hand-foot syndrome (HFS)(grade ≥ 3) (RR 4.01, 95% CI 1.00 to 16.01; 2 studies, 1028 participants; very low-certainty evidence) and neurological events (grade ≥ 3) (RR 0.38, 95% CI 0.20 to 0.74; 4 studies, 1900 participants; very low-certainty evidence). Recurrent platinum-resistant EOC PLD alone compared to another conventional chemotherapy likely results in little to no difference in OS (HR 0.96, 95% CI 0.77 to 1.19; 6 studies, 1995 participants; moderate-certainty evidence). The evidence is very uncertain about the effect of PLD on PFS (HR 0.94, 95% CI 0.85 to 1.04; 4 studies, 1803 participants; very low-certainty evidence), overall severe adverse events (grade ≥ 3) (RR ranged from 0.61 to 0.97; 2 studies, 964 participants; very low-certainty evidence), anaemia (grade ≥ 3) (RR ranged from 0.19 to 0.82; 5 studies, 1968 participants; very low-certainty evidence), HFS (grade ≥ 3) (RR ranged from 15.19 to 109.15; 6 studies, 2184 participants; very low-certainty evidence), and the rate of neurological events (grade ≥ 3)(RR ranged from 0.08 to 3.09; 3 studies, 1222 participants; very low-certainty evidence). PLD with conventional chemotherapy compared to PLD alone likely results in little to no difference in OS (HR 0.92, 95% CI 0.70 to 1.21; 1 study, 242 participants; moderate-certainty evidence) and it may result in little to no difference in PFS (HR 0.94, 95% CI 0.73 to 1.22; 2 studies, 353 participants; low-certainty evidence). The combination likely increases overall severe adverse events (grade ≥ 3) (RR 2.48, 95% CI 1.98 to 3.09; 1 study, 663 participants; moderate-certainty evidence) and anaemia (grade ≥ 3) (RR 2.38, 95% CI 1.46 to 3.87; 2 studies, 785 participants; moderate-certainty evidence), but likely results in a large reduction in HFS (grade ≥ 3) (RR 0.24, 95% CI 0.14 to 0.40; 2 studies, 785 participants; moderate-certainty evidence). It may result in little to no difference in neurological events (grade ≥ 3) (RR 1.40, 95% CI 0.85 to 2.31; 1 study, 663 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

In platinum-sensitive relapsed EOC, including PLD in a combination chemotherapy regimen probably makes little to no difference in OS compared to other combinations, but likely improves PFS. Choice of chemotherapy will therefore be guided by symptoms from previous chemotherapy and other patient considerations. Single-agent PLD remains a useful agent for platinum-resistant relapsed EOC and choice of agent at relapse will depend on patient factors, e.g. degree of bone marrow suppression or neurotoxicity from previous treatments. Adding another agent to PLD likely increases overall grade ≥ 3 adverse events with little to no improvement in survival outcomes. The limited evidence relating to PLD in combination with other agents in platinum-resistant relapsed EOC does not indicate a benefit, but there is some evidence of increased side effects.

Mirvetuximab Soravtansine: First Approval

Mirvetuximab soravtansine (mirvetuximab soravtansine-gynx; Elahere^™) is an antibody-drug conjugate (ADC), which is comprised of a folate receptor α (FRα) directed antibody conjugated to a microtubule inhibitor via a cleavable linker. The ADC is being developed by ImmunoGen for the treatment of FRα expressing cancers. In November 2022, mirvetuximab soravtansine was approved in the USA for the treatment of adult patients with FRα positive, platinum-resistant epithelial ovarian, fallopian tube or primary peritoneal cancer who have received 1-3 prior systemic treatment regimens. This article summarizes the milestones in the development of mirvetuximab soravtansine leading to this first approval.

Targeting NaPi2b in ovarian cancer

Novel biomarkers are needed to direct new treatments for ovarian cancer, a disease for which the standard of care remains heavily focused on platinum-based chemotherapy. Despite the success of PARP inhibitors, treatment options are limited, particularly in the platinum-resistant setting. NaPi2b is a cell surface sodium-dependent phosphate transporter that regulates phosphate homeostasis under normal physiological conditions and is a lineage marker that is expressed in select cancers, including ovarian, lung, thyroid, and breast cancers, with limited expression in normal tissues. Based on its increased expression in ovarian tumors, NaPi2b is a promising candidate to be studied as a biomarker for treatment and patient selection in ovarian cancer. In preclinical studies, the use of antibodies against NaPi2b showed that this protein can be exploited for tumor mapping and therapeutic targeting. Emerging data from phase 1 and 2 clinical trials in ovarian cancer have suggested that NaPi2b can be successfully detected in patient biopsy samples using immunohistochemistry, and the NaPi2b-targeting antibody-drug conjugate under evaluation appeared to elicit therapeutic responses. The aim of this review is to examine literature supporting NaPi2b as a novel biomarker for potential treatment and patient selection in ovarian cancer and to discuss the critical next steps and future analyses necessary to drive the study of this biomarker and therapeutic targeting forward.

