Impact of detecting plasma EGFR mutations with ultrasensitive liquid biopsy in outcomes of NSCLC patients treated with first- or second-generation EGFR-TKIs

BACKGROUND

Few trials have evaluated the utility of liquid biopsies to detect epidermal growth factor receptor mutations (EGFRm) at the time of response evaluation and its association with the clinical characteristics and outcomes of non-small-cell lung cancer (NSCLC) patients.

OBJECTIVE

This study aimed to evaluate, in a real-world clinical setting, the prevalence of plasma EGFRm and its association with the clinical characteristics, response and survival outcomes of NSCLC patients under treatment with EGFR-tyrosine kinase inhibitors (EGFR-TKIs).

METHODS

This observational study enrolled advanced or metastatic NSCLC patients, with confirmed tumor EGFRm, receiving treatment with first- or second-generation EGFR-TKIs. Blood samples for the detection of plasma EGFRm were collected at the time of response evaluation and processed using the Target Selector™ assay. The main outcomes were the detection rate of plasma EGFRm, median Progression-Free Survival (PFS) and Overall Survival (OS) according to plasma EGFR mutational status.

RESULTS

Of 84 patients, 50 (59.5%) had an EGFRm detected in plasma. After a median follow-up of 21.1 months, 63 patients (75%) had disease progression. The detection rate of plasma EGFRm was significantly higher in patients with disease progression than in patients with partial response or stable disease (68.3% versus 33.3%; P< 0.01). PFS and OS were significantly longer in patients without plasma EGFRm than among patients with plasma EGFRm (14.3 months [95% CI, 9.25-19.39] vs 11.0 months [95% CI, 8.61-13.46]; P= 0.034) and (67.8 months [95% CI, 39.80-95.94] vs 32.0 months [95% CI, 17.12-46.93]; P= 0.006), respectively. A positive finding in LB was associated with the presence of ⩾ 3 more metastatic sites (P= 0.028), elevated serum carcinoembryonic (CEA) at disease progression (P= 0.015), and an increase in CEA with respect to baseline levels (P= 0.038).

CONCLUSIONS

In NSCLC patients receiving EGFR-TKIs, the detection of plasma EGFRm at the time of tumor response evaluation is associated with poor clinical outcomes.

Half-dose olaparib reduction: Safe and efficient dose in multi-treated Mexican ovarian cancer patients

e17101

Background: Ovarian cancer (OC) is the most common gynecological cancer worldwide, and in Mexico stands as the 2nd gynecological cancer-related death cause with 4,759 new cases yearly. PARP inhibitors in BRCA1/2 mutated patients offer disease control after response to chemotherapy with few side effects and minimal impact on quality of life. The primary objective of this study was to evaluate the clinical benefit of Olaparib half-dose reduction in multi-treated Mexican OC patients. Methods: Nineteen OC BRCA1/2 positive patients were enrolled (Nov 2016-Dec 2018), at the Instituto Nacional de Cancerología, Mexico. Eligible patients had received > 2 previous platinum-based lines. Olaparib dose was 800 mg/day, as maintenance therapy after complete or partial response. Half-dose administration was allowed in grade 3 toxicity events. Median PFS curves were estimated by the Kaplan–Meier method. Results: The most common mutation in OC patients was BRCA1 (78.9%), four patients had founder mutation (Del9-12). Eleven patients (57.9%) received Olaparib in ≥4 lines. Nine patients required dose adjustment following hematological (42.1%) and gastrointestinal toxicity (5.2%). There was not statistical differences between complete-dose and half-dose administration groups. However patients with founder BRCA1 mutation did not require dose adjustment ( P= 0.033) and multi-treated (≥4 lines) patients were more susceptible to develop hematological toxicity ( P= 0.030). The median PFS was 12.02 months, patients HGSP histology had a better PFS compared with endometroid histology (14.8 Vs 5.19; P= 0.020). BRCA1 founder mutated patients had a better PFS compared with other BRCA mutations (NR Vs 11.30; P= 0.050). The median PFS in first, second and third or more recurrence was NR Vs 14.8 Vs 8.3; P= 0.050. We did not find statistical difference in the PFS in half-dose reduction compared with complete-dose groups (9.6 Vs NR; P= 0.221). Conclusions: We provide evidence that using Olaparib in first and second recurrence had better outcome compared with third or more recurrence. However the recommended dose exhibits a high toxicity profile; therefore half-dose reduction in multi-treated patients needs to be suggested in Olaparib OC guidelines as a safety and effective strategy.

Clinical benefit of bevacizumab in Mexican ovarian cancer patients according to the intention of treatment by the oncologist

e17097

Background: Ovarian cancer (OC) is the first cause of gynecological cancer, and the fifth cause of women cancer-death in US. In Mexico, more than 4,500 new cases of ovarian cancer are diagnosed yearly and it represents the second cause of gynecological cancer mortality. Bevacizumab (BVZ) is an antiangiogenic antibody that has been approved for first-line and recurrence therapy in OC patients. The aim of the study was to evaluate the clinical benefit of BVZ in different lines of treatment in Mexican OC patients. Methods: A total of 94 OC patients treated with BVZ were recruited at the Ovarian Cancer Program of the Instituto Nacional de Cancerología, from February 2012 to September 2018. Clinicopathological characteristics and toxicity was correlated with line of treatment. PFS curves were estimated by the Kaplan–Meier method, while comparisons among groups were analyzed with log-rank or Breslow tests. Results: Most of the patients were stage IIIC (69.1%) with HGSP histology (73.4%). 24 patients (25.5%) received BVZ as first-line treatment before debulking surgery (50% for suboptimal and 45.8% for optimal cytoreduction). 48 patients (51.1%) received BVZ for second-line (72.9% after a platinum-resistant and 27.1% after a platinum-sensitive recurrence) and 22 patients (23.4%) for three or more lines of treatment. Venous thromboembolic events (VTE) were more frequent in multi-treated patients ( P= 0.030). The median PFS was 23.7, 11.7 and 5.8 months for first, second and third or more lines, respectively. Patients with optimal debulking surgery had a better PFS compared with suboptimal and BVZ in first-line patients (24.8 vs 20.9; P= 0.050). Patients with BVZ in second-line who are a platinum-sensitive recurrence had better PFS compared to those with a platinum-resistant disease (15.1 vs 7.6; P= 0.040). Conclusions: OC patients had clinical benefit from treatment with BVZ when used as first-line and first recurrence treatments. The use of BVZ for third or later line treatment has a questionable benefit and is associated with a higher rate of VTE. Also, we highlight that 77% of the patients had the greatest-benefit while 33% had limited-benefit.