EGFR testing patterns and detection of EGFR exon 20 insertions among patients with NSCLC in the US

Introduction/Objective

Epidermal growth factor receptor (EGFR) mutations are common in non-small cell lung cancer (NSCLC). EGFR exon 20 insertions (EGFRex20ins), a rare subset of EGFR mutations, are refractory to tyrosine kinase inhibitors. With the development of targeted therapies for EGFRex20ins, such as mobocertinib, molecular testing is required to optimize treatment. A better understanding of real-world EGFR detection patterns is needed to maximize patient outcomes.

Methods/Case Report

This retrospective study describes EGFR testing and EGFRex20ins detection patterns in patients with NSCLC in the United States. The Flatiron Health electronic health record database was used to identify patients ≥18 years, with advanced NSCLC, and with ≥2 clinic visits between 01/01/2011 and 12/31/2020. Baseline demographics, clinical characteristics, EGFR testing, and EGFRex20ins detection rates by sex, race, and smoking history were summarized.

Results (if a Case Study enter NA)

A total of 67,281 patients with NSCLC were identified. EGFR testing increased from 44% in 2011 to 77% in 2020. Of all patients, 44,926 (66.8%) were tested: 50.8% female; 3.3% Asian; 16.0% never-smokers. Of all patients, 22,355 (33.2%) were not tested: 41.4% female; 1.2% Asian; 7.5% never-smokers. Of those tested, 6,245 (13.9%) patients had EGFR mutations: 65.9% female; 11.8% Asian; 48.4% never-smokers.

EGFRex20ins detection rates changed from 0.6% in 2011 to 1.0% in 2019 and 0.7% in 2020. Of those tested, 304 patients had EGFRex20ins: 58.2% female; 8.2% Asian; 50.3% never-smokers. EGFR testing was higher in females (71.2%) than males (62.8%), never-smokers (84.5%) than those with a smoking history (64.6%), and Asian patients (84.2%) than White (66.6%), Black (65.4%), or other patients (69.5%). Of those tested, EGFRex20ins mutations were detected in 0.8% of females (males: 0.6%), 2.2% of never-smokers (with smoking history: 0.4%), and 1.7% of Asians (White: 0.6%, Black: 0.6%, other patients: 0.7%) had EGFRex20ins. A similar trend was observed for EGFR mutations with higher proportions of females, never-smokers, and Asian patients affected.

Conclusion

EGFR testing and EGFRex20ins detection rates have increased. However, not all patient subgroups were tested at the same rate and undertesting occurred in all subgroups. Further education of specialists diagnosing NSCLC is warranted to ensure all patients receive biomarker testing and benefit from emerging EGFRex20ins- targeted therapies.

Decreased antibiotic exposure using a procalcitonin protocol for respiratory infections and sepsis in US community hospitals (ProCommunity)

OBJECTIVE

Antibiotic overuse leading to antimicrobial resistance is a global public health concern. Clinical trials have demonstrated that procalcitonin-based decision-making for antibiotic therapy can safely decrease inappropriate antibiotic use in patients with respiratory infections and sepsis, but real-world data are scarce. This study sought to assess the impact of a procalcitonin-based antibiotic stewardship program (protocol plus education) on antibiotic use in community hospitals.

METHODS

An observational, retrospective, matched cohort study was conducted. Eligible patients treated in hospitals with a procalcitonin-based protocol plus education (Procalcitonin cohort hospitals) were matched to patients admitted to facilities without procalcitonin testing (Control cohort hospitals) using a 1:2 ratio. The Control hospitals were facilities where procalcitonin testing was not available on site. Patient matching was based on: (1) age, (2) gender, (3) admission diagnosis code using groupings of the International Classification of Diseases, 10th Revision, (4) whether patients were admitted to the intensive care unit, and (5) whether a blood culture test was performed. Procalcitonin cohort hospitals implemented a quality improvement initiative, where procalcitonin was available, used regularly, and clinicians (physicians and pharmacists) were educated on its use.

RESULTS

After adjustment, patients in the Procalcitonin cohort had 1.47 fewer antibiotic days (9.1 vs. 8.5 days, 95%CI: -2.72; -0.22, p = .021). There was no difference in length of stay or adverse clinical outcomes except for increase in acute kidney injury (odds ratio = 1.26, 95%CI: 1.01; 1.58, p = .038).

CONCLUSIONS

Patients with respiratory infections and sepsis in hospitals utilizing a procalcitonin-based protocol coupled with education received fewer days of antibiotic therapy.