Folate receptor alpha in ovarian cancer tissue and patient serum is associated with disease burden and treatment outcomes

BACKGROUND

Survival rates for ovarian cancer remain poor, and monitoring and prediction of therapeutic response may benefit from additional markers. Ovarian cancers frequently overexpress Folate Receptor alpha (FRα) and the soluble receptor (sFRα) is measurable in blood. Here we investigated sFRα as a potential biomarker.

METHODS

We evaluated sFRα longitudinally, before and during neo-adjuvant, adjuvant and palliative therapies, and tumour FRα expression status by immunohistrochemistry. The impact of free FRα on the efficacy of anti-FRα treatments was evaluated by an antibody-dependent cellular cytotoxicity assay.

RESULTS

Membrane and/or cytoplasmic FRα staining were observed in 52.7% tumours from 316 ovarian cancer patients with diverse histotypes. Circulating sFRα levels were significantly higher in patients, compared to healthy volunteers, specifically in patients sampled prior to neoadjuvant and palliative treatments. sFRα was associated with FRα cell membrane expression in the tumour. sFRα levels decreased alongside concurrent tumour burden in patients receiving standard therapies. High concentrations of sFRα partly reduced anti-FRα antibody tumour cell killing, an effect overcome by increased antibody doses.

CONCLUSIONS

sFRα may present a non-invasive marker for tumour FRα expression, with the potential for monitoring patient response to treatment. Larger, prospective studies should evaluate FRα for assessing disease burden and response to systemic treatments.

Cediranib in Combination with Olaparib in Patients without a Germline BRCA1/2 Mutation and with Recurrent Platinum-Resistant Ovarian Cancer: Phase IIb CONCERTO Trial

PURPOSE

The efficacy, safety, and tolerability of cediranib plus olaparib (cedi/ola) were investigated in patients with nongermline-BRCA-mutated (non-gBRCAm) platinum-resistant recurrent ovarian cancer.

PATIENTS AND METHODS

PARP inhibitor-naïve women aged ≥18 years with platinum-resistant non-gBRCAm ovarian cancer, ECOG performance status of 0-2, and ≥3 prior lines of therapy received cediranib 30 mg once daily plus olaparib 200 mg twice daily in this single-arm, multicenter, phase IIb trial. The primary endpoint was objective response rate (ORR) by independent central review (ICR) using RECIST 1.1. Progression-free survival (PFS), overall survival (OS), and safety and tolerability were also examined.

RESULTS

Sixty patients received cedi/ola, all of whom had confirmed non-gBRCAm status. Patients had received a median of four lines of chemotherapy; most (88.3%) had received prior bevacizumab. ORR by ICR was 15.3%, median PFS was 5.1 months, and median OS was 13.2 months. Forty-four (73.3%) patients reported a grade ≥3 adverse event (AE), with one patient experiencing a grade 5 AE (sepsis), considered unrelated to the study treatment. Dose interruptions, reductions, and discontinuations due to AEs occurred in 55.0%, 18.3%, and 18.3% of patients, respectively. Patients with high global loss of heterozygosity (gLOH) had ORR of 26.7% [4/15; 95% confidence interval (CI), 7.8-55.1], while ORR was 12.5% (4/32; 95% CI, 3.5-29.0) in the low gLOH group.

CONCLUSIONS

Clinical activity was shown for the cedi/ola combination in heavily pretreated, non-gBRCAm, platinum-resistant patients with ovarian cancer despite failing to meet the target ORR of 20%, highlighting a need for further biomarker studies.

Antibody drug conjugate: the "biological missile" for targeted cancer therapy

Antibody–drug conjugate (ADC) is typically composed of a monoclonal antibody (mAbs) covalently attached to a cytotoxic drug via a chemical linker. It combines both the advantages of highly specific targeting ability and highly potent killing effect to achieve accurate and efficient elimination of cancer cells, which has become one of the hotspots for the research and development of anticancer drugs. Since the first ADC, Mylotarg^® (gemtuzumab ozogamicin), was approved in 2000 by the US Food and Drug Administration (FDA), there have been 14 ADCs received market approval so far worldwide. Moreover, over 100 ADC candidates have been investigated in clinical stages at present. This kind of new anti-cancer drugs, known as “biological missiles”, is leading a new era of targeted cancer therapy. Herein, we conducted a review of the history and general mechanism of action of ADCs, and then briefly discussed the molecular aspects of key components of ADCs and the mechanisms by which these key factors influence the activities of ADCs. Moreover, we also reviewed the approved ADCs and other promising candidates in phase-3 clinical trials and discuss the current challenges and future perspectives for the development of next generations, which provide insights for the research and development of novel cancer therapeutics using ADCs.

