Exploring and comparing adverse events between PARP inhibitors

An overview of compound properties, multiparameter optimization, and computational drug design methods for PARP-1 inhibitor drugs

Breast cancer treatment with PARP-1 inhibitors remains challenging due to emerging toxicities, drug resistance, and unaffordable costs of treatment options. How do we invent strategies to design better anti-cancer drugs? A part of the answer is in optimized compound properties, desirability functions, and modern computational drug design methods that drive selectivity and toxicity and have not been reviewed for PARP-1 inhibitors. Nonetheless, comparisons of these compound properties for PARP-1 inhibitors are not available in the literature. In this review, we analyze the physchem, PKPD space to identify inherent desirability functions characteristic of approved drugs that can be valuable for the design of better candidates. Recent literature utilizing ligand, structure-based drug design strategies and matched molecular pair analysis (MMPA) for the discovery of novel PARP-1 inhibitors are also reviewed. Thus, this perspective provides valuable insights into the medchem and multiparameter optimization of PARP-1 inhibitors that might be useful to other medicinal chemists.

Major adverse cardiac events and cardiovascular toxicity with PARP inhibitors-based therapy for solid tumors: a systematic review and safety meta-analysis

BACKGROUND

Poly(ADP-ribose) polymerase (PARP) inhibitors (PARPi) provided significant antitumor activity in various tumors, mainly carrying deleterious mutations of BRCA1/BRCA2 genes. Only few data are available regarding the cardiac and vascular safety profile of this drug class. We carried out a meta-analysis for assessing the incidence and relative risk (RR) of major adverse cardiovascular events (MACEs), hypertension, and thromboembolic events in patients with solid tumors treated with PARPi-based therapy.

METHODS

Prospective studies were identified by searching the Medline/PubMed, Cochrane Library, and ASCO Meeting abstracts. Data extraction was conducted according to the Preferred Reporting Items for Systematic review and Meta-Analyses (PRISMA) statement. Combined odds ratios (ORs), RRs, and 95% confidence intervals (CIs) were calculated using fixed- or random-effects methods, depending on studies heterogeneity. RevMan software for meta-analysis (v.5.2.3) was used to carry out statistical analyses.

RESULTS

Thirty-two studies were selected for the final analysis. The incidence of PARPi-related MACEs of any and high grade was 5.0% and 0.9%, respectively, compared with 3.6% and 0.9% in the control arms, corresponding to a significant increased risk of MACEs of any grade (Peto OR 1.62; P = 0.0009) but not of high grade (P = 0.49). The incidence of hypertension of any grade and high grade was 17.5% and 6.0% with PARPi, respectively, compared with 12.6% and 4.4% in the controls. Treatment with PARPi significantly increased the risk of hypertension of any grade (random-effects, RR = 1.53; P = 0.03) but not of high grade (random-effects, RR = 1.47; P = 0.09) compared with controls. Finally, PARPi-based therapies significantly increased the risk of thromboembolic events of any grade (Peto OR = 1.49, P = 0.004) and not of high grade (Peto OR = 1.31; P = 0.13) compared with controls.

CONCLUSIONS

PARPi-based therapy is associated with a significantly increased risk of MACEs, hypertension, and thromboembolic events of any grade compared with controls. The lack of a significant increased risk of high-grade events together with the absolute low incidence of these adverse events led not to consider routine cardiovascular monitoring as recommended in asymptomatic patients.

Established and Emerging Cancer Therapies and Cardiovascular System: Focus on Hypertension-Mechanisms and Mitigation

Cardiovascular disease and cancer are 2 of the leading causes of death worldwide. Although improvements in outcomes have been noted for both disease entities, the success of cancer therapies has come at the cost of at times very impactful adverse events such as cardiovascular events. Hypertension has been noted as both, a side effect as well as a risk factor for the cardiotoxicity of cancer therapies. Some of these dynamics are in keeping with the role of hypertension as a cardiovascular risk factor not only for heart failure, but also for the development of coronary and cerebrovascular disease, and kidney disease and its association with a higher morbidity and mortality overall. Other aspects such as the molecular mechanisms underlying the amplification of acute and long-term cardiotoxicity risk of anthracyclines and increase in blood pressure with various cancer therapeutics remain to be elucidated. In this review, we cover the latest clinical data regarding the risk of hypertension across a spectrum of novel anticancer therapies as well as the underlying known or postulated pathophysiological mechanisms. Furthermore, we review the acute and long-term implications for the amplification of the development of cardiotoxicity with drugs not commonly associated with hypertension such as anthracyclines. An outline of management strategies, including pharmacological and lifestyle interventions as well as models of care aimed to facilitate early detection and more timely management of hypertension in patients with cancer and survivors concludes this review, which overall aims to improve both cardiovascular and cancer-specific outcomes.

cRGD-targeted heparin nanoparticles for effective dual drug treatment of cisplatin-resistant ovarian cancer

Resistance to the chemotherapeutic agent cisplatin (DDP) is the primary reason for invalid chemotherapy of ovarian cancer. Given the complex mechanisms underlying chemo-resistance, the design of combination therapies based on blocking multiple mechanisms is a rationale to synergistically elevate therapeutic effect for effectively overcoming cancer chemo-resistance. Herein, we demonstrated a multifunctional nanoparticle (DDP-Ola@HR), which could simultaneously co-deliver DDP and Olaparib (Ola, DNA damage repair inhibitor) using targeted ligand cRGD peptide modified with heparin (HR) as nanocarrier, enabling the concurrent tackling of multiple resistance mechanisms to effectively inhibit the growth and metastasis of DDP-resistant ovarian cancer. In combination strategy, heparin could suppress the function of multidrug resistance-associated protein 2 (MRP2) and P-glycoprotein (P-gp) to promote the intracellular accumulation of DDP and Ola by specifically binding with heparanase (HPSE) to down-regulate PI3K/AKT/mTOR signaling pathway, and simultaneously served as a carrier combined with Ola to synergistically enhance the anti-proliferation ability of DDP for resistant ovarian cancer, thus achieving great therapeutic efficacy. Our DDP-Ola@HR could provide a simple and multifunctional combination strategy to trigger an anticipated cascading effect, thus effectively overcoming the chemo-resistance of ovarian cancer.

Older but Stronger: Development of Platinum-Based Antitumor Agents and Research Advances in Tumor Immunity

Platinum (Pt) drugs have developed rapidly in clinical applications because of their broad and highly effective antitumor effects. In recent years, with the rapid development of immunotherapy, Pt-based antitumor agents have gained new challenges and opportunities. Since the discovery of their pharmacological effects in immunotherapy and tumor microenvironment regulation, research into Pt drugs has progressed to multi-ligand and multi-functional Pt precursors and their own shortcomings have been further highlighted. With the development of antitumor immunotherapy and the rise of combination therapy, the development of Pt-based drugs has started to move in the direction of multi-targeting, nanocarrier modification, immunotherapy and photodynamic therapy. In this paper, we first overview the recent applications of Pt-based drugs in antitumor inorganic chemistry, with a focus on summarizing the application of Pt-based drugs and their precursors in the anticancer immune response. The paper also provides a reasonable outlook on the future development of Pt-based drugs from the chemical and immunological perspectives, relying on the existing content and problems of Pt-based drug development. On the basis of the gathered information, joint multidisciplinary programs on implementing comprehensive immune analyses for the future development of novel anticancer metal compounds should be initiated.

Combining targeted DNA repair inhibition and immune-oncology approaches for enhanced tumor control

Targeted therapy and immunotherapy have revolutionized cancer treatment. However, the ability of cancer to evade the immune system remains a major barrier for effective treatment. Related to this, several targeted DNA-damage response inhibitors (DDRis) are being tested in the clinic and have been shown to potentiate anti-tumor immune responses. Seminal studies have shown that these agents are highly effective in a pan-cancer class of tumors with genetic defects in key DNA repair genes such as BRCA1/2, BRCA-related genes, ataxia telangiectasia mutated (ATM), and others. Here, we review the molecular consequences of targeted DDR inhibition, from tumor cell death to increased engagement of the anti-tumor immune response. Additionally, we discuss mechanistic and clinical rationale for pairing targeted DDRis with immunotherapy for enhanced tumor control. We also review biomarkers for patient selection and promising new immunotherapy approaches poised to form the foundation of next-generation DDRi and immunotherapy combinations.

