Real-World Delivery of Rucaparib to Patients with Ovarian Cancer: Recommendations Based on an Integrated Safety Analysis of ARIEL2 and Study 10

Poly(ADP-ribose) polymerase inhibitors in the treatment landscape of triple-negative breast cancer (TNBC)

OBJECTIVE

Chemotherapy is the mainstay for triple-negative breast cancer (TNBC) patients. Over the years, the use of chemotherapy for these patients has demonstrated many adversities, including toxicity and resistance, which suggested the need to develop novel alternative therapeutic options, such as poly(ADP-ribose) polymerase inhibitors (PARPi). Herein, we provide an overview on PARPi, mechanisms of action and the role of biomarkers in PARPi sensitivity trials, clinical advances in PARPi therapy for TNBC patients based on the most recent studies and findings of clinical trials, and challenges that prevent PARP inhibitors from achieving high efficacy such as resistance and overlapping toxicities with other chemotherapies.

DATA SOURCES

Searching for relevant articles was done using PubMed and Cochrane Library databases by using the keywords including TNBC; chemotherapy; PARPi; BRCA; homologous recombination repair (HRR). Studies had to be published in full-text in English in order to be considered.

DATA SUMMARY

Although PARPi have been used in the treatment of local/metastatic breast malignancies that are HER2 negative and has a germline BRCA mutation, several questions are still to be answered in order to maximize the clinical benefit of PARP inhibitors in TNBC treatment, such as questions related to the optimal use in the neoadjuvant and metastatic settings as well as the best combinations with various chemotherapies.

CONCLUSIONS

PARPi are emerging treatment options for patients with gBRCA1/2 mutations. Determining patients that are most likely to benefit from PARPi and identifying the optimal treatment combinations with high efficacy and fewer side effects are currently ongoing.

Managing Adverse Effects Associated With Poly (ADP-ribose) Polymerase Inhibitors in Ovarian Cancer: A Synthesis of Clinical Trial and Real-World Data

The use of poly (ADP-ribose) polymerase (PARP) inhibitor therapy is standard care in the management of patients with various malignancies including ovarian, breast, prostate, and pancreatic cancers. PARP inhibitors have been approved in different settings for patients with specific hereditary pathogenic variants, most notably homologous recombination repair pathways such as BRCA1 and BRCA2 genes. The vast experience with PARP inhibitors (olaparib, niraparib, rucaparib) has been in the management of epithelial ovarian cancer. There have not been any head-to-head comparisons of PARP inhibitors in randomized trials, and we can only perform cross-comparison on the basis of the reported literature. The three approved PARP inhibitors share several common adverse effects because of a class effect including nausea, fatigue, and anemia, but there are notable differences likely because of variations in their poly-pharmacology and off-target effects. Finally, patients included in clinical trials are often younger with a good performance status and less comorbidities than the real-world population, and hence, the potential benefits and adverse effects may not be superimposable. In this review, we describe these differences and discuss strategies to mitigate and manage adverse side effects effectively.

Genitourinary Cancer: Updates on Treatments and Their Impact on the Kidney

Genitourinary cancers are diverse in their presentation, prevalence, and mortality risk. Although there have been significant advancements in medical (eg, immune checkpoint inhibitors and tyrosine kinase inhibitors) and surgical treatments of genitourinary cancers, patients are still at risk for chronic kidney disease, hypertension, and electrolyte derangements in the short and long term. In addition, pre-existing kidney disease may increase the risk of developing some genitourinary cancers. This review focuses on the kidney-related effects of treatments for renal cell carcinoma and bladder and prostate cancers.

Review of Toxicities of PARP Inhibitors in Metastatic Castrate Resistant Prostate Cancer

There is emerging evidence for the use of poly (ADP-ribose) polymerase inhibitors (PARPi) in patients with mCRPC with patients harboring germline or somatic mutations deriving clinical benefit. However, the toxicity profile of PARPi in mCRPC is not well established. In March 2022 a literature search was conducted across 4 databases - Medline, PubMed, Cochrane Library and Embase. In total, 14 relevant studies were identified cumulating in 2066 patients that were treated with PARPi. The overall ORR to PARPi alone or in combination with other therapy was 37% (246/666). In 5trials that investigated PARPi alone, the ORR was 39% (141/361). Treatment emergent adverse events (TEAEs) of any grade were reported in 96% (1034/1080) in PARPi treatment arms. TEAEs of grade >= 3 were reported in 57% (611/1080). 45% (457/1006) experienced treatment interruption whilst 31% (310/989) required dose reductions. 11% (114/1006) of patients had their treatment discontinued directly as the result of toxicity associated with the trial medications. The most common hematological toxicity was anemia, reported in 490/1160 (42%) patients. and lowered white blood cell count were the next 2most common toxicities, reported in 186/655 (28%) and 133/729 (18%) respectively. The 3most common non-hematological toxicities reported were nausea, fatigue and anorexia reported in 440/1013 (43%), 340/1013 (34%) and 274/1013 (27%) patients respectively. Overall, TRAEs associated with individual PARPi are still emerging with hematological toxicities being most apparent. Further toxicities will be informed from future clinical trials to allow improved treatment selection, education and management of toxicities in prostate cancer.