Poly(ADP-ribose) polymerase (PARP) inhibitors for the treatment of ovarian cancer

BACKGROUND

Ovarian cancer is the sixth most common cancer in women world-wide. Epithelial ovarian cancer (EOC) is the most common; three-quarters of women present when disease has spread outside the pelvis (stage III or IV). Treatment consists of a combination of  surgery and platinum-based chemotherapy. Although initial responses to chemotherapy are good, most women with advanced disease will relapse. PARP (poly (ADP-ribose) polymerase) inhibitors (PARPi), are a type of anticancer treatment that works by preventing cancer cells from repairing DNA damage, especially in those with breast cancer susceptibility gene (BRCA) variants. PARPi offer a different mechanism of anticancer treatment from conventional chemotherapy.

OBJECTIVES

To determine the benefits and risks of poly (ADP-ribose) polymerase) inhibitors (PARPi) for the treatment of epithelial ovarian cancer (EOC).

SEARCH METHODS

We identified randomised controlled trials (RCTs) by searching the Cochrane Central Register of Controlled Trials (Central 2020, Issue 10), Cochrane Gynaecological Cancer Group Trial Register, MEDLINE (1990 to October 2020), Embase (1990 to October 2020), ongoing trials on www.controlled-trials.com/rct, www.clinicaltrials.gov, www.cancer.gov/clinicaltrials, the National Research Register (NRR), FDA database and pharmaceutical industry biomedical literature.

SELECTION CRITERIA

We included trials that randomised women with EOC to PARPi with no treatment, or PARPi versus conventional chemotherapy, or PARPi together with conventional chemotherapy versus conventional chemotherapy alone.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology. Two review authors independently assessed whether studies met the inclusion criteria. We contacted investigators for additional data. Outcomes included overall survival (OS), objective response rate (ORR), quality of life (QoL) and rate of adverse events.

MAIN RESULTS

We included 15 studies (6109 participants); four (3070 participants) with newly-diagnosed, advanced EOC and 11 (3039 participants) with recurrent EOC. The studies varied in types of comparisons and evaluated PARPi. Eight studies were judged as at low risk of bias in most of the domains. Quality of life data were generally poorly reported. Below we present six key comparisons.  The majority of participants had BRCA mutations, either in their tumour (sBRCAmut) and/or germline (gBRCAmut), or homologous recombination deficiencies (HRD) in their tumours. Newly diagnosed EOC Overall, four studies evaluated the effect of PARPi in newly-diagnosed, advanced EOC. Two compared PARPi with chemotherapy and chemotherapy alone. OS data were not reported. The combination of PARPi with chemotherapy may have little to no difference in progression-free survival (PFS) (two studies, 1564 participants; hazard ratio (HR) 0.82, 95% confidence interval (CI 0).49 to 1.38; very low-certainty evidence)(no evidence of disease progression at 12 months' 63% with PARPi versus 69% for placebo).  PARPi with chemotherapy likely increases any severe adverse event (SevAE) (grade 3 or higher) slightly (45%) compared with chemotherapy alone (51%) (two studies, 1549 participants, risk ratio (RR) 1.13, 95% CI 1.07 to 1.20; high-certainty evidence). PARPi combined with chemotherapy compared with chemotherapy alone likely results in little to no difference in the QoL (one study; 744 participants, MD 1.56 95% CI -0.42 to 3.54; moderate-certainty evidence).  Two studies compared PARPi monotherapy with placebo as maintenance after first-line chemotherapy in newly diagnosed EOC. PARPi probably results in little to no difference in OS (two studies, 1124 participants; HR 0.81, 95%CI 0.59 to 1.13; moderate-certainty evidence) (alive at 12 months 68% with PARPi versus 62% for placebo). However, PARPi may increase PFS (two studies, 1124 participants; HR 0.42, 95% CI 0.19 to 0.92; low-certainty evidence) (no evidence of disease progression at 12 months' 55% with PARPi versus 24% for placebo). There may be an increase in the risk of experiencing any SevAE (grade 3 or higher) with PARPi (54%) compared with placebo (19%)(two studies, 1118 participants, RR 2.87, 95% CI 1.65 to 4.99; very low-certainty evidence), but the evidence is very uncertain. There is probably a slight reduction in QoL with PARPi, although this may not be clinically significant (one study, 362 participants; MD -3.00, 95%CI -4.48 to -1.52; moderate-certainty evidence).  Recurrent, platinum-sensitive EOC Overall, 10 studies evaluated the effect of PARPi in recurrent platinum-sensitive EOC. Three studies compared PARPi monotherapy with chemotherapy alone. PARPi may result in little to no difference in OS (two studies, 331 participants; HR 0.95, 95%CI 0.62 to 1.47; low-certainty evidence) (percentage alive at 36 months 18% with PARPi versus 17% for placebo). Evidence is very uncertain about the effect of PARPi on PFS (three studies, 739 participants; HR 0.88, 95%CI 0.56 to 1.38; very low-certainty evidence)(no evidence of disease progression at 12 months 26% with PARPi versus 22% for placebo). There may be little to no difference in rates of any SevAE (grade 3 or higher) with PARPi (50%) than chemotherapy alone (47%) (one study, 254 participants; RR 1.06, 95%CI 0.80 to 1.39; low-certainty evidence). Four studies compared PARPi monotherapy as maintenance with placebo. PARPi may result in little to no difference in OS (two studies, 560 participants; HR 0.88, 95%CI 0.65 to 1.20; moderate-certainty evidence)(percentage alive at 36 months 21% with PARPi versus 17% for placebo). However, evidence suggests that PARPi as maintenance therapy results in a large PFS (four studies, 1677 participants; HR 0.34, 95% CI 0.28 to 0.42; high-certainty evidence)(no evidence of disease progression at 12 months 37% with PARPi versus 5.5% for placebo). PARPi maintenance therapy may result in a large increase in any SevAE (51%) (grade 3 or higher) than placebo (19%)(four studies, 1665 participants, RR 2.62, 95%CI 1.85 to 3.72; low-certainty evidence). PARPi compared with chemotherapy may result in little or no change in QoL (one study, 229 participants, MD 1.20, 95%CI -1.75 to 4.16; low-certainty evidence). Recurrent, platinum-resistant EOC Two studies compared PARPi with chemotherapy. The certainty of evidence in both studies was graded as very low. Overall, there was minimal information on the QoL and adverse events.