Tolerance of Olaparib in a Patient With Unresectable Serous Gynecologic Cancer and End-Stage Renal Disease

Poly (adenosine diphosphate-ribose) polymerase enzyme (PARP) inhibitors have risen in popularity for the treatment of gynecologic cancers, largely due to an expansion of applications with the discovery of more genetic mutations that manifest as homologous recombination deficiency. PARP inhibitors further represent an appealing management option as oral maintenance or monotherapy. While dose adjustments exist for mild kidney dysfunction, little is published about the use of PARP inhibitors in patients with severe renal dysfunction. We present a case of advanced, serous gynecologic cancer in a patient who was ineligible for surgery due to cardiac and renal comorbidities and treated with olaparib for nine months without direct adverse effects, despite a paucity of literature supporting the use or dosing of olaparib in patients requiring dialysis. Further studies are needed to better establish the safety, efficacy, and appropriate dose modification for patients with end-stage renal disease.

Ovarian, Uterine, and Vulvovaginal Cancers: Screening, Treatment Overview, and Prognosis

Ovarian, uterine, and vulvovaginal cancers affect approximately 96,000 women per year in the United States, resulting in approximately 29,000 deaths annually. Routine screening protocols do not detect these malignancies; thus, the recognition of risk factors and evaluation of worrisome symptoms are essential for early detection and improved prognoses. Treatment is managed by gynecologic oncologists, and often involves a combination of surgery, chemotherapy, and possible radiation treatments. Survivor care is managed by the primary-care clinician: expert attention to the mental, physical, and sexual health of each patient will ensure the best outcomes and quality of life.

A Case of Niraparib PARP-Inhibitor Induced Sweet Syndrome in Gynecologic Cancer

Sweet Syndrome, or acute febrile neutrophilic dermatosis, is a rare inflammatory dermatologic disorder that can be spontaneous, associated with malignancy, or drug-induced. Reports of Sweet Syndrome in gynecologic oncology patients are sparse, and the majority are thought to be malignancy-associated. The case presented here represents the third case of drug-induced Sweet Syndrome in a gynecologic oncology patient. To the best of our knowledge, this is the first report of Sweet Syndrome after initiation of a poly (ADP-ribose) polymerase inhibitor (PARPi) for maintenance therapy in the treatment of high grade serous ovarian carcinoma (HGSOC). This represents one of the most severe dermatologic adverse effects of treatment with PARPi reported to date, requiring treatment discontinuation.

Does PARP Inhibition Sensitize Chondrosarcoma Cell Lines to Chemotherapy or Radiotherapy? Results From a Three-dimensional Spheroid Cell Model

BACKGROUND

Chondrosarcomas are well known for their resistance to conventional chemotherapy and radiotherapy treatment regimens, which is particularly detrimental in patients who have unresectable tumors. Recently, inhibition of poly(ADP-ribose) polymerase (PARP) by talazoparib was shown to sensitize chondrosarcoma cell lines to chemotherapy (temozolomide) or radiotherapy, irrespective of isocitrate dehydrogenase (IDH) mutation status. Because two-dimensionally grown cell lines have limitations and may not accurately represent the clinical response to drug treatment, we aimed to use a more representative three-dimensional alginate spheroid chondrosarcoma model. It is important to test therapeutic agents in vitro before testing them in animals or humans; therefore, we aimed to determine the effectiveness of a PARP inhibitor in reducing the viability of chondrosarcoma spheroids. Using a more stringent, complex in vitro model refines future therapeutic options for further investigation in animal models, increasing efficiency, reducing unnecessary animal use, and saving time and cost.

QUESTIONS/PURPOSES

(1) Does talazoparib treatment slow or inhibit the growth of chondrosarcoma spheroids, and does an increased treatment duration change the drug's effect? (2) Does talazoparib work in synergy with temozolomide treatment to reduce the viability of chondrosarcoma spheroids? (3) Does talazoparib work in synergy with radiotherapy treatment to reduce the viability of chondrosarcoma spheroids?

METHODS

Three representative conventional chondrosarcoma cell lines (CH2879 [IDH wildtype], JJ012 [IDH1 mutant], and SW1353 [IDH2 mutant]) were cultured as alginate spheroids and treated with talazoparib (0.001 to 10 µM), temozolomide (0.01 to 100 µM), or combinations of these drugs for 3, 7, and 14 days, representing different stages of spheroid growth. The cell lines were selected to represent a variety of IDH mutation statuses and were previously validated in spheroid culturing. Temozolomide was chosen because of its previous success when combined with PARP inhibitors, dissimilar to other commonly used chemotherapies. The effect on spheroid viability was assessed using three cell viability assays. Additionally, spheroid count, morphology, proliferation, and apoptosis were assessed. The effect of talazoparib (5 to 10 nM) combined with ƴ-radiation applied using a 137 C source (0 to 6 Gy) was assessed as surviving fractions by counting the number of spheroids (three). The therapeutic synergy of low-concentration talazoparib (5 to 10 nM) with temozolomide or radiotherapy was determined by calculating Excess over Bliss scores.

RESULTS

Talazoparib treatment reduced the spheroid viability of all three cell lines after 14 days (IC 50 ± SD of CH2879: 0.1 ± 0.03 µM, fold change: 220; JJ012: 12 ± 1.4 µM, fold change: 4.8; and SW1353: 1.0 ± 0.2 µM, fold change: 154), compared with 3-day treatments of mature spheroids. After 14 days of treatment, the Excess over Bliss scores for 100 µM temozolomide and talazoparib indicated synergistic efficacy (Excess over Bliss scores: CH2879 59% [lower 95% CI 52%], JJ012 18% [lower 95% CI 8%], and SW1353 55% [lower 95% CI 25%]) of this combination treatment. A stable synergistic effect of talazoparib and radiotherapy was present only in JJ012 spheroids at a 4Gƴ radiation dose (Excess over Bliss score: 22% [lower 95% CI 6%]).

CONCLUSION

In our study, long-term PARP inhibition was more effective than short-term treatment, and only one of the three chondrosarcoma spheroid lines was sensitive to combined PARP inhibition and radiotherapy. These findings suggest subsequent animal studies should focus on long-term PARP inhibition, and temozolomide combined with talazoparib has a higher chance of success than combination with radiotherapy.

CLINICAL RELEVANCE

Combination treatment of talazoparib and temozolomide was effective in reducing the viability of chondrosarcoma spheroids and spheroid growth, regardless of IDH mutation status, providing rationale to replicate this treatment combination in an animal chondrosarcoma model.

Incidence and risk of hypertension associated with PARP inhibitors in cancer patients: a systematic review and meta-analysis

OBJECTIVE

To analyze the incidence and risk of hypertension associated with poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitors in cancer patients and provide reference for clinicians.

METHODS

We used R software to conduct a meta-analysis of phase II/III randomized controlled trials (RCT) on PARP inhibitors for cancer treatment published in PubMed, Embase, Clinical Trials, Cochrane Library and Web of Science from inception to July 29th, 2022.

RESULTS

We included 32 RCTs with 10,654 participants for this meta-analysis. For total PARP inhibitors, the incidence and risk ratio of all-grade hypertension were 12% and 1.22 (95% CI: 0.91-1.65, P = 0.19, I² = 81%), and the incidence and risk ratio of grade 3-4 hypertension were 4% and 1.24 (95% CI: 0.74-2.08, P = 0.42, I² = 68%). Compared with the control group, the niraparib group, olaparib 800 mg/day group, and olaparib plus cediranib group increased the risk of any grade and grade 3-4 hypertension, while the veliparib group and rucaparib group did not increase the risk of any grade and grade 3-4 hypertension, and olaparib 200 mg-600 mg/day group (exclude olaparib plus cediranib regime) reduced the risk of any grade and grade 3-4 hypertension.

CONCLUSION

Olaparib 200-600 mg/day (excluding olaparib plus cediranib regimen) may be the most suitable PARP inhibitor for cancer patients with high risk of hypertension, followed by veliparib and rucaparib. Niraparib, olaparib 800 mg/day and olaparib combined with cediranib may increase the risk of developing hypertension in cancer patients, clinicians should strengthen the monitoring of blood pressure in cancer patients and give medication in severe cases.

