A phase I safety and efficacy clinical trial of plocabulin and gemcitabine in patients with advanced solid tumors.

Plocabulin (Plo) induces depolymerization of tubulin fibers with disorganization and fragmentation of the microtubule network leading to mitosis. Plo combined with gemcitabine (Gem) showed synergistic anti-tumor activity in preclinical studies. This phase I trial evaluated the safety, pharmacokinetics (PK) and efficacy of Plo 10-min infusion plus Gem on Day 1 and 8 every 3-week in patients with advanced solid tumors. Fifty-seven patients were enrolled into 8 dose levels (DLs); 74%: females; 74%: ECOG performance status 1; median age: 62 years; median number of prior lines of therapy:3. Dose-limiting toxicities (DLT) in Cycle 1 were grade (G) 3 intestinal obstruction at the maximum tolerated dose (MTD), G3 peripheral sensory neuropathy (PSN), G3 abdominal pain, and G4 thrombocytopenia (1 patient each). The highest DL (DL8: Plo 10.5 mg/m2/Gem 1000 mg/m2) was the MTD. Accrual into DL7 (Plo 10.0 mg/m2/Gem 1000 mg/m2) was stopped before it was formally defined as the recommended dose (RD). Most common treatment-related adverse events (AEs) were fatigue (56%), nausea (55%), diarrhea (31%); G3/4 hematologic toxicities comprised anemia (35%), neutropenia (27%) and thrombocytopenia (17%). No treatment-related deaths occurred. PK parameters for Gem or dFdU at all DLs were in line with reference values from the literature. Six of 46 evaluable pts were responders (overall response rate:13%). Of note, 2 partial responses (PR) and 2 stable disease (SD) ≥ 4 months occurred among 13 pts with ovarian cancer. The combination of Plo and Gem is well tolerated. The MTD was Plo 10.5 mg/m2/Gem 1000 mg/m2. No PK drug-drug interaction was found. The most encouraging outcome occurred in ovarian cancer patients.

Outcomes Among Racial and Ethnic Minority Patients With Advanced Cancers in Phase 1 Trials: A Meta-Analysis.

Importance: Patients from racial and ethnic minority groups (eg, Asian, Hispanic, and non-Hispanic Black patients) have low representation in clinical trials, especially in phase 1 trials in cancer. These trials represent valuable options for patients with advanced cancer who experience disease progression with standard therapy. Objective: To determine whether the benefit of enrollment to phase 1 cancer trials extends to Asian, Hispanic, and non-Hispanic Black patients as much as it does for non-Hispanic White patients. Data Sources: Patient records at a single institution from January 1999 to December 2016 were reviewed. Treatment-related responses, toxic effects, and deaths were recorded. Study Selection: All phase 1 studies were included. Data Extraction and Synthesis: Data underwent independent extraction by multiple observers following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline. Main Outcomes and Measures: The primary outcome was overall survival (OS), assessed using univariate and multivariable time-to-event analyses. Results: A total of 738 patients (median [range], 60 [22-93] years; 467 [63.3] female) including 197 Hispanic patients (26.7%), 238 non-Hispanic Black patients (32.2%), and 282 non-Hispanic White patients (38.2%), were enrolled in 64 phase 1 trials, including 33 cytotoxic trials (51.5%), 21 biologic trials (32.8%), and 10 combined therapy trials (15.6%). The primary cancer diagnoses were colorectal (187 patients [25.3%]), ovarian (141 patients [19.1%]), lung (58 patients [7.9%]), uterine (49 patients [6.6%]), and breast (41 patients [5.6%]). Patients underwent a median (range) of 3 (0-13) therapies prior to trial enrollment. Among 558 patients evaluated for response, the clinical benefit rate (ie, stable disease plus response rates) was 49.1%, and the overall response rate was 6.5%. Grade 3 or 4 nonhematological toxic effects were observed in 27.8% (95% CI, 24.6%-31.3%) of patients and grade 3 or 4 hematological toxic effects were observed in 19.7% (95% CI, 17.0%-22.8%) of patients. The treatment-related mortality rate was 0.9% (95% CI, 0.4%-1.9%). Median OS was 9.6 (95% CI, 8.2-11.0) months among Hispanic patients, 8.3 (95% CI, 6.7-10.4) months among non-Hispanic Black patients, and 9.8 (95% CI, 8.5-11.4) months among non-Hispanic White patients (P = .13). In a multivariable analysis, age older than 60 years, Eastern Cooperative Oncology Group performance status score of 2 or greater, more than 2 metastatic sites, lactate dehydrogenase grade 1 or 2, grade 2 or greater low albumin, grade 1 or greater total bilirubin, and grade 2 or greater anemia were associated with worse prognosis, whereas leukocytosis greater than grade 1 was associated with better OS. Conclusions and Relevance: In this meta-analysis assessing outcomes in phase 1 cancer trials among patients from racial and ethnic minority groups, Hispanic and non-Hispanic Black patients had benefits similar to those of non-Hispanic White patients.

