Allen Lee Cohn

Purpose To characterize ramucirumab exposure–response relationships for efficacy and safety in patients with metastatic colorectal cancer (mCRC) using data from the RAISE study. Methods Sparse pharmacokinetic samples were collected; a population pharmacokinetic analysis was conducted. Univariate and multivariate Cox proportional hazards models analyzed the relationship between predicted ramucirumab minimum trough concentration at steady state (C _min,ss) and survival. Kaplan–Meier analysis was used to evaluate survival from patients in the ramucirumab plus folinic acid, 5-fluorouracil, and irinotecan (FOLFIRI) treatment arm stratified by C _min,ss quartiles (Q). An ordered categorical model analyzed the relationship between C _min,ss and safety outcomes. Results Pharmacokinetic samples from 906 patients were included in exposure–efficacy analyses; samples from 905 patients were included in exposure–safety analyses. A significant association was identified between C _min,ss and overall survival (OS) and progression-free survival (PFS) (p < 0.0001 for both). This association remained significant after adjusting for baseline factors associated with OS or PFS (p < 0.0001 for both). Median OS was 11.5, 12.9, 16.4, and 16.7, and 12.4 months for ramucirumab C _min,ss Q1, Q2, Q3, Q4, and placebo group, respectively. Median PFS was 5.4, 4.6, 6.8, 8.5, and 5.2 months for ramucirumab C _min,ss Q1, Q2, Q3, Q4, and placebo group, respectively. The risk of Grade ≥3 neutropenia was associated with an increase in ramucirumab exposure. Conclusions Exploratory exposure–response analyses suggested a positive relationship between efficacy and ramucirumab exposure with manageable toxicities in patients from the RAISE study with mCRC over the ranges of exposures achieved by a dose of 8 mg/kg every 2 weeks in combination with FOLFIRI.

Background: Mutations in the BRAF gene have been implicated in several human cancers. The objective of this screening study was to identify patients with solid tumors (other than metastatic melanoma or papillary thyroid cancer) or multiple myeloma harboring activating BRAF^V600 mutations for enrollment in a vemurafenib clinical study. Methods: Formalin-fixed, paraffin-embedded tumor samples were collected and sent to a central laboratory to identify activating BRAF^V600 mutations by bidirectional direct Sanger sequencing. Results: Overall incidence of BRAF^V600E mutation in evaluable patients (n=548) was 3% (95% confidence interval [CI], 1.7–4.7): 11% in colorectal tumors (n=75), 6% in biliary tract tumors (n=16), 3% in non-small cell lung cancers (n=71), 2% in other types of solid tumors (n=180), and 3% in multiple myeloma (n=31). There were no BRAF^V600 mutations in this cohort of patients with ovarian tumors (n=68), breast cancer (n=86), or prostate cancer (n=21). Conclusion: This multicenter, national screening study confirms previously reported incidences of BRAF^V600 mutations from single-center studies. Patients identified with BRAF^V600 mutations were potentially eligible for enrollment in the VE-BASKET study.

Targeted agents presently available for mutant KRAS metastatic colorectal cancer (mCRC) are bevacizumab and aflibercept. We evaluated the efficacy and safety of conatumumab (an agonistic monoclonal antibody against human death receptor 5) and ganitumab (a monoclonal antibody against the type 1 insulin-like growth factor receptor) combined with standard FOLFIRI chemotherapy as a second-line treatment in patients with mutant KRAS mCRC. Patients with mutant KRAS metastatic adenocarcinoma of the colon or rectum refractory to fluoropyrimidine- and oxaliplatin-based chemotherapy were randomized 1 : 1 : 1 to receive intravenous FOLFIRI plus conatumumab 10 mg/kg (Arm A), ganitumab 12 mg/kg (Arm B), or placebo (Arm C) Q2W. The primary end point was progression-free survival (PFS). In total, 155 patients were randomized. Median PFS in Arms A, B, and C was 6.5 months (HR, 0.69; P = 0.147), 4.5 months (HR, 1.01; P = 0.998), and 4.6 months, respectively; median overall survival was 12.3 months (HR, 0.89; P = 0.650), 12.4 months (HR, 1.27; P = 0.357), and 12.0 months; and objective response rate was 14%, 8%, and 2%. The most common grade ≥3 adverse events in Arms A/B/C included neutropenia (30%/25%/18%) and diarrhea (18%/2%/10%). Conatumumab, but not ganitumab, plus FOLFIRI was associated with a trend toward improved PFS. Both combinations had acceptable toxicity.

Pemetrexed has demonstrated activity in hepatocellular carcinoma (HCC) cell lines, and has a manageable toxicity profile in clinical trials, suggesting its potential as a treatment for HCC patients. A multicenter, Phase II community-based study was conducted to assess the response rate and toxicity profile of single-agent pemetrexed in first-line patients with advanced or metastatic HCC. Patients premedicated with folic acid, vitamin B₁₂, and dexamethasone were administered pemetrexed 600 mg/m² IV on day 1 of each 21-day cycle until disease progression. This nonrandomized study employed Simon’s 2-stage design, enrolling 21 eligible patients in the first stage, stopping accrual if ≤2 responders were observed. Responses were four stable disease, 14 progressive disease, and three not evaluable: two had early toxicities (renal/liver failure, sepsis) and one was noncompliant. The most common grade 3 hematological toxicities were neutropenia 6 of 21 (29%) and thrombocytopenia 3 of 21 (14%); with no grade 4 toxicities. Thirteen patients died on-study: 12 PD and one liver failure; none were drug-related. The median survival was 5.2 months (range, <1–12.2). The planned second stage was cancelled, and the trial was closed owing to lack of response. While pemetrexed was tolerated in this patient population, it was not active.