Current status and future promise of next-generation poly (ADP-Ribose) polymerase 1-selective inhibitor AZD5305

The family of poly (ADP-ribose) polymerases (PARPs) consists of 17 members, which have been demonstrated as having effects on a series of cellular processes, including DNA replication and repair. PARP inhibitors (PARPi) suppress DNA repair through "PARP trapping", thus, constitute an important treatment option for cancer nowadays. In addition, PARP inhibition and homologous recombination repair (HRR) defects are synthetically lethal, giving a promising therapeutic for homologous recombination repair deficient (HRD) tumors including BRCA mutation. However, overlapping hematologic toxicity causes PARPi to fail in combination with some first-line chemotherapies. Furthermore, recent literature has demonstrated that PARP1 inhibition and PARP1-DNA trapping are key for antitumor activity in HRD cancer models. Currently approved PARPi have shown varying levels of selectivity for the entire 17-member PARP family, hence contribute to toxicity. Together, these findings above have provided the necessity and feasibility of developing next-generation PARPi with improved selectivity for PARP1, expanding significant clinical values and wide application prospects both in monotherapy and combination with other anticancer agents. In this review, we summery the latest research of current approved PARPi, discuss the current status and future promise of next-generation PARP1-selective inhibitor AZD5305, including its reported progress up to now and anticipated impact on clinical.

Targeting RNA:protein interactions with an integrative approach leads to the identification of potent YBX1 inhibitors

RNA-protein interactions (RPIs) are promising targets for developing new molecules of therapeutic interest. Nevertheless, challenges arise from the lack of methods and feedback between computational and experimental techniques during the drug discovery process. Here, we tackle these challenges by developing a drug screening approach that integrates chemical, structural and cellular data from both advanced computational techniques and a method to score RPIs in cells for the development of small RPI inhibitors; and we demonstrate its robustness by targeting Y-box binding protein 1 (YB-1), a messenger RNA-binding protein involved in cancer progression and resistance to chemotherapy. This approach led to the identification of 22 hits validated by molecular dynamics (MD) simulations and nuclear magnetic resonance (NMR) spectroscopy of which 11 were found to significantly interfere with the binding of messenger RNA (mRNA) to YB-1 in cells. One of our leads is an FDA-approved poly(ADP-ribose) polymerase 1 (PARP-1) inhibitor. This work shows the potential of our integrative approach and paves the way for the rational development of RPI inhibitors.

Bioanalytical Methods for Poly(ADP-Ribose) Polymerase Inhibitor Quantification: A Review for Therapeutic Drug Monitoring

BACKGROUND

Therapeutic drug monitoring (TDM) of poly(ADP-ribose) polymerase inhibitors (PARPis) is an exploratory practice aimed at improving the quality of treatment through personalized therapy. Currently, there are 4 European Medicines Agency-approved and US Food and Drug Administration-approved PARPis available clinically whose quantification requires validated analytical methods: olaparib, niraparib, rucaparib, and talazoparib. The purpose of this literature review was to highlight the pharmacological features of PARPis that could support their TDM practice and provide a detailed discussion of the available liquid chromatography coupled with tandem mass spectrometry methods for their quantification.

METHODS

Using several Medical Subject Heading terms, the literature was searched using several research engines, including SciFinder, Web of Science, Google Scholar, and PubMed, to find articles published before August 2022.

RESULTS

Exposure-efficacy and exposure-safety profiles, drug-drug interactions, and hepatic/renal impairment of PARPis provide the potential rationale to monitor their concentrations through TDM. Several bioanalytical methods for their quantification have been reported and compared, and a great deal of heterogeneity has been found among methods, regarding both their analytical and regulatory aspects.

CONCLUSIONS

In addition to reducing toxicity and increasing the efficacy of PARPis therapy, TDM could be beneficial to thoroughly investigate the exposure-response relationships of PARPis and to establish pharmacokinetic thresholds for clinical decisions. Based on the comparison of published bioanalytical methods, their transferability and validation both play a key role in method selection. For future use in clinical TDM, we anticipate that bioanalytical methods should address every analytical need more thoroughly and should be validated with standardized guidelines.

Clinical application of PARP inhibitors in ovarian cancer: from molecular mechanisms to the current status

As a kind of gynecological tumor, ovarian cancer is not as common as cervical cancer and breast cancer, but its malignant degree is higher. Despite the increasingly mature treatment of ovarian cancer, the five-year survival rate of patients is still less than 50%. Based on the concept of synthetic lethality, poly (ADP- ribose) polymerase (PARP) inhibitors target tumor cells with defects in homologous recombination repair(HRR), the most significant being the target gene Breast cancer susceptibility genes(BRCA). PARP inhibitors capture PARP-1 protein at the site of DNA damage to destroy the original reaction, causing the accumulation of PARP-DNA nucleoprotein complexes, resulting in DNA double-strand breaks(DSBs) and cell death. PARP inhibitors have been approved for the treatment of ovarian cancer for several years and achieved good results. However, with the widespread use of PARP inhibitors, more and more attention has been paid to drug resistance and side effects. Therefore, further research is needed to understand the mechanism of PARP inhibitors, to be familiar with the adverse reactions of the drug, to explore the markers of its efficacy and prognosis, and to deal with its drug resistance. This review elaborates the use of PARP inhibitors in ovarian cancer.

Onconephrology: Update in Anticancer Drug-Related Nephrotoxicity

The relation that connects cancer and renal damage is bidirectional and this renal damage worsens quality of life and increases morbidity in high-complexity patients such as patients with cancer and kidney injury. Strikingly, in the last decade, the treatment of advanced cancer has clearly advanced in terms of new therapeutic strategies with the ability to transform the advanced metastatic cancer in a chronic condition. In this new era of cancer therapies, cancer treatment including conventional chemotherapy, targeted cancer agents and immunotherapies among others are significantly associated with kidney injury. Renal toxicity that is currently seen in onconephrology departments is in part related to the new therapies such as immunotherapy, and to the prolonged survival achieved at the expense of increasing therapy lines, and a combination of different drugs. In this review, we will discuss in a practical way, nephrotoxicity caused by the main oncospecific treatments such as classical chemotherapy agents, targeted therapies, and immunotherapy. In addition, strategies for prevention and management recommendations in patients with malignancies and kidney disease will also be addressed.

Poly-ADP-ribose polymerase (PARP) inhibitors and ovarian function

Poly-ADP-ribose polymerase (PARP) plays an important role in DNA damage detection and repair. PARP inhibitors (PARPi) are a novel class of targeted agents used widely in the treatment of female cancer patients with BRCA mutations, including younger patients. However, the impact of PARPi on ovarian function remains a considerable problem in clinical practice. In this review article, we summarize the current understanding of PARPi's effects on the function of ovary and discuss their potential underlying mechanisms, highlighting the significance of further investigation on the criterion for ovarian failure and its preventive approaches during PARPi treatment.

Clinical Application of Poly(ADP-Ribose) Polymerase (PARP) Inhibitors in Ovarian Cancer

The treatment of ovarian cancer has remained a clinical challenge despite high rates of initial response to platinum-based chemotherapy. Patients are generally diagnosed at an advanced stage with significant disease burden, which portends to worse survival outcomes. Deficiencies in the homologous recombination (HRD) DNA damage repair (DDR) pathway and mutations in the BRCA1/2 genes have been found in ovarian carcinomas. Moreover, patients with these specific molecular aberrations have demonstrated sensitivity and thus improved response to poly(ADP-ribose) polymerase inhibitor (PARPi) treatment. The results of various clinical trials exploring the use of PARPi in different populations of ovarian cancer patients have shown impressive survival and response outcomes. With expanding indications, the use of PARPi has thus changed the landscape of ovarian cancer treatment. In this chapter, we will describe the different settings of PARPi treatment-frontline maintenance therapy, maintenance therapy for patients with recurrent platinum-sensitive disease, and treatment in the recurrent setting-and discuss treatment considerations and management of toxicities, as well as offer thoughts on future directions.

New Concepts in Cardio-Oncology

Cancer and cardiovascular disease are the two major causes of morbidity and mortality in worldwide. Discovering new therapeutic agents for the management of breast cancer (BC) has increased the numbers of cancer survivors but with the risk of cardiovascular adverse events (CV-AEs). All drugs can potentially damage the cardiovascular system, with different types of clinical manifestations from ischemic myocardial disease to vasculitis, thrombosis or pericarditis. An early detection of CV-AEs guarantees an earlier treatment, which is associated with better outcomes. Cardio-oncology field enlarged its studies to improve prevention, monitoring and treatment of all cardiotoxic manifestations related to old or modern oncological agents. A multidisciplinary approach with a close partnership between oncologists and cardiologists is essential for an optimal management and therapeutic decision-making. The aim of this chapter is to review all types of cardiotoxic manifestations related to novel and old agents approved for treatment of BC patients including chemotherapy, anti-HER2 agents, cyclin-dependent kinase 4/6 inhibitors, PolyADP-ribose polymerase (PARP) inhibitors, antiangiogenic drugs and immunotherapy. We also focused our discussion on prevention, monitoring, treatment, and management of CV-AEs.