AUTHORS' CONCLUSIONS

PARPi maintenance treatment after chemotherapy may improve PFS in women with newly-diagnosed and recurrent platinum-sensitive EOC; there may be little to no effect on OS, although OS data are immature. Overall, this is likely at the expense of an increase in SevAE. It is  disappointing that data on quality of life outcomes  are relatively sparse. More research is needed to determine whether PARPi have a role to play in platinum-resistant disease.

Prise en charge médicale de la récidive du cancer épithélial de l'ovaire: Medical management of recurrent epithelial ovarian cancer

The panel of therapeutic options available for medical treatment of relapsed ovarian cancer increased over the last years. In late, platinum-sensitive relapse, standard treatment remains platinum-based polychemotherapy. The choice between bevacizumab added to chemotherapy followed by maintenance and inhibitors of poly-(ADP-riboses) polymerases (PARPi) after response to platinum-based therapy should be discussed, taking into account prior treatment, contraindications, and disease characteristics (biology, symptoms…). The addition of bevacizumab at first platinum-sensitive relapse can be considered if it has not been administered in first line, and it is optional (rechallenge) if previously administered (but without Marketing Authorization in this setting). PARPi are indicated for maintenance therapy after response to platinum-based chemotherapy (whatever the treatment line), regardless of BRCA mutational status, in case of no prior administration. Early relapses are associated with poor prognosis and therapeutic options are more limited. They are treated by monochemotherapy without platinum agents, associated with bevacizumab if not administered previously. Beyond first early relapse, there is no standard and inclusion in a clinical trial should be proposed if possible. Several clinical studies assessing associations of immunotherapy and chemotherapy and/or antiangiogenic drugs and/or targeted therapies (such as PARPi) are ongoing in early or late relapse.

Newly developed dual topoisomerase inhibitor P8-D6 is highly active in ovarian cancer

Background:

Ovarian cancer (OvCa) constitutes a rare and highly aggressive malignancy and is one of the most lethal of all gynaecologic neoplasms. Due to chemotherapy resistance and treatment limitations because of side effects, OvCa is still not sufficiently treatable. Hence, new drugs for OvCa therapy such as P8-D6 with promising antitumour properties have a high clinical need. The benzo[c]phenanthridine P8-D6 is an effective inductor of apoptosis by acting as a dual topoisomerase I/II inhibitor.

