Pharmacokinetics and safety of olaparib tablets as monotherapy and in combination with paclitaxel: results of a Phase I study in Chinese patients with advanced solid tumours

Physiologically-based pharmacokinetic modeling for optimal dosage prediction of olaparib when co-administered with CYP3A4 modulators and in patients with hepatic/renal impairment

This study aimed to develop a physiologically-based pharmacokinetic (PBPK) model to predict the maximum plasma concentration (Cmax) and trough concentration (Ctrough) at steady-state of olaparib (OLA) in Caucasian, Japanese and Chinese. Furthermore, the PBPK model was combined with mean and 95% confidence interval to predict optimal dosing regimens of OLA when co-administered with CYP3A4 modulators and administered to patients with hepatic/renal impairment. The dosing regimens were determined based on safety and efficacy PK threshold Cmax (< 12,500 ng/mL) and Ctrough (772-2500 ng/mL). The population PBPK model for OLA was successfully developed and validated, demonstrating good consistency with clinically observed data. The ratios of predicted to observed values for Cmax and Ctrough fell within the range of 0.5 to 2.0. When OLA was co-administered with a strong or moderate CYP3A4 inhibitor, the recommended dosing regimens should be reduced to 100 mg BID and 150 mg BID, respectively. Additionally, the PBPK model also suggested that OLA could be not recommended with a strong or moderate CYP3A4 inducer. For patients with moderate hepatic and renal impairment, the dosing regimens of OLA were recommended to be reduced to 200 mg BID and 150 mg BID, respectively. In cases of severe hepatic and renal impairment, the PBPK model suggested a dosing regimen of 100 mg BID for OLA. Overall, this present PBPK model can determine the optimal dosing regimens for various clinical scenarios involving OLA.

Enhancing the anti-tumor response by combining DNA damage repair inhibitors in the treatment of solid tumors

The anti-cancer efficacy of anti-malignancy therapies is related to DNA damage. However, DNA damage-response mechanisms can repair DNA damage, failing anti-tumor therapy. The resistance to chemotherapy, radiotherapy, and immunotherapy remains a clinical challenge. Thus, new strategies to overcome these therapeutic resistance mechanisms are needed. DNA damage repair inhibitors (DDRis) continue to be investigated, with polyadenosine diphosphate ribose polymerase inhibitors being the most studied inhibitors. Evidence of their clinical benefits and therapeutic potential in preclinical studies is growing. In addition to their potential as a monotherapy, DDRis may play an important synergistic role with other anti-cancer therapies or in reversing acquired treatment resistance. Here we review the impact of DDRis on solid tumors and the potential value of combinations of different treatment modalities with DDRis for solid tumors.

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 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.

Olaparib maintenance monotherapy in Chinese patients with platinum-sensitive relapsed ovarian cancer: China cohort from the phase III SOLO2 trial

AIM

The phase III SOLO2 global study demonstrated the efficacy and safety of maintenance olaparib, a poly(adenosine diphosphate-ribose) polymerase inhibitor, in platinum-sensitive relapsed ovarian cancer patients with a BRCA mutation. This separate China cohort of SOLO2 investigated the efficacy and safety of maintenance olaparib in Chinese patients.

METHODS

Patients received olaparib (300 mg twice daily, oral, tablets) or matched placebo. Primary endpoint was investigator-assessed progression-free survival (Response Evaluation Criteria in Solid Tumors version 1.1). Safety and tolerability were also assessed.

RESULTS

Thirty-two patients were treated. Olaparib treatment led to an improvement in progression-free survival compared with placebo (hazard ratio = 0.44, 95% confidence interval: 0.17-1.19; median = 13.8 vs. 5.5 months). Results of secondary efficacy endpoints of time to first subsequent treatment/death and time to treatment discontinuation/death were consistent with progression-free survival results. Time to second progression/death and time to second subsequent treatment/death data were immature at data cutoff. The most common adverse events in the olaparib arm were nausea (81.8%), anemia (45.5%), and decreased appetite (36.4%). Grade ≥3 adverse events were experienced by 36.4% of olaparib and 10.0% of placebo patients. No adverse events led to discontinuation of treatment. There were six deaths (olaparib, five; placebo, one); one death in the olaparib arm was due to an unknown cause, all others were related to disease progression.

CONCLUSIONS

Efficacy and safety findings in the China SOLO2 cohort support the use of olaparib (300 mg twice daily) as maintenance treatment for Chinese patients with platinum-sensitive relapsed ovarian cancer and a BRCA mutation.

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.

Knockdown of SERPINE1 reverses resistance of triple‑negative breast cancer to paclitaxel via suppression of VEGFA

Breast cancer (BC) has a poor prognosis and a high number of visceral metastases. Serine protease inhibitor, clade E member 1 (SERPINE1) is a molecule involved in several human malignancies. However, it remains unknown if SERPINE1 plays a role in the development of taxane resistance in TNBC cells. In the present study, the role and mechanism of SERPINE1 in the development of paclitaxel (PTX) resistance in TNBC cells were investigated. A bioinformatics analysis of gene expression profiles in PTX-resistant cells indicated that SERPINE1 was significantly associated with PTX resistance. Furthermore, the levels of SERPINE1 mRNA and protein were higher in PTX-resistant cells with respect to those in PTX-sensitive parent cells. Knockdown of SERPINE1 significantly inhibited cell survival and induced cell apoptosis in vitro. In addition, SERPINE1 silencing led to downregulation of the key angiogenetic vascular endothelial growth factor A (VEGFA). Furthermore, suppression of SERPINE1 markedly attenuated tumor growth in vivo. Collectively, these findings indicated that SERPINE1 significantly contributed to the proliferation and apoptosis of TNBC cells by regulating VEGFA expression. The present study demonstrated SERPINE1 as an oncogene in PTX drug resistance of breast cancer, and revealed that it may serve as a possible target for treating BC.