A phase 3 trial evaluating panitumumab plus best supportive care vs best supportive care in chemorefractory wild-type KRAS or RAS metastatic colorectal cancer.

BACKGROUND: We assessed the treatment effect of panitumumab plus best supportive care (BSC) vs BSC on overall survival (OS) in patients with chemorefractory wild-type KRAS exon 2 metastatic colorectal cancer (mCRC) and report the first prospective extended RAS analysis in a phase 3 trial. METHODS: Patients with wild-type KRAS exon 2 mCRC were randomised 1 : 1 to panitumumab (6 mg kg-1 Q2W) plus BSC or BSC. On-study crossover was prohibited. RAS mutation status was determined by central laboratory testing. The primary endpoint was OS in wild-type KRAS exon 2 mCRC; OS in wild-type RAS mCRC (KRAS and NRAS exons 2, 3, and 4) was a secondary endpoint. RESULTS: Three hundred seventy seven patients with wild-type KRAS exon 2 mCRC were randomised. Median OS was 10.0 months with panitumumab plus BSC vs 7.4 months with BSC (HR=0.73; 95% CI=0.57-0.93; P=0.0096). RAS ascertainment was 86%. In wild-type RAS mCRC, median OS for panitumumab plus BSC was 10.0 vs 6.9 months for BSC (HR=0.70; 95% CI=0.53-0.93; P=0.0135). Patients with RAS mutations did not benefit from panitumumab (OS HR=0.99; 95% CI=0.49-2.00). No new safety signals were observed. CONCLUSIONS: Panitumumab significantly improved OS in wild-type KRAS exon 2 mCRC. The effect was more pronounced in wild-type RAS mCRC, validating previous retrospective analyses.

Biomarker analyses in REGARD gastric/GEJ carcinoma patients treated with VEGFR2-targeted antibody ramucirumab.

BACKGROUND: Angiogenesis inhibition is an important strategy for cancer treatment. Ramucirumab, a human IgG1 monoclonal antibody that targets VEGF receptor 2 (VEGFR2), inhibits VEGF-A, -C, -D binding and endothelial cell proliferation. To attempt to identify prognostic and predictive biomarkers, retrospective analyses were used to assess tumour (HER2, VEGFR2) and serum (VEGF-C and -D, and soluble (s) VEGFR1 and 3) biomarkers in phase 3 REGARD patients with metastatic gastric/gastroesophageal junction carcinoma. METHODS: A total of 152 out of 355 (43%) patients randomised to ramucirumab or placebo had ⩾1 evaluable biomarker result using VEGFR2 immunohistochemistry or HER2, immunohistochemistry or FISH, of blinded baseline tumour tissue samples. Serum samples (32 patients, 9%) were assayed for VEGF-C and -D, and sVEGFR1 and 3. RESULTS: None of the biomarkers tested were associated with ramucirumab efficacy at a level of statistical significance. High VEGFR2 endothelial expression was associated with a non-significant prognostic trend toward shorter progression-free survival (high vs low HR=1.65, 95% CI=0.84,3.23). Treatment with ramucirumab was associated with a trend toward improved survival in both high (HR=0.69, 95% CI=0.38, 1.22) and low (HR=0.73, 95% CI=0.42, 1.26) VEGFR2 subgroups. The benefit associated with ramucirumab did not appear to differ by tumoural HER2 expression. CONCLUSIONS: REGARD exploratory analyses did not identify a strong potentially predictive biomarker of ramucirumab efficacy; however, statistical power was limited.

Molecular basis and therapeutic targets in prostate cancer: A comprehensive review.

Prostate cancer is one of the most significant causes of morbidity and mortality in male patients. The incidence increases with age, and it is higher among African Americans. The occurrence of prostate cancer is associated with many risk factors, including genetic and hereditary predisposition. The most common genetic syndromes associated with prostate cancer risk are BRCA-associated hereditary breast and ovarian cancer (HBOC) and Lynch syndrome. Local-regional therapy, i.e., surgery is beneficial in early-stage prostate cancer management. Advanced and metastatic prostate cancers require systemic therapies, including hormonal inhibition, chemotherapy, and targeted agents. Most prostate cancers can be treated by targeting the androgen-receptor pathway and decreasing androgen production or binding to androgen receptors (AR). Castration-resistant prostate cancer (CRPC) usually involves the PI3K/AKT/mTOR pathway and requires targeted therapy. Specific molecular therapy can target mutated cell lines in which DNA defect repair is altered, caused by mutations of BRCA2, partner and localizer of BRCA2 (PALB2), and phosphatase and tensin homolog (PTEN) or the transmembrane protease serine 2-ERG (TMPRSS2-ERG) fusion. Most benefits were demonstrated in cyclin dependent-kinase 12 (CDK12) mutated cell lines when treated with anti-programmed cell death protein 1 (PD1) therapy. Therapies targeting p53 and AKT are the subject of ongoing clinical trials. Many genetic defects are listed as diagnostic, prognostic, and clinically actionable markers in prostate cancer. Androgen receptor splice variant 7 (AR-V7) is an important oncogenic driver and an early diagnostic and prognostic marker, as well as a therapeutic target in hormone-resistant CRPC. This review summarizes the pathophysiological mechanisms and available targeted therapies for prostate cancer.