Olaparib and advanced ovarian cancer: Summary of the past and looking into the future

Ovarian cancer (OC) is women's eighth most common cancer, bearing the highest mortality rates of all female reproductive system malignancies. Poly (ADP-ribose) polymerase inhibitors (PARPis) have reshaped the treatment scenario of metastatic OC as a maintenance post platinum-based chemotherapy. Olaparib is the first PARPi developed for this disease. Results from Study 42, Study 19, SOLO2, OPINION, SOLO1, and PAOLA-1 clinical trials, led to the FDA and EMA approval of olaparib for the maintenance treatment of women with high-grade epithelial ovarian, fallopian tube, or primary peritoneal cancer without platinum progression: in the platinum-sensitive recurrent OC; in the newly diagnosed setting in case Breast Cancer (BRCA) mutations and, in combination with bevacizumab, in case of BRCA mutation or deficiency of homologous recombination genes. In this review, we synthetized olaparib's pharmacokinetic and pharmacodynamic properties and its use in special populations. We summarized the efficacy and safety of the studies leading to the current approvals and discussed the future developments of this agent.

PARP inhibitor-related haemorrhages: What does the real-world study say?

Background

PARP inhibitors (PARPis) are novel molecular targeted therapeutics for inhibition of DNA repair in tumor cells, which are commonly used in ovarian cancer. Recent case reports have indicated that haemorrhages-related adverse events may be associated with PARPis. However, little is known about the characteristics and signal strength factors of this kind of adverse event.

Methods

A pharmacovigilance study from January 2004 to March 2022 based on the FDA adverse event reporting system (FAERS) database was conducted by adopting the proportional imbalance method based on the four algorithms, including the reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian confidence propagation neural networks (BCPNN) and multi-item gamma Poisson shrinker (MGPS).

Results

725 cases of PARPi-haemorrhages-related adverse events were identified with a fatality rate of 4.72% (30/725) and a median age of 67 years. About 88% of the adverse events occurred within 6 months, and the median duration (IQR) was 68 days. Most adverse events (n=477, 75.11%) were related to the treatment of niraparib. Importantly, niraparib exposure was associated with a significant increase in haemorrhages-related adverse events (ROR (95% CI), 1.13(1.03,1.23), PRR (χ2), 1.12(7.32), IC (IC 025), 0.17(0.15). In addition, petechiae, gingival bleeding, bloody urine, as well as rectal haemorrhage should be monitored when using niraparib.

Conclusion

Recognition and management of PARPi-haemorrhages-related adverse events is of significance to clinical practice. In this study, we provided a safety signal that haemorrhage-related adverse events should be monitored for when using niraparib. However, larger and more robust post-market safety studies are needed to improve the quality of this evidence.

Guidance on the management of adverse reactions induced by poly(ADP-ribose) polymerase inhibitors

The common adverse reactions caused by poly (ADP-ribose) polymerase (PARP) inhibitors include hematological toxicity, gastrointestinal toxicity and fatigue. The main prevention and treatment of hematological toxicity include: regular blood tests, referral to hematology department when routine treatment is ineffective, and being alert of myelodysplastic syndrome/acute myeloid leukemia. The key points to deal with gastrointestinal toxicity include: taking medicine at the right time, light diet, appropriate amount of drinking water, timely symptomatic treatment, prevention of expected nausea and vomiting, and so on. For fatigue, full assessment should be completed before treatment because the causes of fatigue are various; the management includes massage therapy, psychosocial interventions and drugs such as methylphenidate and Panax quinquefolius according to the severity. In addition, niraparib and fluzoparib can cause hypertension, hypertensive crisis and palpitation. Blood pressure and heart rate monitoring, timely symptomatic treatment, and multidisciplinary consultation should be taken if necessary. When cough and dyspnea occur, high resolution CT and bronchoscopy should be performed to exclude pneumonia. If necessary, PARP inhibitors should be stopped, and glucocorticoid and antimicrobial therapy should be given. Finally, more attention should be paid to drug interaction management, patient self-management and regular monitoring to minimize the risk and harm of adverse reactions of PARP inhibitors.

Cost-effectiveness of PARP inhibitors in malignancies: A systematic review

OBJECTIVES

Poly (ADP-ribose) polymerase inhibitor (PARPi) have become a mainstay for the treatment of BRCA-mutant malignancies. PARPis are likely to be more effective but also bring an increase in costs. Thus, we aimed at evaluating the cost effectiveness of PARPis in the treatment of malignancies.

METHODS

Studies of cost effectiveness of PARPis were searched from PubMed, Web of Science, and Cochrane Library. Key information was extracted from the identified studies and reviewed. Quality of the included studies was evaluated using Quality of Health Economic Studies (QHES) instrument. Modeling techniques, measurement of parameters and uncertainty analysis were analyzed across studies. Interventions and cost-effectiveness results were reported stratified by patient population.

RESULTS

Among the 25 studies identified, we included 17 on ovarian cancer, 2 on breast cancer, 3 on pancreatic cancer, and 3 on prostate cancer that involved olaparib, niraparib, rucaparib, and talazoparib. All studies had a QHES score of above 75. In the maintenance therapy of ovarian cancer, additional administration of olaparib was cost-effective for newly diagnosed patients after first-line platinum-based chemotherapy but was not cost-effective for platinum-sensitive recurrent patients in majority studies. However, the economic value of other PARPis in ovarian cancer as well as all PARPis in other tumors remained controversial. Cost-effectiveness of PARPi was primarily impacted by the costs of PARPi, survival time, health utility and discount rate. Moreover, genetic testing improved the cost-effectiveness of PARPi treatment.

CONCLUSIONS

PARPi is potentially cost-effective for patients with ovarian, pancreatic, or prostate cancer. Genetic testing can improve the cost-effectiveness of PARPi.

Dynamics of endogenous PARP1 and PARP2 during DNA damage revealed by live-cell single-molecule imaging

PARP1 contributes to genome architecture and DNA damage repair through its dynamic association with chromatin. PARP1 and PARP2 (PARP1/2) recognize damaged DNA and recruit the DNA repair machinery. Using single-molecule microscopy in live cells, we monitored the movement of PARP1/2 on undamaged and damaged chromatin. We identify two classes of freely diffusing PARP1/2 and two classes of bound PARP1/2. The majority (>60%) of PARP1/2 diffuse freely in both undamaged and damaged nuclei and in the presence of inhibitors of PARP1/2 used for cancer therapy (PARPi). Laser-induced DNA damage results in a small fraction of slowly diffusing PARP1 and PARP2 to become transiently bound. Treatment of cells with PARPi in the presence of DNA damage causes subtle changes in the dynamics of bound PARP1/2, but not the high levels of PARP1/2 trapping seen previously. Our results imply that next-generation PARPi could specifically target the small fraction of DNA-bound PARP1/2.

Natural phytochemicals prevent side effects in BRCA-mutated ovarian cancer and PARP inhibitor treatment

Ovarian cancer is among the most common malignant tumors in gynecology and is characterized by insidious onset, poor differentiation, high malignancy, and a high recurrence rate. Numerous studies have shown that poly ADP-ribose polymerase (PARP) inhibitors can improve progression-free survival (PFS) in patients with BRCA-mutated ovarian cancer. With the widespread use of BRCA mutation and PARP inhibitor (PARPi) combination therapy, the side effects associated with BRCA mutation and PARPi have garnered attention worldwide. Mutations in the BRCA gene increase KEAP1-NRF2 ubiquitination and reduce Nrf2 content and cellular antioxidant capacity, which subsequently produces side effects such as cardiovascular endothelial damage and atherosclerosis. PARPi has hematologic toxicity, producing thrombocytopenia, fatigue, nausea, and vomiting. These side effects not only reduce patients' quality of life, but also affect their survival. Studies have shown that natural phytochemicals, a class of compounds with antitumor potential, can effectively prevent and treat the side effects of chemotherapy. Herein, we reviewed the role of natural phytochemicals in disease prevention and treatment in recent years, including sulforaphane, lycopene, catechin, and curcumin, and found that these phytochemicals have significant alleviating effects on atherosclerosis, nausea, and vomiting. Moreover, these mechanisms of action significantly correlated with the side-effect-producing mechanisms of BRCA mutations and PARPi. In conclusion, natural phytochemicals may be effective in alleviating the side effects of BRCA mutant ovarian cancer cells and PARP inhibitors.