Erlotinib Treatment in Colorectal Cancer Suppresses Autophagy Based on KRAS Mutation.

The KRAS gene is mutated in approximately 45% of colorectal cancer patients. There are currently very few targeted treatments or therapies equipped to directly inhibit KRAS due to its unusual structural intricacies. Erlotinib, an EGFR inhibitor, has previously been demonstrated to reduce cell viability by inducing autophagy in lung cancer cell lines with varying EGFR mutations. In contrast to lung cancer cells, evidence is provided herein for the first time that erlotinib treatment in colorectal cancer (CRC) cell lines reduces autophagy and still results in decreased cell viability. However, the effects of erlotinib in CRC cell lines containing a wildtype KRAS gene were different than in cells carrying a mutant KRAS gene. We show that there is significantly more downregulation of autophagy in KRAS mutant CRC cells compared to KRAS wildtype cells, both at transcriptional and translational levels, suggesting that the KRAS mutation is advantageous for cancer growth, even in the presence of erlotinib. Cell viability results determined that KRAS wildtype CRC cells had significantly more cell death compared to KRAS mutant cells. Using patient mRNA datasets, we showed that there was a significant correlation between the presence of the KRAS mutation and the expression of autophagy proteins. Additionally, through molecular dynamics simulations, we develop a blueprint for KRAS and autophagy protein interaction and the impact of the KRAS mutation on autophagy protein regulation. Overall, this is the first report of erlotinib treatment in CRC cells that assesses autophagy, and we demonstrate that autophagy activity is downregulated in these cells. This effect is not only greater in cells carrying a KRAS mutation compared to wildtype cells, but the KRAS mutant cells also have increased cell viability compared to wildtype cells. We hypothesize that the difference in cell viability and autophagy expression between KRAS mutant and KRAS wildtype cells after treatment with erlotinib can be of therapeutic value to treat CRC patients carrying KRAS mutations.

Impact of carbamazepine on SMARCA4 (BRG1) expression in colorectal cancer: modulation by KRAS mutation status.

SMARCA4 is a gene traditionally considered a tumor suppressor. Recent research has however found that SMARCA4 likely promotes cancer growth and is a good target for cancer treatment. The drug carbamazepine, an autophagy inducer, was used on colorectal cancer cell lines, HCT1116 and Hke3 (KRAS mutant and wildtype). Our study finds that Carbamazepine affects SMARCA4 levels and that this effect is different depending on the KRAS mutation status. This study analyzes the effect of carbamazepine on early-stage autophagy via ULK1 as well as simulates the docking of carbamazepine on KRAS, depending on the mutation status. Our study highlights the therapeutic uses of carbamazepine on cancer, and we propose that carbamazepine in conjunction with other chemotherapies may prove useful in targeting KRAS-mutated colorectal cancer.