A phase I study of TAK-659 and paclitaxel in patients with taxane-refractory advanced solid tumors.

BACKGROUND: Paclitaxel resistance limits durability of response in patients with initial clinical benefit. Overexpression of spleen tyrosine kinase (SYK) has been proposed as a possible resistance mechanism. This phase I trial evaluated the safety and preliminary activity of the SYK inhibitor TAK-659 combined with paclitaxel in patients with advanced taxane-refractory solid tumors. PATIENTS AND METHODS: Patients with advanced solid tumors and prior progression on taxane-based therapy received intravenous infusion of paclitaxel on days 1, 8, and 15 plus oral TAK-659 daily in 28-day cycles. The dose-escalation phase included six cohorts treated at different dose levels; the dose-expansion phase included patients with ovarian cancer treated at the highest dose level. Toxicity was graded using the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0. Efficacy was evaluated using Response Evaluation Criteria in Solid Tumors version 1.1. RESULTS: Our study included 49 patients. Maximum tolerated dose was not reached, but higher rates of adverse events were observed at higher dose levels. There were no treatment-related deaths. The most common treatment-related adverse events of any grade were increased aspartate aminotransferase (n = 31; 63%), increased alanine aminotransferase (n = 26; 53%), decreased neutrophil count (n = 26; 53%), and decreased white blood cell count (n = 26; 53%). Most adverse events were either grade 1 or 2. In the 44 patients with evaluable disease, 12 (27%) had stable disease as the best overall response, including three patients with prolonged stable disease, and 4 patients (9%) achieved a partial response. CONCLUSIONS: The combination of paclitaxel and TAK-659 showed preliminary activity possibly overcoming resistance to taxane-based therapy as well as a tolerable safety profile in patients with advanced solid tumors.

HER2-low expression in patients with advanced or metastatic solid tumors.

BACKGROUND: Human epidermal growth factor receptor 2 (HER2)-low is a newly defined category with HER2 1+ or 2+ expression by immunohistochemistry (IHC) and lack of HER2 gene amplification measured by in situ hybridization (ISH). Much remains unknown about the HER2-low status across tumor types and changes in HER2 status between primary and metastatic samples. PATIENTS AND METHODS: HER2 expression by IHC was evaluated in 4701 patients with solid tumors. We have evaluated the HER2 expression by IHC and amplification by ISH in paired breast and gastric/gastroesophageal (GEJ) primary and metastatic samples. HER2 expression was correlated with ERBB2 genomic alterations evaluated by next-generation sequencing (NGS) in non-breast, non-gastric/GEJ samples. RESULTS: HER2 expression (HER2 IHC 1-3+) was found in half (49.8%) of the cancers, with HER2-low (1 or 2+) found in many tumor types: 47.1% in breast, 34.6% in gastric/GEJ, 50.0% in salivary gland, 46.9% in lung, 46.5% in endometrial, 46% in urothelial, and 45.5% of gallbladder cancers. The concordance evaluation of HER2 expression between primary and metastatic breast cancer samples showed that HER2 3+ remained unchanged in 87.1% with a strong agreement between primary and metastatic samples, with a weighted kappa (Κ) of 0.85 (95% confidence interval 0.79-0.91). ERBB2 alterations were identified in 117 (7.5%) patients with non-breast, non-gastric/GEJ solid tumors who had NGS testing. Of 1436 patients without ERBB2 alterations, 512 (35.7%) showed any level HER2 expression by IHC. CONCLUSION: Our results show that HER2-low expression is frequently found across tumor types. These findings suggest that many patients with HER2-low solid tumors might benefit from HER2-targeted therapies.

Phase Ib study of eprenetapopt (APR-246) in combination with pembrolizumab in patients with advanced or metastatic solid tumors.

BACKGROUND: We conducted a phase I, multicenter, open-label, dose-finding, and expansion study to determine the safety and preliminary efficacy of eprenetapopt (APR-246) combined with pembrolizumab in patients with advanced/metastatic solid tumors (ClinicalTrials.gov NCT04383938). PATIENTS AND METHODS: For dose-finding, requirements were non-central nervous system primary solid tumor, intolerant to/progressed after ≥1 line of treatment, and eligible for pembrolizumab; for expansion: (i) gastric/gastroesophageal junction tumor, intolerant to/progressed after first-line treatment, and no prior anti-programmed cell death receptor-1 (PD-1)/programmed death-ligand 1 (PD-L1) therapy; (ii) bladder/urothelial tumor, intolerant to/progressed after first-line cisplatin-based chemotherapy, and no prior anti-PD-1/PD-L1 therapy; (iii) non-small-cell lung cancer (NSCLC) with previous anti-PD-1/PD-L1 therapy. Patients received eprenetapopt 4.5 g/day intravenously (IV) on days 1-4 with pembrolizumab 200 mg IV on day 3 in each 21-day cycle. Primary endpoints were dose-limiting toxicity (DLT), adverse events (AEs), and recommended phase II dose (RP2D) of eprenetapopt. RESULTS: Forty patients were enrolled (median age 66 years; range 27-85) and 37 received eprenetapopt plus pembrolizumab. No DLTs were reported and the RP2D for eprenetapopt in combination was 4.5 g/day IV on days 1-4. The most common eprenetapopt-related AEs were dizziness (35.1%), nausea (32.4%), and vomiting (29.7%). AEs leading to eprenetapopt discontinuation occurred in 2/37 patients (5.4%). In efficacy-assessable patients (n = 29), one achieved complete response (urothelial cancer), two achieved partial responses (NSCLC, urothelial cancer), and six patients had stable disease. CONCLUSIONS: The eprenetapopt plus pembrolizumab combination was well tolerated with an acceptable safety profile and showed clinical activity in patients with solid tumors.

