Olaparib treatment in older patients with ovarian cancer: need for 'real-world' data beyond clinical trials

Efficacy and Safety of Niraparib as First-Line Maintenance Treatment for Patients with Advanced Ovarian Cancer: Real-World Data from a Multicenter Study in China

BACKGROUND

Poly (ADP-ribose) polymerase (PARP) inhibitors are a new maintenance therapy option for patients with ovarian cancer (OC).

OBJECTIVE

To evaluate the efficacy and influencing factors of the novel PARP inhibitor niraparib for maintenance treatment of Chinese patients with advanced OC.

PATIENTS AND METHODS

In this retrospective multicenter real-world study patients with advanced OC from 15 hospitals throughout China were enrolled. The primary endpoint was progression-free survival (PFS) and the secondary endpoints included the time to treatment discontinuation and safety. Least Absolute Shrinkage and Selection Operator (LASSO) regression was used to identify possible risk factors for PFS, after which a prediction model was established to evaluate the likelihood of achieving an 18-month PFS. The relationship between the dose of niraparib and PFS was also evaluated.

RESULTS

The PFS rates of 199 patients at 6, 12, 18, 24, and 30 months were 87.4%, 75.9%, 63.6%, 56.1%, and 51.8%, respectively. LASSO regression model revealed that only age < 65 years (P = 0.011), BRCA mutations (P < 0.001), and R0 status after cytoreductive surgery (P = 0.01) were significant factors associated with prolonged PFS times. Based on the LASSO logistic regression analysis, a clinical prediction formula was developed: - 2.412 + 1.396Age≥65yr + 2.374BRCAwt + 1.387R1 + 0.793Interval≥12w + 0.178BMI>24kg/m2 which yielded a cut-off value of 0.091, an area under the curve (AUC) of 0.839 (0.763-0.916), a sensitivity of 94.3%, and an accuracy of 78.5%. A nomogram was then built to visualize the results. The major treatment-emergent adverse events of ≥ grade 3 included a platelet count decrease (19.1%), white blood cell count decrease (15.1%), neutrophil count decrease (13.1%), and anemia (18.6%). The 18-month PFS rates in patients treated with 200 mg niraparib were somewhat higher than in patients treated with 100 mg after 3-months of therapy.

CONCLUSIONS

For Chinese OC patients, niraparib, particularly at a 200 mg individual starting dose, was an effective therapy with easily manageable safety.

Efficacy and safety of maintenance olaparib and bevacizumab in ovarian cancer patients aged ≥65 years from the PAOLA-1/ENGOT-ov25 trial

BACKGROUND

The phase III PAOLA-1/ENGOT-ov25 study (NCT02477644) showed that addition of olaparib to bevacizumab maintenance improved progression-free survival (PFS) in patients with newly diagnosed advanced ovarian cancer. We evaluated maintenance olaparib plus bevacizumab in older patients in PAOLA-1.

METHODS

Baseline clinical and molecular data, and PFS, were compared between older (aged ≥65 years) and younger patients (<65 years). Factors associated with olaparib efficacy, and safety in age subgroups, were also assessed.

RESULTS

Of 806 randomised patients, 292 (36.2%) were ≥65 years. A lower proportion of older versus younger patients had an Eastern Cooperative Oncology Group performance status of 0 (61.0% versus 76.2%) and upfront surgery (42.0% versus 55.7%). Older patients were less likely to have a BRCA1/2 mutation (17.1% versus 36.7%) or homologous recombination deficiency-positive status (34.1% versus 55.7%). After median follow-up of 22.1 months, median PFS was 21.6 months with olaparib versus 16.6 months with placebo in the older population (hazard ratio [HR] 0.55, 95% confidence interval [CI] 0.41-0.75), comparable with the younger population (median 22.9 versus 16.9 months; HR 0.61, 95% CI 0.49-0.77). PFS benefits were observed in patients with a BRCA mutation or homologous recombination deficiency-positive tumours. Incidence of olaparib-related grade ≥3 adverse events in older patients was comparable with that of younger patients (36.8% versus 31.7%) although hypertension and anaemia were more common in older patients. No treatment-related deaths occurred in older patients receiving olaparib.

CONCLUSION

Older patients enrolled in PAOLA-1 achieved similar PFS benefits compared with younger patients, with a similar safety profile.

Association between Olaparib Exposure and Early Toxicity in BRCA-Mutated Ovarian Cancer Patients: Results from a Retrospective Multicenter Study

Factors associated with olaparib toxicity remain unknown in ovarian cancer patients. The large inter-individual variability in olaparib pharmacokinetics could contribute to the onset of early significant adverse events (SAE). We aimed to retrospectively analyze the pharmacokinetic/pharmacodynamic relationship for toxicity in ovarian cancer patients from “real life” data. The clinical endpoint was the onset of SAE (grade III/IV toxicity or dose reduction/discontinuation). Plasma olaparib concentration was assayed using liquid chromatography at any time over the dosing interval. Trough concentrations (CminPred) were estimated using a population pharmacokinetic model. The association between toxicity and clinical characteristics or CminPred was assessed by logistic regression and non-parametric statistical tests. Twenty-seven patients were included, among whom 13 (48%) experienced SAE during the first six months of treatment. Olaparib CminPred was the only covariate significantly associated with increased risk of SAE onset (odds ratio = 1.31, 95% CI = [1.10; 1.57], for each additional 1000 ng/mL). The ROC curve identified a threshold of CminPred = 2500 ng/mL for prediction of SAE onset (sensitivity/specificity 0.62 and 1.00, respectively). This study highlights a significant association between olaparib plasma exposure and SAE onset and identified the threshold of 2500 ng/mL trough concentration as potentially useful to guide dose adjustment in ovarian cancer patients.

Taking the next step in PARP-inhibitor clinical trials in older women with ovarian cancer - Staging the aging

•Older patients are still underrepresented in randomized controlled clinical trials.•Older patients receiving PARP-inhibitors tend to achieve shorter PFS, even those considered fit.•Older patients experience more side effects, than their younger counterparts.•Prospective "real-world" data is needed in unselected older women with ovarian cancer receiving PARP-inhibitors.