The potential of PARP inhibitors in targeted cancer therapy and immunotherapy

DNA damage response (DDR) deficiencies result in genome instability, which is one of the hallmarks of cancer. Poly (ADP-ribose) polymerase (PARP) enzymes take part in various DDR pathways, determining cell fate in the wake of DNA damage. PARPs are readily druggable and PARP inhibitors (PARPi) against the main DDR-associated PARPs, PARP1 and PARP2, are currently approved for the treatment of a range of tumor types. Inhibition of efficient PARP1/2-dependent DDR is fatal for tumor cells with homologous recombination deficiencies (HRD), especially defects in breast cancer type 1 susceptibility protein 1 or 2 (BRCA1/2)-dependent pathway, while allowing healthy cells to survive. Moreover, PARPi indirectly influence the tumor microenvironment by increasing genomic instability, immune pathway activation and PD-L1 expression on cancer cells. For this reason, PARPi might enhance sensitivity to immune checkpoint inhibitors (ICIs), such as anti-PD-(L)1 or anti-CTLA4, providing a rationale for PARPi-ICI combination therapies. In this review, we discuss the complex background of the different roles of PARP1/2 in the cell and summarize the basics of how PARPi work from bench to bedside. Furthermore, we detail the early data of ongoing clinical trials indicating the synergistic effect of PARPi and ICIs. We also introduce the diagnostic tools for therapy development and discuss the future perspectives and limitations of this approach.

A moving target for drug discovery: Structure activity relationship and many genome (de)stabilizing functions of the RAD52 protein

BRCA-ness phenotype, a signature of many breast and ovarian cancers, manifests as deficiency in homologous recombination, and as defects in protection and repair of damaged DNA replication forks. A dependence of such cancers on DNA repair factors less important for survival of BRCA-proficient cells, offers opportunities for development of novel chemotherapeutic interventions. The first drugs targeting BRCA-deficient cancers, poly-ADP-ribose polymerase (PARP) inhibitors have been approved for the treatment of advanced, chemotherapy resistant cancers in patients with BRCA1/2 germline mutations. Nine additional proteins that can be targeted to selectively kill BRCA-deficient cancer cells have been identified. Among them, a DNA repair protein RAD52 is an especially attractive target due to general tolerance of the RAD52 loss of function, and protective role of an inactivating mutation. Yet, the effective pharmacological inhibitors of RAD52 have not been forthcoming. In this review, we discuss advances in the state of our knowledge of the RAD52 structure, activities and cellular functions, with a specific focus on the features that make RAD52 an attractive, but difficult drug target.

Pharmacokinetics and Pharmacodynamics of PARP Inhibitors in Oncology

Olaparib, niraparib, rucaparib, and talazoparib are poly (ADP-ribose) polymerase (PARP) inhibitors approved for the treatment of ovarian, breast, pancreatic, and/or prostate cancer. Poly (ADP-ribose) polymerase inhibitors are potent inhibitors of the PARP enzymes with comparable half-maximal inhibitory concentrations in the nanomolar range. Olaparib and rucaparib are orally dosed twice a day, extensively metabolized by cytochrome P450 enzymes, and inhibitors of several enzymes and drug transporters with a high risk for drug-drug interactions. Niraparib and talazoparib are orally dosed once a day with a lower risk for niraparib and a minimal risk for talazoparib to cause drug-drug interactions. All four PARP inhibitors show moderate-to-high interindividual variability in plasma exposure. Higher exposure is associated with an increase in toxicity, mostly hematological toxicity. For talazoparib, exposure-efficacy relationships have been described, but for olaparib, niraparib, and rucaparib this relationship remains inconclusive. Further studies are required to investigate exposure-response relationships to improve dosing of PARP inhibitors, in which therapeutic drug monitoring could play an important role. In this review, we give an overview of the pharmacokinetic properties of the four PARP inhibitors, including considerations for patients with renal dysfunction or hepatic impairment, the effect of food, and drug-drug interactions. Furthermore, we focus on the pharmacodynamics and summarize the available exposure-efficacy and exposure-toxicity relationships.

Therapy-related Myeloid Neoplasms Following PARP Inhibitors: Real-life Experience

PURPOSE

To provide insights into the diagnosis and management of therapy-related myeloid neoplasms (t-MN) following PARP inhibitors (PARPi).

EXPERIMENTAL DESIGN

In a French cancer center, we identified and described the profiles of 13 t-MN diagnosed among 37 patients with ovarian cancer referred to hematology consultation for cytopenia under PARPi. Next, we described these 13 t-MN post-PARPi among 37 t-MN post ovarian cancer according to PARPi exposure. Finally, we described 69 t-MN post-PARPi in a national cohort.

RESULTS

From 2016 to 2021, cumulative incidence of t-MN was 3.5% (13/373) among patients with ovarian cancer treated with PARPi. At time of hematologic consultation, patients with t-MN had a longer PARPi exposure (9 vs. 3 months, P = 0.01), lower platelet count (74 vs. 173 G/L, P = 0.0005), and more cytopenias (2 vs. 1, P = 0.0005). Compared with t-MN not exposed to PARPi, patients with t-MN-PARPi had more BRCA1/2 germline mutation (61.5% vs. 0%, P = 0.03) but similar overall survival (OS). In the national cohort, most t-MN post-PARPi had a complex karyotype (61%) associated with a high rate of TP53 mutation (71%). Median OS was 9.6 months (interquartile range, 4-14.6). In multivariate analysis, a longer time between end of PARPi and t-MN (HR, 1.046; P = 0.02), olaparib compared with other PARPi (HR, 5.82; P = 0.003) and acute myeloid leukemia (HR, 2.485; P = 0.01) were associated with shorter OS.

CONCLUSIONS

In a large series, we described a high incidence of t-MN post-PARPi associated with unfavorable cytogenetic and molecular abnormalities leading to poor OS. Early detection is crucial, particularly in cases of delayed cytopenia.

DNA Damage Response in Cancer Therapy and Resistance: Challenges and Opportunities

Resistance to chemo- and radiotherapy is a common event among cancer patients and a reason why new cancer therapies and therapeutic strategies need to be in continuous investigation and development. DNA damage response (DDR) comprises several pathways that eliminate DNA damage to maintain genomic stability and integrity, but different types of cancers are associated with DDR machinery defects. Many improvements have been made in recent years, providing several drugs and therapeutic strategies for cancer patients, including those targeting the DDR pathways. Currently, poly (ADP-ribose) polymerase inhibitors (PARP inhibitors) are the DDR inhibitors (DDRi) approved for several cancers, including breast, ovarian, pancreatic, and prostate cancer. However, PARPi resistance is a growing issue in clinical settings that increases disease relapse and aggravate patients' prognosis. Additionally, resistance to other DDRi is also being found and investigated. The resistance mechanisms to DDRi include reversion mutations, epigenetic modification, stabilization of the replication fork, and increased drug efflux. This review highlights the DDR pathways in cancer therapy, its role in the resistance to conventional treatments, and its exploitation for anticancer treatment. Biomarkers of treatment response, combination strategies with other anticancer agents, resistance mechanisms, and liabilities of treatment with DDR inhibitors are also discussed.

Dose Adjustment of Poly (ADP‑Ribose) Polymerase Inhibitors in Patients with Hepatic or Renal Impairment

Poly (ADP-ribose) polymerase (PARP) inhibitors are small-molecule inhibitors of PARP enzymes (including PARP1, PARP2, and PARP3) that exhibit activity against tumor cells with defects in DNA repair. In recent years, five PARP inhibitors, olaparib, niraparib, rucaparib, talazoparib and veliparib, have been developed for the treatment of solid tumors, particularly in patients with breast-related cancer antigen (BRCA) 1/2 mutations, or those without a functional homologous recombination repair pathway. These novel treatments exhibit improved efficacy and toxicity when compared to conventional chemotherapy agents. The five PARP inhibitors are eliminated primarily via the liver and kidneys, hepatic or renal impairment may significantly affect their pharmacokinetics (PK). Therefore, it is important to know the effects of hepatic or renal impairment on the PK and safety of PARP inhibitors. In this review, we characterize and summarize the effects of hepatic and renal function on the PK of PARP inhibitors and provide specific recommendations for clinicians when prescribing PARP inhibitors in patients with hepatic or renal impairment.