Current status and progress in using radiolabelled PARP-1 inhibitors for imaging PARP-1 expression in tumours

Poly(ADP-ribose) polymerase-1 (PARP-1) is a key enzyme in the DNA repair process, and the overexpression of PARP-1 in several tumours makes this enzyme a promising molecular target. Recently, several PARP-1 inhibitors, such as olaparib, rucaparib, niraparib and talazoparib, have been clinically approved as anticancer drugs. Several of these inhibitors have been radiolabelled for noninvasive imaging of PARP-1 expression in several types of tumours. In this review, the background and progress for using various radiolabelled PARP-1 inhibitors for cancer diagnosis are discussed and future development directions are proposed.

Guidelines for Management of Treatment-Emergent Adverse Events During Rucaparib Treatment of Patients with Metastatic Castration-Resistant Prostate Cancer

Purpose

The US Food and Drug Administration has recently granted accelerated approval of the poly(ADP-ribose) polymerase (PARP) inhibitor rucaparib as treatment for men with metastatic castration-resistant prostate cancer (mCRPC) associated with a deleterious germline or somatic BRCA1 or BRCA2 (BRCA) alteration. As the safety profile of this new addition to the mCRPC treatment landscape may be unfamiliar to clinicians and patients, we summarize the data from the literature and provide practical guidelines for the management of treatment-emergent adverse events (TEAEs) that may occur during rucaparib treatment.

Materials and Methods

Safety data were identified from PubMed and congress publications of trials involving men with mCRPC treated with oral rucaparib monotherapy (600 mg twice daily). Management guidelines for TEAEs were developed based on trial protocols, prescribing information, oncology association guidance, and the authors’ clinical experience.

Results

In clinical trials of men with mCRPC who received rucaparib (n = 193), TEAEs observed were consistent with that of other PARP inhibitors. The most frequent any-grade TEAEs included gastrointestinal events, asthenia/fatigue, anemia, increased alanine/aspartate aminotransferase, rash, and thrombocytopenia; the most frequent grade ≥3 TEAE was anemia. The majority of TEAEs were self-limiting and did not require treatment modification or interruption. Here, we provide recommendations on management of the most common TEAEs reported with rucaparib as well as other TEAEs of interest.

Conclusion

Rucaparib’s recent approval for treatment of BRCA-mutant mCRPC is practice changing. Proper management of TEAEs will allow maximum treatment benefit for patients receiving rucaparib.

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

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

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

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

Management of nausea and vomiting from poly(ADP-ribose) polymerase inhibitor therapy for advanced ovarian cancer

Poly(ADP-ribose) polymerase (PARP) inhibitors have rapidly emerged as a new class of daily oral chemotherapeutic agents that have the potential to dramatically alter the way in which primary peritoneal, fallopian tube and ovarian cancers are treated. However, the management of nausea and vomiting, the most common toxicities incurred by these agents, remains poorly understood. The purpose of this review is to provide an overview of current guidelines, antiemetic agents and management steps for patients experiencing nausea and vomiting associated with the use of PARP inhibitors.

Management of Adverse Events During Rucaparib Treatment for Relapsed Ovarian Cancer: A Review of Published Studies and Practical Guidance

The poly(ADP-ribose) polymerase inhibitor rucaparib is approved as monotherapy in the treatment and maintenance settings for women with relapsed ovarian cancer in the European Union and the United States. We review the safety profile of rucaparib in both settings and provide recommendations for the clinical management of the main adverse events (AEs) that may occur during rucaparib treatment. We searched PubMed and congress proceedings for safety data on oral rucaparib monotherapy (600 mg twice daily) from clinical trials involving patients with relapsed ovarian cancer. AE management guidance was developed from clinical trial protocols, rucaparib prescribing information, oncology association guidelines, and author experience. The most frequent any-grade treatment-emergent AEs (TEAEs) included gastrointestinal symptoms, asthenia/fatigue, dysgeusia, anemia/decreased hemoglobin, and increased alanine/aspartate aminotransferase. Across clinical trials, 61.8% of patients had one or more grade 3 or higher TEAEs. Clinicians should employ close follow-up for TEAEs, particularly early in treatment, and educate patients about expected TEAEs and methods for their monitoring and management (e.g., antiemetics for nausea/vomiting, transfusions for hematologic TEAEs, or dose interruptions/reductions for moderate/severe TEAEs). Overall, 16.2% of patients discontinued rucaparib due to TEAEs. Management of AEs that may occur during rucaparib treatment is crucial for patients to obtain optimal clinical benefit by remaining on therapy and to avoid their detrimental impact on quality of life.