Methods:

In the present study, the effectiveness of P8-D6 on OvCa was investigated in vitro. In various OvCa cell lines and ex vivo primary cells, the apoptosis induction compared with standard therapeutic agents was determined in two-dimensional monolayers. Expanded by three-dimensional and co-culture, the P8-D6 treated cells were examined for changes in cytotoxicity, apoptosis rate and membrane integrity via scanning electron microscopy (SEM). Likewise, the effects of P8-D6 on non-cancer human ovarian surface epithelial cells and primary human hepatocytes were determined.

Results:

This study shows a significant P8-D6-induced increase in apoptosis and cytotoxicity in OvCa cells which surpasses the efficacy of well-established drugs like cisplatin or the topoisomerase inhibitors etoposide and topotecan. Non-cancer cells were affected only slightly by P8-D6. Moreover, no hepatotoxic effect in in vitro studies was detected.

Conclusion:

P8-D6 is a strong and rapid inductor of apoptosis and might be a novel treatment option for OvCa therapy.

Revisiting antibody-drug conjugates and their predictive biomarkers in platinum-resistant ovarian cancer

Until to date, platinum derived drugs are still the backbone of treating ovarian cancer (OC). Most patients treated with platinum-based chemotherapy develop resistance during the course of their management. The treatment of platinum-resistant ovarian cancer (PROC) is challenging. Few therapeutic options are available for patients with this aggressive disease. Besides, there are liminal advances regarding new anticancer drugs as well as validated predictive biomarkers of clinical outcomes in this setting. The enrollment of PROC patients in interventional studies is limited as compared to newly launched clinical trials for platinum-sensitive OC. Enthusiastically, the emergence of antibody-drug conjugates (ADCs) has provided promising findings for further clinical development in PROC. ADCs have the advantage to selectively deliver cytotoxic drugs to cancer cells expressing several of antigens using specific monoclonal antibodies based on the concept of immune bioconjugation. This innovative class of therapeutics showed encouraging early signs of clinical efficacy in PROC particularly mirvetuximab soravtansine that has been successfully introduced into three randomized and controlled phase III studies. In this review, the evidence from clinical trials supporting the development of ADCs targeting folate receptor alpha, sodium-dependent phosphate transporter 2B, dipeptidase 3, mesothelin, mucin 16, and tissue factor using various cytotoxic payloads in PROC is reviewed.

Nivolumab Versus Gemcitabine or Pegylated Liposomal Doxorubicin for Patients With Platinum-Resistant Ovarian Cancer: Open-Label, Randomized Trial in Japan (NINJA)

PURPOSE

This phase III, multicenter, randomized, open-label study investigated the efficacy and safety of nivolumab versus chemotherapy (gemcitabine [GEM] or pegylated liposomal doxorubicin [PLD]) in patients with platinum-resistant ovarian cancer.

MATERIALS AND METHODS

Eligible patients had platinum-resistant epithelial ovarian cancer, received ≤ 1 regimen after diagnosis of resistance, and had an Eastern Cooperative Oncology Group performance score of ≤ 1. Patients were randomly assigned 1:1 to nivolumab (240 mg once every 2 weeks [as one cycle]) or chemotherapy (GEM 1000 mg/m2 for 30 minutes [once on days 1, 8, and 15] followed by a week's rest [as one cycle], or PLD 50 mg/m2 once every 4 weeks [as one cycle]). The primary outcome was overall survival (OS). Secondary outcomes included progression-free survival (PFS), overall response rate, duration of response, and safety.

RESULTS

Patients (n = 316) were randomly assigned to nivolumab (n = 157) or GEM or PLD (n = 159) between October 2015 and December 2017. Median OS was 10.1 (95% CI, 8.3 to 14.1) and 12.1 (95% CI, 9.3 to 15.3) months with nivolumab and GEM or PLD, respectively (hazard ratio, 1.0; 95% CI, 0.8 to 1.3; P = .808). Median PFS was 2.0 (95% CI, 1.9 to 2.2) and 3.8 (95% CI, 3.6 to 4.2) months with nivolumab and GEM or PLD, respectively (hazard ratio, 1.5; 95% CI, 1.2 to 1.9; P = .002). There was no statistical difference in overall response rate between groups (7.6% v 13.2%; odds ratio, 0.6; 95% CI, 0.2 to 1.3; P = .191). Median duration of response was numerically longer with nivolumab than GEM or PLD (18.7 v 7.4 months). Fewer treatment-related adverse events were observed with nivolumab versus GEM or PLD (61.5% v 98.1%), with no additional or new safety risks.

CONCLUSION

Although well-tolerated, nivolumab did not improve OS and showed worse PFS compared with GEM or PLD in patients with platinum-resistant ovarian cancer.