PIK3CA mutations in plasma circulating tumor DNA predict survival and treatment outcomes in patients with advanced cancers.

BACKGROUND: Oncogenic mutations in PIK3CA are prevalent in diverse cancers and can be targeted with inhibitors of the phosphoinositide-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway. Analysis of circulating tumor DNA (ctDNA) provides a minimally invasive approach to detect clinically actionable PIK3CA mutations. PATIENTS AND METHODS: We analyzed PIK3CA hotspot mutation frequency by droplet digital PCR (QX 200; BioRad) using 16 ng of unamplified plasma-derived cell-free DNA from 68 patients with advanced solid tumors (breast cancer, n = 41; colorectal cancer, n = 13; other tumor types, n = 14). Results quantified as variant allele frequencies (VAFs) were compared with previous testing of archival tumor tissue and with patient outcomes. RESULTS: Of 68 patients, 58 (85%) had PIK3CA mutations in tumor tissue and 43 (74%) PIK3CA mutations in ctDNA with an overall concordance of 72% (49/68, κ = 0.38). In a subset analysis, which excluded samples from 26 patients known not to have disease progression at the time of sample collection, we found an overall concordance of 91% (38/42; κ = 0.74). PIK3CA-mutated ctDNA VAF of ≤8.5% (5% trimmed mean) showed a longer median survival compared with patients with a higher VAF (15.9 versus 9.4 months; 95% confidence interval 6.7-17.1 months; P = 0.014). Longitudinal analysis of ctDNA in 18 patients with serial plasma collections (range 2-22 time points, median 5) showed that those with a decrease in PIK3CA VAF had a longer time to treatment failure (TTF) compared with patients with an increase or no change (10.7 versus 2.6 months; P = 0.048). CONCLUSIONS: Detection of PIK3CA mutations in ctDNA is concordant with testing of archival tumor tissue. Low quantity of PIK3CA-mutant ctDNA is associated with longer survival and a decrease in PIK3CA-mutant ctDNA on therapy is associated with longer TTF.

Expanded analysis of secondary germline findings from matched tumor/normal sequencing identifies additional clinically significant mutations.

BACKGROUND: Next-generation sequencing (NGS) for tumor molecular profiling can reveal secondary germline pathogenic and likely pathogenic variants (LPV/PV). The American College of Medical Genetics (ACMG) recommends return of secondary results for a subset of 59 genes, but other genes with evidence of clinical utility are emerging. We previously reported that 4.3% of patients who underwent NGS of a targeted panel of 201 genes had LPV/PV based on the ACMG list. Here we report the frequency of additional germline cancer-related gene variants and discuss their clinical utility. PATIENTS AND METHODS: Matched tumor and germline DNA NGS of a targeted panel of 201 genes was performed in a research laboratory on samples from 1000 patients with advanced or metastatic solid tumors enrolled in a molecular testing protocol (NCT01772771). The frequency of germline LPV/PV in 54 cancer-related genes, beyond the genes in ACMG list, were analyzed. RESULTS: Among 1000 patients who underwent tumor/normal DNA sequencing, 46 (4.6%) were found to have a germline LPV/PV in the following genes: AR-(5), ATM-(4), BAP1-(1), CDH1-(1), CDKN2A-(1), CHEK1-(2), CHEK2-(10), EGFR-(1), ERCC3-(4), ERCC5-(1), HNF1B-(1), HRAS-(1), MITF-(4), MLL3-(1), NF1-(3), PKHD1-(4), PTCH1-(1), and SMARCA4-(1). Thus, a total 8.7% of patients had an LPV/PV with 2 patients having 2 concomitant germline LPV/PV. Five mutations in high-penetrance hereditary cancer predisposition genes were selected to be returned to patients or their representatives: BAP1, CDH1, CDKN2A, EGFR, and SMARCA4. CONCLUSIONS: Broader genomic testing is likely to identify additional secondary pathogenic germline alterations, some with potential clinical utility for return to patients and their relatives. The recommended genes for which germline results should be returned are continually changing, warranting continued study.