Paul D. Swanson

Lack of Correlation between Epidermal Growth Factor Receptor Status and Response to Panitumumab Monotherapy in Metastatic Colorectal Cancer

Purpose: Panitumumab, a fully human anti–epidermal growth factor receptor (EGFR) monoclonal antibody, is approved as monotherapy for the treatment of metastatic colorectal cancer. We evaluated the association of tumor EGFR expression levels with outcomes in patients with chemorefractory metastatic colorectal cancer. Experimental Design: Two phase II, multicenter, single-arm, open-label studies enrolled chemorefractory patients with tumors expressing low/negative (1-9%/<1%; Low/Negative EGFR study) or high (≥10%; High EGFR study) levels of EGFR. Patients received panitumumab 6 mg/kg every two weeks until disease progression or intolerance. End points included objective response rate (per response evaluation criteria in solid tumors), progression-free survival (PFS), overall survival (OS), and safety. Exploratory analyses by tumor KRAS status were carried out. Results: A total of 203 patients (Low/Negative EGFR) and 185 patients (High EGFR) enrolled in the studies. The overall response rate was 5.7% [95% confidence interval (95% CI), 2.6-10.5] in patients with low/negative EGFR and 4.2% (95% CI, 1.6-9.0) in patients with high EGFR; the response rate at week 16 was 4% in both studies (all partial responses). Median PFS times were 8.1 weeks (95% CI, 7.1-12.6), 8.1 weeks (95% CI, 7.4-11.1), and 7.3 weeks (95% CI, 7.1-7.6) in patients with negative, low, and high levels of EGFR expression, respectively. PFS and OS were longer in patients with wild-type KRAS than those with mutant KRAS. As expected, most adverse events were skin related. Conclusions: These studies confirm previous reports that tumor EGFR expression levels are not associated with efficacy with an anti-EGFR antibody and that anti-EGFR antibody therapy should be limited to those patients whose tumors express wild-type KRAS. Clin Cancer Res; 16(7); 2205–13. ©2010 AACR.

Electron-cyclotron resonance etching of mirrors for ridge-guided lasers

Etched laser mirrors are important for the monolithic integration of lasers in optical circuits without cleaved facets. Electron cyclotron resonance (ECR) etching is ideal for opto-electronic fabrication since the etching parameters are independently adjustable and a variety of masking materials are available for creating multiple etch depths, e.g., for etched ridge lasers with etched mirror facets. We report on the fabrication and characterization of ECR etched laser mirrors and waveguides. The quality of the ECR etch is ascertained by measuring the reflection coefficients of 90/spl deg/ turning mirrors in GaAs-AlGaAs multiple-quantum-well (MQW) lasers incorporating multiple numbers of 90/spl deg/ bends. The average reflection coefficient is found to be approximately 80%.<<ETX>>

Square broad-area multiple-quantum-well laser

A new single-element broad-area laser has been designed, fabricated, and tested for use as an integrated optical memory element or logic gate. The design incorporates a square gain section and an intracavity saturable absorber for each of the two orthogonal cavities. The devices lases in two spatially orthogonal modes that can be independently modulated by the two saturable absorbers.

Diode laser logic for use as smart pixels for optical signal processing

Diode Laser Logic is a complete, new logic family comprised of Q- switched lasers and photodetectors. The lasers and detectors are monolithically integrated on multiple quantum well laser heterostructure with semi-insulating substrates. Preliminary results indicate an ON/OFF contrast ratio better than 500:1 and a gain in excess of 20. As a result, the devices can be cascaded to form more complex optical circuits. In addition to introducing the Diode Laser Logic family, a basic model is presented and the fabrication process is discussed.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.