Advances in the treatment of platinum resistant epithelial ovarian cancer: an update on standard and experimental therapies

Introduction: Platinum-resistant ovarian cancer (PROC) is broadly defined as disease recurrence within 6 months of completing platinum-based chemotherapy, either in the primary or recurrent setting. Although there is significant heterogeneity, PROC is generally associated with poor outcomes and low response rates to standard chemotherapy. There have been novel developments in therapeutics for PROC based on biomarkers and a more nuanced understanding of DNA repair and immunologic pathways.Areas covered: This review provides a summary of standard of care and experimental therapies for patients with PROC. Recent advances in our understanding of the DNA damage response and immunobiology of ovarian cancer have paved the way for single agent and combinatorial strategies involving PARP inhibitors, cell cycle checkpoint inhibitors, and immune checkpoint inhibitors to overcome PARP resistance, capitalize on high replication stress, and promote effective anti-tumor immunity, respectively. Furthermore, novel agents including antibody drug conjugates, bispecific antibodies, and recombinant fusion proteins show promise as experimental treatment options.Expert opinion: Standard and experimental treatment options available to patients with PROC have expanded. Testing for BRCA status, tumor mutational burden, and mismatch repair deficiency is recommended to guide therapy. Clinical trial participation is strongly encouraged with a focus on biomarker-driven trials targeting specific patient populations. Novel approaches such as ADCs, bispecific antibodies, targeting the GAS6/AXL and Notch pathways, and oncolytic virotherapy show considerable promise as emerging therapies.

Progress in Gynecologic Cancers with Antibody Drug Conjugates

PURPOSE OF REVIEW

This article provides a comprehensive review of antibody-drug conjugates (ADCs) under investigation in gynecologic cancers. The structure and function of ADCs are reviewed with a focus on clinical benefit as well as toxicity profiles.

RECENT FINDINGS

Several ADCs with various target antigens have been investigated in ovarian, cervical, and endometrial cancer. ADCs have consistently demonstrated favorable safety/tolerability profiles both as monotherapy and in combination therapy. In ovarian cancer, response rates have ranged from 9 to 46% for monotherapy with response rates as high as 83% in combination therapy. In patients with cervical cancer with progressive disease despite doublet therapy and bevacizumab, response rates as high as 24% have been observed. ADCs represent a rapidly evolving field of targeted therapy which have demonstrated notable clinical benefit both as monotherapy but also in combination therapy with an overall favorable toxicity profile. With continued refinement of the target biomarkers utilized, improved clinical benefit is likely to be observed.

First-in-Human Phase 1 Study of MORAb-202, an Antibody-Drug Conjugate Comprising Farletuzumab Linked to Eribulin Mesylate, in Patients with Folate Receptor-α-Positive Advanced Solid Tumors

PURPOSE

MORAb-202, an antibody-drug conjugate containing farletuzumab and eribulin with a cathepsin-B cleavable linker, targets folate receptor α (FRα)-expressing tumor cells. The primary objective of this first-in-human study was to evaluate the safety and tolerability of MORAb-202 in patients with solid tumors.

PATIENTS AND METHODS

Patients ≥20 years with adequate organ function and FRα-positive solid tumors who failed to respond to standard therapy were eligible. Patients received MORAb-202 intravenously at doses of 0.3 to 1.2 mg/kg once every three weeks. Endpoints included dose-limiting toxicities, safety, tumor responses, pharmacokinetics, and pharmacodynamics.

TRIAL REGISTRATION NUMBER

NCT03386942 (ClinicalTrials.gov).

RESULTS

Between November 28, 2017 and June 4, 2019, 22 patients (median age, 58.0 years) with advanced solid tumors were enrolled. Treatment-emergent adverse events occurred in 21 (95%) patients, with leukopenia and neutropenia in 10 (45%) patients each. One patient (0.9 mg/kg cohort) experienced two grade 3 dose-limiting toxicities: serum alanine aminotransferase and γ-glutamyl transferase increases. Following review by an independent adjudication committee, grade 1/2 interstitial lung disease thought to be related to MORAb-202 was identified in five (23%) patients. Complete response, partial response, and stable disease were observed in one, nine, and eight patients, respectively. The normalized predose serum FRα tended to be positively correlated with the maximum tumor shrinkage (R ² = 0.2379; P = 0.0291).

CONCLUSIONS

The MTD of MORAb-202 was not reached. MORAb-202 demonstrated promising antitumor activity in FRα-positive solid tumors and was generally well-tolerated at the tested doses. Further investigations are required to establish appropriate dosage and clinical utility of MORAb-202.