Poly (ADP-ribose) polymerases as PET imaging targets for central nervous system diseases

Poly (ADP-ribose) polymerases (PARPs) constitute of 17 members that are associated with divergent cellular processes and play a crucial role in DNA repair, chromatin organization, genome integrity, apoptosis, and inflammation. Multiple lines of evidence have shown that activated PARP1 is associated with intense DNA damage and irritating inflammatory responses, which are in turn related to etiologies of various neurological disorders. PARP1/2 as plausible therapeutic targets have attracted considerable interests, and multitudes of PARP1/2 inhibitors have emerged for treating cancer, metabolic, inflammatory, and neurological disorders. Furthermore, PARP1/2 as imaging targets have been shown to detect, delineate, and predict therapeutic responses in many diseases by locating and quantifying the expression levels of PARP1/2. PARP1/2-directed noninvasive positron emission tomography (PET) has potential in diagnosing and prognosing neurological diseases. However, quantitative PARP PET imaging in the central nervous system (CNS) has evaded us due to the challenges of developing blood-brain barrier (BBB) penetrable PARP radioligands. Here, we review PARP1/2's relevance in CNS diseases, summarize the recent progress on PARP PET and discuss the possibilities of developing novel PARP radiotracers for CNS diseases.

Clinical Pharmacokinetics and Pharmacodynamics of Rucaparib

Rucaparib is an oral small-molecule poly(ADP-ribose) polymerase inhibitor indicated for patients with recurrent ovarian cancer in the maintenance and treatment settings and for patients with metastatic castration-resistant prostate cancer associated with a deleterious BRCA1 or BRCA2 mutation. Rucaparib has a manageable safety profile; the most common adverse events reported were fatigue and nausea in both indications. Accumulation in plasma exposure occurred after repeated administration of the approved 600-mg twice-daily dosage. Steady state was achieved after continuous twice-daily dosing for a week. Rucaparib has moderate oral bioavailability and can be dosed with or without food. Although a high-fat meal weakly increased maximum concentration and area under the curve, the effect was not clinically significant. A mass balance analysis indicated almost a complete dose recovery of rucaparib over 12 days, with metabolism, renal, and hepatic excretion as the elimination routes. A population pharmacokinetic analysis of rucaparib revealed no effect of age, sex, race, or body weight. No starting dose adjustments were necessary for patients with mild-to-moderate hepatic or renal impairment; the effect of severe organ impairment on rucaparib exposure has not been evaluated. In patients, rucaparib moderately inhibited cytochrome P450 (CYP) 1A2 and weakly inhibited CYP3As, CYP2C9, and CYP2C19. Rucaparib weakly increased systemic exposures of oral contraceptives and oral rosuvastatin and marginally increased the exposure of oral digoxin (a P-glycoprotein substrate). In vitro studies suggested that rucaparib inhibits transporters MATE1, MATE2-K, OCT1, and OCT2. No clinically meaningful drug interactions with rucaparib as a perpetrator were observed. An exposure-response analysis revealed dose-dependent changes in selected clinical efficacy and safety endpoints. Overall, this article provides a comprehensive review of the clinical pharmacokinetics, pharmacodynamics, drug-drug interactions, effects of intrinsic and extrinsic factors, and exposure-response relationships of rucaparib.

Preclinical Characterization of AZD5305, A Next-Generation, Highly Selective PARP1 Inhibitor and Trapper

PURPOSE

We hypothesized that inhibition and trapping of PARP1 alone would be sufficient to achieve antitumor activity. In particular, we aimed to achieve selectivity over PARP2, which has been shown to play a role in the survival of hematopoietic/stem progenitor cells in animal models. We developed AZD5305 with the aim of achieving improved clinical efficacy and wider therapeutic window. This next-generation PARP inhibitor (PARPi) could provide a paradigm shift in clinical outcomes achieved by first-generation PARPi, particularly in combination.

EXPERIMENTAL DESIGN

AZD5305 was tested in vitro for PARylation inhibition, PARP-DNA trapping, and antiproliferative abilities. In vivo efficacy was determined in mouse xenograft and PDX models. The potential for hematologic toxicity was evaluated in rat models, as monotherapy and combination.

RESULTS

AZD5305 is a highly potent and selective inhibitor of PARP1 with 500-fold selectivity for PARP1 over PARP2. AZD5305 inhibits growth in cells with deficiencies in DNA repair, with minimal/no effects in other cells. Unlike first-generation PARPi, AZD5305 has minimal effects on hematologic parameters in a rat pre-clinical model at predicted clinically efficacious exposures. Animal models treated with AZD5305 at doses ≥0.1 mg/kg once daily achieved greater depth of tumor regression compared to olaparib 100 mg/kg once daily, and longer duration of response.

CONCLUSIONS

AZD5305 potently and selectively inhibits PARP1 resulting in excellent antiproliferative activity and unprecedented selectivity for DNA repair deficient versus proficient cells. These data confirm the hypothesis that targeting only PARP1 can retain the therapeutic benefit of nonselective PARPi, while reducing potential for hematotoxicity. AZD5305 is currently in phase I trials (NCT04644068).

Exploiting DNA Ligase III addiction of multiple myeloma by flavonoid Rhamnetin

Background

DNA ligases are crucial for DNA repair and cell replication since they catalyze the final steps in which DNA breaks are joined. DNA Ligase III (LIG3) exerts a pivotal role in Alternative-Non-Homologous End Joining Repair (Alt-NHEJ), an error-prone DNA repair pathway often up-regulated in genomically unstable cancer, such as Multiple Myeloma (MM). Based on the three-dimensional (3D) LIG3 structure, we performed a computational screening to identify LIG3-targeting natural compounds as potential candidates to counteract Alt-NHEJ activity in MM.

Methods

Virtual screening was conducted by interrogating the Phenol Explorer database. Validation of binding to LIG3 recombinant protein was performed by Saturation Transfer Difference (STD)—nuclear magnetic resonance (NMR) experiments. Cell viability was analyzed by Cell Titer-Glo assay; apoptosis was evaluated by flow cytometric analysis following Annexin V-7AAD staining. Alt-NHEJ repair modulation was evaluated using plasmid re-joining assay and Cytoscan HD. DNA Damage Response protein levels were analyzed by Western blot of whole and fractionated protein extracts and immunofluorescence analysis. The mitochondrial DNA (mtDNA) copy number was determined by qPCR. In vivo activity was evaluated in NOD-SCID mice subcutaneously engrafted with MM cells.

Results

Here, we provide evidence that a natural flavonoid Rhamnetin (RHM), selected by a computational approach, counteracts LIG3 activity and killed Alt-NHEJ-dependent MM cells. Indeed, Nuclear Magnetic Resonance (NMR) showed binding of RHM to LIG3 protein and functional experiments revealed that RHM interferes with LIG3-driven nuclear and mitochondrial DNA repair, leading to significant anti-MM activity in vitro and in vivo.

Conclusion

Taken together, our findings provide proof of concept that RHM targets LIG3 addiction in MM and may represent therefore a novel promising anti-tumor natural agent to be investigated in an early clinical setting.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03705-z.

Efficacy and safety of Gemogenovatucel-T (Vigil) immunotherapy for advanced ovarian carcinoma: A systematic review and meta-analysis of randomized controlled trials

In recent years, many clinical trials have shown the safety and efficacy of Gemogenovatucel-T (Vigil) in the treatment of advanced OC patients. The purpose of this study was to explore the safety and efficacy of Gemogenovatucel-T (Vigil) in the first-line maintenance of advanced ovarian carcinoma based on the randomized controlled trials (RCTs). Randomized controlled trials (RCTs) on Gemogenovatucel-T (Vigil) immunotherapy for advanced ovarian carcinoma were searched in PubMed, Embase, Cochrane Library and Web of Science up to December 31, 2021. The following study characteristics were investigated: baseline study characteristics, overall survival, recurrence free survival, recurrence free survival median time, and complication. A total of 36 articles were obtained, and seven suitable RCTs with a total sample size of 322 patients were eventually included in this meta-analysis. Overall survival (OS): from time of randomization: HR=0.48 (95% CI: 0.32 to 0.72), Z=3.55, P<0.001; from time of tissue procurement: HR=0.51 (95% CI: 0.33 to 0.78), Z=3.07, P=0.002. Recurrence free survival (RFS): from time of randomization: HR=0.43 (95% CI: 0.30 to 0.62), Z=4.61, P<0.001; from time of tissue procurement: HR=0.45 (95% CI: 0.31 to 0.65), Z=4.26, P<0.001. RFS median time: from time of randomization: HR=1.57 (95% CI: 1.16 to 2.11), Z=2.95, P=0.003; from time of tissue procurement: HR=2.16 (95% CI: 1.12 to 4.17), Z=2.29, P=0.022. This study found that Gemogenovatucel-T (Vigil) immunotherapy provided significant OS and RFS benefits, particularly in advanced OC patients with BRCA wild type. At the same time, treatment with the Gemogenovatucel-T (Vigil) is safer than other treatment modalities and does not have any toxic effects.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier (CRD42022300367).

