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Genentech, Tessaro, and Xcovery; and reports receiving commercial research support from Boehringer Ingelheim. Dr. Whisenant has received personal fees from Anasys Instruments. Dr. Wakelee is a consultant/advisory board member for AstraZeneca, Genentech/ Roche (uncompensated), Merck (uncompensated), Novartis (uncompensated), and Ariad (uncompensated); and has received grants to her institution for conduct of clinical trial work from

The utility of single-chain Fv proteins as therapeutic agents would be realized if the circulating lives of these minimal antigen-binding polypeptides could be both prolonged and adjustable. We have developed a general strategy for creating tailored monoPEGylated single-chain antibodies. Free cysteine residues were engineered in an anti-TNF-alpha scFv at the C-terminus or within the linker segments of both scFv orientations, V(L)-linker-V(H) and V(H)-linker-V(L). High-level expression of 10 designed variant scFv proteins in Pichia pastoris allowed rapid purification. Optimization of site-specific conjugate preparation with 5, 20 and 40 kDa maleimide-PEG polymers was achieved and a comparison of the structural and functional properties of the scFv proteins and their PEGylated counterparts was performed. Peptide mapping and MALDI-TOF mass spectrometric analysis confirmed the unique attachment site for each PEG polymer. Independent biochemical and bioactivity analyses, including binding affinities and kinetics, antigenicity, flow cytometric profiling and cell cytotoxicity rescue, demonstrated that the functional activities of the 10 designed scFv conjugates are maintained, while scFv activity variations between these alternative assays can be correlated with conjugate and analytical designs. Pharmacokinetic studies of the PEGylated scFv in mice demonstrated up to 100-fold prolongation of circulating lives, in a range comparable to clinical antibodies.

Background: Liquid biopsy for plasma circulating tumor DNA (ctDNA) next-generation sequencing (NGS) is commercially available and increasingly adopted in clinical practice despite a paucity of prospective data to support its use. Methods: Patients with advanced lung cancers who had no known oncogenic driver or developed resistance to current targeted therapy (n ¼ 210) underwent plasma NGS, targeting 21 genes. A subset of patients had concurrent tissue NGS testing using a 468-gene panel (n ¼ 106). Oncogenic driver detection, test turnaround time (TAT), concordance, and treatment response guided by plasma NGS were measured. All statistical tests were two-sided. Results: Somatic mutations were detected in 64.3% (135/210) of patients. ctDNA detection was lower in patients who were on systemic therapy at the time of plasma collection compared with those who were not (30/70, 42.9% vs 105/140, 75.0%; OR ¼ 0.26, 95% CI ¼ 0.1 to 0.5, P < .001). The median TAT of plasma NGS was shorter than tissue NGS (9 vs 20 days; P < .001). Overall concordance, defined as the proportion of patients for whom at least one identical genomic alteration was identified in both tissue and plasma, was 56.6% (60/106, 95% CI ¼ 46.6% to 66.2%). Among patients who tested plasma NGS positive, 89.6% (60/ 67; 95% CI ¼ 79.7% to 95.7%) were also concordant on tissue NGS and 60.6% (60/99; 95% CI ¼ 50.3% to 70.3%) vice versa. Patients who tested plasma NGS positive for oncogenic drivers had tissue NGS concordance of 96.1% (49/51, 95% CI ¼ 86.5% to 99.5%), and directly led to matched targeted therapy in 21.9% (46/210) with clinical response. Conclusions: Plasma ctDNA NGS detected a variety of oncogenic drivers with a shorter TAT compared with tissue NGS and matched patients to targeted therapy with clinical response. Positive findings on plasma NGS were highly concordant with tissue NGS and can guide immediate therapy; however, a negative finding in plasma requires further testing. Our findings support the potential incorporation of plasma NGS into practice guidelines.