Ovarian cancer: new strategies and emerging targets for the treatment of patients with advanced disease

Recently approved therapies have contributed to a significant progress in the management of ovarian cancer; yet, more options are needed to further improve outcomes in patients with advanced disease. Here we review the rationale and ongoing clinical trials of novel combination strategies involving chemotherapy, poly ADP ribose polymerase, programmed death 1 (PD-1)/PD-ligand 1 immune checkpoint and/or vascular endothelial growth factor receptor inhibitors. Further, we discuss novel agents aimed at targets associated with ovarian cancer growth or progression that are emerging as potential new treatment approaches. Among them, agents targeted to folate receptor α, tissue factor, and protein kinase-mediated pathways (WEE1 kinase, phosphatidylinositol-3 kinase α, cell cycle checkpoint kinase 1/2, ATR kinase) are currently in clinical development as mono- or combination therapies. If successful, findings from these extensive development efforts may further transform treatment of patients with advanced ovarian cancer.

Antibody-drug conjugates in solid tumors: a look into novel targets

Antibody-drug conjugates (ADCs) are a relatively new class of anticancer agents designed to merge the selectivity of monoclonal antibodies with cell killing properties of chemotherapy. They are commonly described as the "Trojan Horses" of therapeutic armamentarium, because of their capability of directly conveying cytotoxic drug (payloads) into the tumor space, thus transforming chemotherapy into a targeted agent. Three novel ADCs have been recently approved, i.e., trastuzumab deruxtecan, sacituzumab govitecan and enfortumab vedotin, respectively, targeting HER2, Trop2 and Nectin4. Thanks to progressive advances in engineering technologies these drugs rely on, the spectrum of diseases sensitive to these drugs as well as their indications are in continuous expansion. Several novel ADCs are under evaluation, exploring new potential targets along with innovative payloads. This review aims at providing a summary of the technology behind these compounds and at presenting the latest ADCs approved in solid tumors, as well as at describing novel targets for ADCs under investigation and new strategies to optimize their efficacy in solid tumors.

Co-administered antibody improves penetration of antibody-dye conjugate into human cancers with implications for antibody-drug conjugates

Poor tissue penetration remains a major challenge for antibody-based therapeutics of solid tumors, but proper dosing can improve the tissue penetration and thus therapeutic efficacy of these biologics. Due to dose-limiting toxicity of the small molecule payload, antibody-drug conjugates (ADCs) are administered at a much lower dose than their parent antibodies, which further reduces tissue penetration. We conducted an early-phase clinical trial (NCT02415881) and previously reported the safety of an antibody-dye conjugate (panitumumab-IRDye800CW) as primary outcome. Here, we report a retrospective exploratory analysis of the trial to evaluate whether co-administration of an unconjugated antibody could improve the intratumoral distribution of the antibody-dye conjugate in patients. By measuring the multiscale distribution of the antibody-dye conjugate, this study demonstrates improved microscopic antibody distribution without increasing uptake (toxicity) in healthy tissue when co-administered with the parent antibody, supporting further clinical investigation of the co-administration dosing strategy to improve the tumor penetration of ADCs.

Further Understanding of High-Grade Serous Ovarian Carcinogenesis: Potential Therapeutic Targets

High-grade serous ovarian carcinoma (HGSOC) is the most common type of ovarian cancer and the most lethal gynecologic malignancy due to advanced stage at presentation. Recent years have witnessed progress in the therapy of HGSOC with the introduction of PARP (poly-adenosine diphosphate ribose polymerase) inhibitors and the anti-angiogenic monoclonal antibody bevacizumab to the backbone of chemotherapy or as maintenance therapy after chemotherapy. The improved molecular understanding of ovarian cancer pathogenesis, which has brought these therapies into the clinic, aspires to extend the boundaries of therapies through elucidation of other molecular aspects of ovarian carcinogenesis. This accumulating knowledge has started to be translated to additional targeted therapies that are in various stages of development. These include inhibitors of the function of other proteins involved in homologous recombination deficiency (HRD), such as WEE1 kinase, ATM/ATR kinases and CDK12 inhibitors. Despite disappointing results with immune checkpoint inhibitors monotherapy, harnessing the immune system in HGSOC with combination therapies that promote antigen production and immune cell activation is an avenue being explored. This paper examines arising HGSOC therapies based on molecular understanding of pathogenesis.

