Pivotal (Spain)

Simple SummaryGenomic instability (GI) is a transversal phenomenon in oncology, constituting a hallmark of cancer. In gynecological malignancies, the predictive value of GI has been described and is mainly caused by alterations in the homologous recombination repair (HRR) genes, such as BRCA1/2. The POLA clinical trial constitutes an ideal substrate used to study the correlation between GI and response to combined therapy of lurbinectedin plus olaparib in solid tumors. In this context, we developed an approach based on next-generation sequencing, capable of shedding information about Copy Number Variations (CNV) as a surrogate of GI and genotyping of homologous recombination repair genes. Additionally, some algorithms used to extract GI parameters were tested and benchmarked, selecting the most informative mutational and GI features as potential predictive biomarkers for the drug combination explored in the POLA trial.We hypothesized that the combination of olaparib and lurbinectedin maximizes DNA damage, thus increasing its efficacy. The POLA phase 1 trial established the recommended phase 2 dose of lurbinectedin as being 1.5 mg (day 1) and that of olaparib as being 250 mg/12 h (days 1–5) for a 21-day cycle. In phase 2, we explore the efficacy of the combination in terms of clinical response and its correlation with mutations in the HRR genes and the genomic instability (GI) parameters. Results: A total of 73 patients with high-grade ovarian (n = 46), endometrial (n = 26), and triple-negative breast cancer (n = 1) were treated with lurbinectedin and olaparib. Most patients (62%) received ≥3 lines of prior therapy. The overall response rate (ORR) and disease control rate (DCR) were 9.6% and 72.6%, respectively. The median progression-free survival (PFS) was 4.54 months (95% CI 3.0–5.2). Twelve (16.4%) patients were considered long-term responders (LTR), with a median PFS of 13.3 months. No clinical benefit was observed for cases with HRR gene mutation. In ovarian LTRs, although a direct association with GI and a total loss of heterozygosity (LOH) events was observed, the association did not reach statistical significance (p = 0.055). Globally, the total number of LOHs might be associated with the ORR (p =0.074). The most common grade 3–4 toxicities were anemia and thrombocytopenia, in 6 (8.2%) and 3 (4.1%) patients, respectively. Conclusion: The POLA study provides evidence that the administration of lurbinectedin and olaparib is feasible and tolerable, with a DCR of 72.6%. Different GI parameters showed associations with better responses.

BRAF V600 mutations have been found in 1–2% of non-small-cell lung cancer (NSCLC) patients, with Food and Drug Administration (FDA) approved treatment of dabrafenib plus trametinib and progression free survival (PFS) of 10.9 months. However, 50–80% of BRAF mutations in lung cancer are non-V600, and can be class II, with intermediate to high kinase activity and RAS independence, or class III, with impaired kinase activity, upstream signaling dependence, and consequently, sensitivity to receptor tyrosine kinase (RTK) inhibitors. Plasma cell-free DNA (cfDNA) of 185 newly diagnosed advanced lung adenocarcinoma patients (Spanish Lung Liquid versus Invasive Biopsy Program, SLLIP, NCT03248089) was examined for BRAF and other alterations with a targeted cfDNA next-generation sequencing (NGS) assay (Guardant360®, Guardant Health Inc., CA, USA), and results were correlated with patient outcome. Cell viability with single or combined RAF, MEK, and SHP2 inhibitors was assessed in cell lines with BRAF class I, II, and III mutations. Out of 185 patients, 22 had BRAF alterations (12%) of which seven patients harbored amplifications (32%) and 17 had BRAF mutations (77%). Of the BRAF mutations, four out of 22 (18%) were V600E and 18/22 (82%) were non-V600. In vitro results confirmed sensitivity of class III and resistance of class I and II BRAF mutations, and BRAF wild type cells to SHP2 inhibition. Concomitant MEK or RAF and SHP2 inhibition showed synergistic effects, especially in the class III BRAF-mutant cell line. Our study indicates that the class of the BRAF mutation may have clinical implications and therefore should be defined in the clinical practice and used to guide therapeutic decisions.

Clinical and Translational Oncology.

TPS5089Background: The management of metastatic castration resistant prostate cancer (mCRPC) has been revolutionized with the approval of several agents improving overall survival. However, despite...