A multi-task FP-GNN framework enables accurate prediction of selective PARP inhibitors

PARP (poly ADP-ribose polymerase) family is a crucial DNA repair enzyme that responds to DNA damage, regulates apoptosis, and maintains genome stability; therefore, PARP inhibitors represent a promising therapeutic strategy for the treatment of various human diseases including COVID-19. In this study, a multi-task FP-GNN (Fingerprint and Graph Neural Networks) deep learning framework was proposed to predict the inhibitory activity of molecules against four PARP isoforms (PARP-1, PARP-2, PARP-5A, and PARP-5B). Compared with baseline predictive models based on four conventional machine learning methods such as RF, SVM, XGBoost, and LR as well as six deep learning algorithms such as DNN, Attentive FP, MPNN, GAT, GCN, and D-MPNN, the evaluation results indicate that the multi-task FP-GNN method achieves the best performance with the highest average BA, F1, and AUC values of 0.753 ± 0.033, 0.910 ± 0.045, and 0.888 ± 0.016 for the test set. In addition, Y-scrambling testing successfully verified that the model was not results of chance correlation. More importantly, the interpretability of the multi-task FP-GNN model enabled the identification of key structural fragments associated with the inhibition of each PARP isoform. To facilitate the use of the multi-task FP-GNN model in the field, an online webserver called PARPi-Predict and its local version software were created to predict whether compounds bear potential inhibitory activity against PARPs, thereby contributing to design and discover better selective PARP inhibitors.

Efficacy evaluation of multi-immunotherapy in ovarian cancer: From bench to bed

Ovarian cancer, one of the most common gynecological malignancies, is characterized by high mortality and poor prognosis. Cytoreductive surgery and chemotherapy remain the mainstay of ovarian cancer treatment, and most women experience recurrence after standard care therapies. There is compelling evidence that ovarian cancer is an immunogenic tumor. For example, the accumulation of tumor-infiltrating lymphocytes is associated with increased survival, while increases in immunosuppressive regulatory T cells are correlated with poor clinical outcomes. Therefore, immunotherapies targeting components of the tumor microenvironment have been gradually integrated into the existing treatment options, including immune checkpoint blockade, adoptive cell therapy, and cancer vaccines. Immunotherapies have changed guidelines for maintenance treatment and established a new paradigm in ovarian cancer treatment. Despite single immunotherapies targeting DNA repair mechanisms, immune checkpoints, and angiogenesis bringing inspiring efficacy, only a subset of patients can benefit much from it. Thus, the multi-immunotherapy investigation remains an active area for ovarian cancer treatment. The current review provides an overview of various clinically oriented forms of multi-immunotherapy and explores potentially effective combinational therapies for ovarian cancer.

Understanding the needs and perspectives of ovarian cancer patients when considering PARP inhibitor maintenance therapy: Findings from two online community events

•

Patients engaged in online patient communities have numerous educational needs regarding PARP inhibitors.

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2 online events were held to sample ovarian cancer patient perceptions of, and information seeking about PARP inhibitors.

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Major themes included side effects, benefits, clinical trial results, genetic mutations, and cost.

•

Patients would likely benefit from patient-centered educational tools regarding PARP inhibitors.

Objective

The online environment is an ideal setting to understand how many women seek, receive, and understand information about cancer treatment. The purpose of this study was to understand women’s needs and information-seeking around Poly ADP ribose polymerase (PARP) inhibitors, an oral medication commonly prescribed as maintenance therapy at the conclusion of primary chemotherapy for ovarian cancer.

Methods

We held online discussion events with two social media communities, #gyncsm social media on Twitter and the Smart Patients ovarian cancer community, in November 2020, to sample ovarian cancer patient perceptions of, and information seeking about PARP inhibitors. Focused questions were presented to both communities, with participants able to answer and elaborate upon these questions, as well as to add their own comments or topics. Qualitative content analysis was performed on the transcripts from the two online events.

Results

A total of 254 unique tweets and 71 messages were generated from the Twitter and Smart Patients conversations, respectively. The majority of the content from these two events could be categorized into five major themes: (1) concerns about side effects, (2) expectations of benefit, (3) desire for more information regarding clinical trials, ) (4) desire to better understand the relationship between mutation status and PARP inhibitor effectiveness, and (5) financial toxicity. Misinformation was rarely identified.

Conclusions

Women with ovarian cancer who are engaged in online patient communities have numerous educational needs regarding PARP inhibitors. Given the complexity of clinical research on PARP inhibitors, patients would likely benefit from patient-centered educational tools.

Novel approach of desensitization in allergic reaction to Olaparib

INTRODUCTION

PARP (Poly ADP Ribose Polymerase) inhibitors are an effective maintenance therapy for various entities, such as BRCA (breast cancer gene) mutated or HRD (homologous recombination deficiency) positive primary platin-sensitive advanced ovarian cancer after platin induction therapy and in relapse after responding to carboplatin reinduction. Other entities are metastatic BRCA mutated pancreas, prostate and Her2-negative breast cancer. Therefore, patients with allergic reactions to PARP inhibitors should undergo a desensitization procedure to be able to receive this efficient therapy.

CASE REPORT

We conducted a two-day desensitization on a 45-year-s old patient with advanced ovarian cancer who displayed symptoms of an allergic reaction to Olaparib.

MANAGEMENT AND OUTCOME

Using an Olaparib tablet suspension, we orally administered increasing Olaparib doses, starting with 12.5 mg and reaching a cumulative dose of 387.5 mg on the first day and starting with 100 mg and reaching a cumulative dose of 600 mg on the second day, without concomitant antiallergic medication.Except for mild erythema on day one receding within the hour, no further allergic reactions appeared during desensitization. The patient has since received 300 mg of Olaparib twice a day without further complications or interruptions.

CONCLUSION

Desensitization in a two-day suspension protocol is a safe method that ensures effective maintenance therapy for patients with allergic reactions to PARP inhibitors.

The role of Platinum(IV)-based antitumor drugs and the anticancer immune response in medicinal inorganic chemistry. A systematic review from 2017 to 2022

Platinum-based antitumor drugs have been used in many types of tumors due to its broad antitumor spectrum in clinic. Encouraged by the cisplatin's (CDDP) worldwide success in cancer chemotherapy, the research in platinum-based antitumor drugs has evolved from traditional platinum drug to multi-ligand and multifunctional platinum prodrugs over half a century. With the rapid development of metal drugs and the anticancer immune response, challenges and opportunities in platinum drug research have been shifted from traditional platinum-based drugs to platinum-based hybrids and the direction of development is tending toward photodynamic therapy, nano-delivery therapy, drug combination, targeted therapy, diagnostic therapy, immune-combination therapy and tumor stem cell therapy. In this review, we first exhaustively overviewed the role of platinum-based antitumor prodrugs and the anticancer immune response in medicinal inorganic chemistry based on the special nanomaterials, the modification of specific ligands, and the multiple functions obtained that are beneficial for tumor therapy in the last five years. We also categorized them according to drug potency and function. There hasn't been a comprehensive evaluation of precursor platinum drugs in prior articles. And a multifarious approach to distinguish and detail the variety of alterations of platinum-based precursors in various valence states also hasn't been summarized. In addition, this review points out the main problems at the interface of chemistry, biology, and medicine from their action mechanisms for current platinum drug development, and provides up-to-date potential strategies from drug design perspectives to circumvent those drawbacks. And a promising idea is also enlightened for researchers in the development and discovery of platinum prodrugs.

Corrected Allele Frequency of BRCA1/2 Mutations Is an Independent Prognostic Factor for Treatment Response to PARP-Inhibitors in Ovarian Cancer Patients

PARP inhibitors (PARPi) have increased treatment options in ovarian cancer, particularly in patients with BRCA1/2 mutations, although there are still marked differences in the duration of patients’ response to this targeted therapy. BRCA testing is routinely performed in tumor tissue of ovarian cancer patients. The resulting molecular pathological findings include the genetic nomenclature of the mutation, the frequency of the mutated allele (variant allele frequency, VAF), and the tumor cell content. VAF measures the percentage of mutated alleles from the total alleles in the cells of the examined tissue. The aim of this study was to investigate the significance of VAF on the therapeutic response to PARPis in ovarian cancer patients. Epithelial ovarian cancer patients harboring BRCA1/2 tumor mutations, who underwent germline testing and received PARPi therapy at the Medical University of Vienna (n = 41) were included in the study. Corrected VAF (cVAF) was calculated based on VAF, tumor cell content, and germline mutation. Patients were divided into two groups based on their cVAF. Median PFS under PARPi in patients with low cVAF was 13.0 months (IQR [10.3-not reached]) and was not reached in the high cVAF group. High cVAF was significantly associated with longer PFS in the multivariate analysis (HR = 0.07; 95% CI [0.01–0.63]; p = 0.017). In conclusion, high cVAF was associated with a significantly better response to PARPi in this study population.