Evaluating Alternative Ramucirumab Doses as a Single Agent or with Paclitaxel in Second-Line Treatment of Locally Advanced or Metastatic Gastric/Gastroesophageal Junction Adenocarcinoma: Results from Two Randomized, Open-Label, Phase II Studies.

Studies JVDB and JVCZ examined alternative ramucirumab dosing regimens as monotherapy or combined with paclitaxel, respectively, in patients with advanced/metastatic gastric/gastroesophageal junction (GEJ) adenocarcinoma. For JVDB, randomized patients (N = 164) received ramucirumab monotherapy at four doses: 8 mg/kg every 2 weeks (Q2W) (registered dose), 12 mg/kg Q2W, 6 mg/kg weekly (QW), or 8 mg/kg on days 1 and 8 (D1D8) every 3 weeks (Q3W). The primary objectives were the safety and pharmacokinetics of ramucirumab monotherapy. For JVCZ, randomized patients (N = 245) received paclitaxel (80 mg/m2-D1D8D15) plus ramucirumab (8 mg/kg- or 12 mg/kg-Q2W). The primary objective was progression-free survival (PFS) of 12 mg/kg-Q2W arm versus placebo from RAINBOW using meta-analysis. Relative to the registered dose, exploratory dosing regimens (EDRs) led to higher ramucirumab serum concentrations in both studies. EDR safety profiles were consistent with previous studies. In JVDB, serious adverse events occurred more frequently in the 8 mg/kg-D1D8-Q3W arm versus the registered dose; 6 mg/kg-QW EDR had a higher incidence of bleeding/hemorrhage. In JVCZ, PFS was improved with the 12 mg/kg plus paclitaxel combination versus placebo in RAINBOW; however, no significant PFS improvement was observed between the 12 mg/kg and 8 mg/kg arms. The lack of a dose/exposure-response relationship in these studies supports the standard dose of ramucirumab 8 mg/kg-Q2W as monotherapy or in combination with paclitaxel as second-line treatment for advanced/metastatic gastric/GEJ adenocarcinoma.

Final Analysis of Outcomes and RAS/BRAF Status in a Randomized Phase 3 Study of Panitumumab and Best Supportive Care in Chemorefractory Wild Type KRAS Metastatic Colorectal Cancer.

INTRODUCTION: Tumor rat sarcoma gene (RAS) status is a negative predictive biomarker for anti-epidermal growth factor receptor (EGFR) therapy in metastatic colorectal cancer (mCRC). We analyzed outcomes according to RAS and v-Raf murine sarcoma viral oncogene homolog B (BRAF) mutational status, and evaluated early tumor shrinkage (ETS) and depth of response (DpR) for patients with wild type RAS. PATIENTS AND METHODS: Patients with confirmed metastatic colon or rectum adenocarcinoma, wild type Kristen rat sarcoma gene tumor exon 2 status, clinical/radiologic disease progression or toxicity during irinotecan or oxaliplatin treatment, and no previous anti-EGFR therapy were randomized 1:1 to receive best supportive care (BSC) with or without panitumumab (6.0 mg/kg, intravenously, on day 1 of each 14-day cycle) in this open-label, multicenter, phase III study (20100007). RAS and BRAF mutation status were determined using Sanger sequencing. ETS was evaluated as maximum percentage change from baseline to week 8; DpR was calculated as the percentage change for tumor shrinkage at nadir versus baseline. RESULTS: Overall, 270 patients had RAS wild type mCRC (panitumumab with BSC, n = 142; BSC, n = 128). For patients with wild type RAS tumors, median overall survival (OS; hazard ratio [HR], 0.72; P = .015) and progression-free survival (PFS; HR, 0.45; P < .0001) were improved with panitumumab with BSC versus BSC. Similar improvements were seen for patients with wild type RAS, and wild type BRAF tumors (OS: HR, 0.75; P = .04; PFS: HR, 0.45; P < .0001). Median DpR was 16.9% for the evaluable panitumumab with BSC wild type RAS population. Overall, 69.5% experienced any type of tumor shrinkage at week 8; 38.2% experienced ≥ 20% shrinkage. Similar improvements in OS and PFS were seen with stratification according to ETS. CONCLUSION: This analysis showed that panitumumab improved outcomes in wild type RAS mCRC and indicated that ETS and DpR could be used as additional efficacy markers.