Immunotherapy increases overall response rate (ORR) and overall survival (OS) in patients with non-small-cell lung cancer (NSCLC). Prognostic and predictive factors are a high need. Retrospective review of NSCLC patients treated with nivolumab was performed. Analyzed variables included age, sex, stage, performance status (PS), location of metastases, presence of tumour-related symptoms and comorbidities, number of metastasis locations, previous chemotherapy, anti-angiogenic and radiotherapy treatments, and analytical data from the standard blood count and biochemistry. A total of 175 patients were included. Median age was 61.5years, 73.1% were men, 77.7% were ECOG-PS 0-1, and 86.7% were included with stage IV disease. Histology was non-squamous in 77.1%. Sixty-five received nivolumab in second line (37.1%). Thirty-eight patients had brain metastasis (22%), and 39 (22.3%) liver metastasis and 126 (72%) had more than one metastatic location. The ORR was 15.7% with median Progression free survival (PFS) 2.8months and median OS 5.81months. Stage III vs IV and time since the beginning of the previous line of treatment≥6 vs<6months were associated with better response. PS 2, time since the previous line of treatment<6 vs≥6months, and more than one metastatic location were independently associated with shorter OS in multivariable analysis (7.8 vs 2.7months, 11.2 vs 4.6months, and 9.4 vs 5.1month). Finally, time since the previous treatment<6 vs≥6months and more than one metastatic location were independently associated with shorter PFS in multivariable analysis (4.3 vs 2.3months and 4.7 vs 2.3months). Poor PS, short period of time since the previous treatment, and more than one metastatic location were associated with poorer prognostic.

BIM is a proapoptotic protein that initiates apoptosis triggered by EGFR tyrosine kinase inhibitors (TKI). mTOR negatively regulates apoptosis and may influence response to EGFR TKI. We examined mRNA expression of BIM and MTOR in 57 patients with EGFR-mutant NSCLC from the EURTAC trial. Risk of mortality and disease progression was lower in patients with high BIM compared with low/intermediate BIM mRNA levels. Analysis of MTOR further divided patients with high BIM expression into two groups, with those having both high BIM and MTOR experiencing shorter overall and progression-free survival to erlotinib. Validation of our results was performed in an independent cohort of 19 patients with EGFR-mutant NSCLC treated with EGFR TKIs. In EGFR-mutant lung adenocarcinoma cell lines with high BIM expression, concomitant high mTOR expression increased IC50 of gefitinib for cell proliferation. We next sought to analyse the signalling pattern in cell lines with strong activation of mTOR and its substrate P-S6. We showed that mTOR and phosphodiesterase 4D (PDE4D) strongly correlate in resistant EGFR-mutant cancer cell lines. These data suggest that the combination of EGFR TKI with mTOR or PDE4 inhibitors could be adequate therapy for EGFR-mutant NSCLC patients with high pretreatment levels of BIM and mTOR.

11027 Background: Progression-free survival (PFS) is short in NSCLC driven by EGFR mutations treated with erlotinib alone, due to crosstalk with other signaling pathways that can cause secondary dependency. ROR1 knockdown inhibited the growth of NCI-H1975 cells (with EGFR L858R and T790M mutations). A pro-survival function for ROR1/MEK/ERK signaling has been demonstrated, with cooperation with AKT. In a subset of 95 p in the EURTAC trial (clinicaltrials.gov NCT00446225), 65% had pre-treatment T790M mutations. We have assessed ROR1 expression in 45 of these 95 p. Methods: The T790M mutation was determined by Taqman with a PNA to inhibit amplification of the wild-type (wt) allele. Tumor samples were run in octuplicates; this method can detect 1 mutated allele among 10,000 wt alleles. ROR1 mRNA expression was examined by quantitative RT-PCR and categorized by terciles. p were classified as having low/intermediate or high ROR1 expression. The impact of ROR1 expression on outcome was examined in all 45 p and in a subset of 15 p with concomitant T790M mutations. Results: Median age 65; 68.9% female; 57.8% never-smokers; 95.6% ECOG PS &lt;2; 91.1% adenocarcinoma; 68.9% exon 19 deletion. No differences in baseline characteristics were observed according to ROR1 expression levels. 24 p (53.3%) were treated with erlotinib and 21 p (46.7%) with chemotherapy. 10 (41.7%) erlotinib-treated p and 6 (28.6%) chemotherapy-treated p had ROR1 mRNA levels in the top tercile. Among erlotinib-treated p, response rate was 40% for p with high ROR1 levels vs 71.4% for p with low/intermediate levels (P=0.0918). Among chemotherapy-treated p, only p with low ROR1 levels responded (6.7%). PFS was 11.8 months (m) for erlotinib-treated p with low/intermediate ROR1 levels vs 5.8 m for p with high levels. PFS for chemotherapy-treated p was 5.6 and 9 m, respectively (P=0.033). Among 15 erlotinib-treated p with concomitant T790M mutations, PFS was10.8 m for p with low/intermediate ROR1 levels vs 2.7 for p with high levels (P=0.0174). Conclusions: HighROR1 expression significantly limits PFS in p with T790M mutations. ROR1-directed therapies can enhance the efficacy of erlotinib in EGFR-mutant NSCLC p overexpressing ROR1. Clinical trial information: NCT00446225.