A phase II study of Mirvetuximab Soravtansine in triple-negative breast cancer

Folate receptor alpha (FRα) has been reported to be expressed in up to 80% of triple-negative breast cancers (TNBC) with limited expression in normal tissues, making it a promising therapeutic target. Mirvetuximab soravtansine (mirvetuximab-s) is an antibody drug conjugate which has shown promise in the treatment of FRα-positive solid tumors in early phase clinical trials. Herein, are the results of the first prospective phase II trial evaluating mirvetuximab-s in metastatic TNBC. Patients with advanced, FRα-positive TNBC were enrolled on this study. Mirvetuximab-s was administered at a dose of 6.0 mg/kg every 3 weeks. 96 patients with advanced TNBC consented for screening. FRα staining was performed on tumor tissue obtained from 80 patients. The rate of FRα positivity by immunohistochemistry was 10.0% (8/80). Two patients were treated on study, with best overall responses of stable disease in one and progressive disease in the other. Adverse events were consistent with earlier studies. The study was terminated early due to the low rate of FRα positivity in the screened patient population and lack of disease response in the two patients treated. The observed rate of FRα positivity was considerably lower than previously reported and none of the patients had a partial or complete response. Treatment with mirvetuximab-s should only be further explored in TNBC if an alternate biomarker strategy is developed for patient selection on the basis of additional preclinical data.

Antibody-Drug Conjugates: A Promising Novel Therapy for the Treatment of Ovarian Cancer

Antibody-drug conjugates (ADCs) represent a novel and promising therapeutic strategy for the treatment of cancer patients. ADCs target antigens highly expressed on the membrane surface of tumor cells to selectively deliver a cytotoxic drug. Ovarian tumors differentially express tumor-specific antigens, which can be used to guide ADCs. This strategy allows for optimizing tumor targeting while minimizing systemic toxicity compared to classical chemotherapeutic agents. ADCs can be improved by using a cleavable linker allowing the delivery of the toxic payload in surrounding cells not expressing the target protein, therefore acting on heterogeneous tumors with different cell populations. Currently, more than 15 ADCs are under preclinical investigation in ovarian cancer, and some of them have already been tested in early-phase clinical trials with promising results. In this review, we summarize the mechanism of action and the toxicity profile of ADCs and discuss the latest preclinical discoveries and forthcoming applications in ovarian cancer.

Patient Selection Strategies to Maximize Therapeutic Index of Antibody-Drug Conjugates: Prior Approaches and Future Directions

Antibody-drug conjugates (ADC) are targeted agents that have shown promise in treating cancer. A central challenge in development of ADCs is the relatively narrow therapeutic index observed in clinical studies. Patient selection strategies based on expression of the target in tumors have the potential to maximize benefit and provide the best chance of clinical success; however, implementation of biomarker-driven trials can be difficult both practically and scientifically. We conducted a survey of recent clinical experience from early-phase ADC trials completed between 2000 and 2019 to evaluate the different approaches to patient selection currently being used and assess whether there is evidence that target expression is associated with clinical activity. Our analysis of patient selection strategies indicates that optimal trial design for early-stage trials should be based on multiple factors, including prevalence and heterogeneity of target expression among intent-to-treat patients, as well as biological factors influencing expression of cell surface and soluble target. To ensure a high probability of success, early implementation of patient selection strategies centered around target expression are pivotal to development of ADCs. In this review, we propose a strategic approach that can be applied for optimization of trial design.

Exploiting the folate receptor α in oncology

Folate receptor α (FRα) came into focus as an anticancer target many decades after the successful development of drugs targeting intracellular folate metabolism, such as methotrexate and pemetrexed. Binding to FRα is one of several methods by which folate is taken up by cells; however, this receptor is an attractive anticancer drug target owing to the overexpression of FRα in a range of solid tumours, including ovarian, lung and breast cancers. Furthermore, using FRα to better localize effective anticancer therapies to their target tumours using platforms such as antibody-drug conjugates, small-molecule drug conjugates, radioimmunoconjugates and, more recently, chimeric antigen receptor T cells could further improve the outcomes of patients with FRα-overexpressing cancers. FRα can also be harnessed for predictive biomarker research. Moreover, imaging FRα radiologically or in real time during surgery can lead to improved functional imaging and surgical outcomes, respectively. In this Review, we describe the current status of research into FRα in cancer, including data from several late-phase clinical trials involving FRα-targeted therapies, and the use of new technologies to develop FRα-targeted agents with improved therapeutic indices.

European society of medical oncology (ESMO) 2019 meeting report features practice changing data in gynecologic malignancies

Multiple practice changing studies were presented at the 2019 ESMO Congress in Barcelona, Spain. The ovarian cancer studies presented at the Presidential session will likely refine and redefine the initial treatment of ovarian cancer. Other compelling trial data in ovarian, uterine and cervical cancer were also unveiled. The key oral abstracts from this meeting are summarized in this meeting report.