PARP Inhibitors for Breast Cancer: Germline BRCA1/2 and Beyond

Simple Summary

Poly-adenosine diphosphate ribose polymerase (PARP) inhibitors (PARPi) are effective against tumors with mutations in DNA repair genes, most commonly in the BRCA1 and BRCA2 genes. Because these tumors are unable to repair their DNA, PARPi have been used to target DNA repair pathways and are useful in the treatment of breast cancers with some of these alterations. There are two FDA-approved PARPi for patients with breast cancer—olaparib and talazoparib. The data on olaparib and talazoparib in the treatment of breast cancer are summarized in this review, and we also explore potential future applications of PARPi beyond inherited BRCA mutations.

Abstract

Poly-adenosine diphosphate ribose polymerase (PARP) inhibitors (PARPi) are approved for BRCA1/2 carriers with HER2-negative breast cancer in the adjuvant setting with a high risk of recurrence as well as the metastatic setting. However, the indications for PARPi are broader for patients with other cancer types (e.g., prostate and ovarian cancer), involving additional biomarkers (e.g., ATM, PALB2, and CHEK) and genomic instability scores. Herein, we summarize the data on PARPi and breast cancer and discuss their use beyond BRCA carriers.

Unboxing the molecular modalities of mutagens in cancer

The etiology of the majority of human cancers is associated with a myriad of environmental causes, including physical, chemical, and biological factors. DNA damage induced by such mutagens is the initial step in the process of carcinogenesis resulting in the accumulation of mutations. Mutational events are considered the major triggers for introducing genetic and epigenetic insults such as DNA crosslinks, single- and double-strand DNA breaks, formation of DNA adducts, mismatched bases, modification in histones, DNA methylation, and microRNA alterations. However, DNA repair mechanisms are devoted to protect the DNA to ensure genetic stability, any aberrations in these calibrated mechanisms provoke cancer occurrence. Comprehensive knowledge of the type of mutagens and carcinogens and the influence of these agents in DNA damage and cancer induction is crucial to develop rational anticancer strategies. This review delineated the molecular mechanism of DNA damage and the repair pathways to provide a deep understanding of the molecular basis of mutagenicity and carcinogenicity. A relationship between DNA adduct formation and cancer incidence has also been summarized. The mechanistic basis of inflammatory response and oxidative damage triggered by mutagens in tumorigenesis has also been highlighted. We elucidated the interesting interplay between DNA damage response and immune system mechanisms. We addressed the current understanding of DNA repair targeted therapies and DNA damaging chemotherapeutic agents for cancer treatment and discussed how antiviral agents, anti-inflammatory drugs, and immunotherapeutic agents combined with traditional approaches lay the foundations for future cancer therapies.

Comprehensive Analysis of Adverse Events Induced by PARP Inhibitors Using JADER and Time to Onset

Poly (ADP-ribose) polymerase (PARP) inhibitors are effective against breast cancer susceptibility gene (BRCA) mutations. Clinical trials have reported hematologic toxicity and gastrointestinal symptoms as class effects of PARP inhibitors. However, information on adverse events (AEs) in a Japanese clinical cohort is currently lacking. In this study, we conducted a comprehensive survey of the AEs of two PARP inhibitors, olaparib and niraparib, using the Japanese Adverse Reaction Reporting (JADER) database provided by the Pharmaceuticals and Medical Devices Agency (PMDA). Moreover, we also analyzed the course and time to the onset of AEs. Signals were detected for 15 and 11 AEs for olaparib and niraparib, respectively. Most occurred within the first month of treatment with either agent. These results may indicate the importance of early response and monitoring after beginning PARP inhibitor therapy. The results of this study may be useful for managing side effects and suggesting supportive care for patients using PARP inhibitors in the future.

PARP1: Liaison of Chromatin Remodeling and Transcription

Poly(ADP-ribosyl)ation (PARylation) is a covalent post-translational modification and plays a key role in the immediate response of cells to stress signals. Poly(ADP-ribose) polymerase 1 (PARP1), the founding member of the PARP superfamily, synthesizes long and branched polymers of ADP-ribose (PAR) onto acceptor proteins, thereby modulating their function and their local surrounding. PARP1 is the most prominent of the PARPs and is responsible for the production of about 90% of PAR in the cell. Therefore, PARP1 and PARylation play a pleotropic role in a wide range of cellular processes, such as DNA repair and genomic stability, cell death, chromatin remodeling, inflammatory response and gene transcription. PARP1 has DNA-binding and catalytic activities that are important for DNA repair, yet also modulate chromatin conformation and gene transcription, which can be independent of DNA damage response. PARP1 and PARylation homeostasis have also been implicated in multiple diseases, including inflammation, stroke, diabetes and cancer. Studies of the molecular action and biological function of PARP1 and PARylation provide a basis for the development of pharmaceutic strategies for clinical applications. This review focuses primarily on the role of PARP1 in the regulation of chromatin remodeling and transcriptional activation.

Comparative Analyses of Poly(ADP-Ribose) Polymerase Inhibitors

Poly(ADP-ribose) polymerase inhibitors (PARPi) are approved as monotherapies in BRCA1/2-mutated (m BRCA1/2) metastatic breast and ovarian cancers, and in advanced pancreatic and metastatic castration-resistant prostate cancers. Differential safety profiles across PARPi necessitate improved mechanistic understanding of inhibitor differences, especially with expansion of PARPi indications and drug combinations. Here, we report in vitro evaluations of PARPi (–/+ PARP trapper temozolomide, TMZ) with reference to total clinical mean concentration average or maximum (tCavg, tCmax), to elucidate contributions of primary pharmacology and structural differences to clinical efficacy and safety. In biochemical assays, rucaparib and niraparib demonstrated off-target secondary pharmacology activities, and in selectivity assays, talazoparib, olaparib, and rucaparib inhibited a broader panel of PARP enzymes. In donor-derived human bone marrow mononuclear cells, only olaparib both increased early apoptosis and decreased the cell viability half inhibitory concentration (IC50) at ≤ tCavg, whereas other PARPi only did so in the presence of TMZ. In cancer cell lines with DNA damage repair mutations, all PARPi decreased cell viability in H1048 but not TK6 cells, and only talazoparib decreased cell growth in DU145 cells at ≤ tCavg concentrations. When combined with low dose TMZ, only talazoparib left-shifted the functional consequences of PARP trapping (S-phase arrest, apoptosis, S-phase double-stranded breaks) and reduced cell viability/growth in TK6 and DU145 cell lines at ≤ tCavg, whereas the other inhibitors required high-dose TMZ. Our study suggests structural differences across PARPi may contribute to differences in PARP selectivity and off-target activities, which along with distinct pharmacokinetic properties, may influence inhibitor-specific toxicities in patients.

Hematological toxicities in PARP inhibitors: A real-world study using FDA adverse event reporting system (FAERS) database

OBJECTIVE

Poly ADP-ribose polymerase inhibitors (PARPis) have significantly improved clinical effects in gynecological oncology. However, PARPis could also induce severe organ system toxicities, including the hematological system. Our study aimed to extensively characterize the hematological toxicities of PARPis based on the real-world data.

METHODS

Disproportionality analysis was used to evaluate the association between PARPis and hematotoxicity adverse events. Data were extracted from the US FDA Adverse Event Reporting System (FAERS) database between January 2015 and September 2021. The characteristics of PARPi-associated hematological toxicities, and the onset time and fatality proportion were further analyzed.

RESULTS

Out of 24,045 adverse events reports, 4088 hematotoxicity reports (17.00%) were analyzed, with a median age of 64.95 (interquartile range [IQR] 51-71) years. All PARPis were detected with positive safety signals of hematological toxicities in four detection methods. Unexpected significant adverse events such as lymphadenopathy, lymphoedema, and metastases to lymph nodes might also occur. The median time-to-onset was 28 (IQR 10-101) days and the fatality proportion of hematological toxicities with PARPis was 8.76%, with a statistical difference in different PARPis.

CONCLUSION

Hematological toxicities caused by PARPis preferred to occur early and might result in serious outcomes. Early identification and response to the PARPi-related hematological toxicities were important and further basic research were needed to confirm the mechanism of results in this study.