Construction, characterization, and immunization of nanoparticles that display a diverse array of influenza HA trimers

Current influenza vaccines do not elicit broadly protective immune responses against multiple strains. New strategies to focus the humoral immune response to conserved regions on influenza antigens are therefore required for recognition by broadly neutralizing antibodies. It has been suggested that B-cells with receptors that recognize conserved epitopes would be preferentially stimulated through avidity effects by mosaic particles presenting multiple forms of a variable antigen. We adapted SpyCatcher-based platforms, AP205 virus-like particles (VLPs) and mi3 nanoparticles (NPs), to covalently co-display SpyTagged hemagglutinin (HA) trimers from group 1 and group 2 influenza A strains. Here we show successful homotypic and heterotypic conjugation of up to 8 different HA trimers to both VLPs and NPs. We characterized the HA-VLPs and HA-NPs by cryo-electron tomography to derive the average number of conjugated HAs and their separation distances on particles, and compared immunizations of mosaic and homotypic particles in wild-type mice. Both types of HA particles elicited strong antibody responses, but the mosaic particles did not consistently elicit broader immune responses than mixtures of homotypic particles. We conclude that covalent attachment of HAs from currently-circulating influenza strains represents a viable alternative to current annual influenza vaccine strategies, but in the absence of further modifications, is unlikely to represent a method for making a universal influenza vaccine.

Mosaic nanoparticles elicit cross-reactive immune responses to zoonotic coronaviruses in mice

Protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and SARS-related emergent zoonotic coronaviruses is urgently needed. We made homotypic nanoparticles displaying the receptor binding domain (RBD) of SARS-CoV-2 or co-displaying SARS-CoV-2 RBD along with RBDs from animal betacoronaviruses that represent threats to humans (mosaic nanoparticles with four to eight distinct RBDs). Mice immunized with RBD nanoparticles, but not soluble antigen, elicited cross-reactive binding and neutralization responses. Mosaic RBD nanoparticles elicited antibodies with superior cross-reactive recognition of heterologous RBDs relative to sera from immunizations with homotypic SARS-CoV-2-RBD nanoparticles or COVID-19 convalescent human plasmas. Moreover, after priming, sera from mosaic RBD-immunized mice neutralized heterologous pseudotyped coronaviruses as well as or better than sera from homotypic SARS-CoV-2-RBD nanoparticle immunizations, demonstrating no loss of immunogenicity against particular RBDs resulting from co-display. A single immunization with mosaic RBD nanoparticles provides a potential strategy to simultaneously protect against SARS-CoV-2 and emerging zoonotic coronaviruses.

Mosaic nanoparticles elicit cross-reactive immune responses to zoonotic coronaviruses in mice

Protection against SARS-CoV-2 and SARS-related emergent zoonotic coronaviruses is urgently needed. We made homotypic nanoparticles displaying the receptor-binding domain (RBD) of SARS-CoV-2 or co-displaying SARS-CoV-2 RBD along with RBDs from animal betacoronaviruses that represent threats to humans (mosaic nanoparticles; 4–8 distinct RBDs). Mice immunized with RBD-nanoparticles, but not soluble antigen, elicited cross-reactive binding and neutralization responses. Mosaic-RBD-nanoparticles elicited antibodies with superior cross-reactive recognition of heterologous RBDs compared to sera from immunizations with homotypic SARS-CoV-2–RBD-nanoparticles or COVID-19 convalescent human plasmas. Moreover, sera from mosaic-RBD–immunized mice neutralized heterologous pseudotyped coronaviruses equivalently or better after priming than sera from homotypic SARS-CoV-2–RBD-nanoparticle immunizations, demonstrating no immunogenicity loss against particular RBDs resulting from co-display. A single immunization with mosaic-RBD-nanoparticles provides a potential strategy to simultaneously protect against SARS-CoV-2 and emerging zoonotic coronaviruses.

One sentence summary: Nanoparticle strategy for pan-sarbecovirus vaccine

Immunizing with nanoparticles displaying diverse coronavirus RBDs elicits cross-reactive and neutralizing antibody responses.

Measuring The Impact Of Air Pollution On Health Care Costs

Air pollution contributes to the development of numerous adverse human health outcomes. The Environmental Protection Agency's Environmental Benefits Mapping and Analysis Program-Community Edition (BenMAP-CE) tool is widely used in estimating the health care costs of air pollution and in the development of federal and state regulations and policy. Its default features consider only the costs of hospital and emergency department admissions. A more complete accounting of the chain of costs would include ambulatory and other care. In this article we use employer health insurance claims data to infer additional costs that accompany hospitalizations but are not included in BenMAP-CE. Including additional categories increases BenMAP-CE health care cost estimates by approximately 40 percent for respiratory and cardiovascular patients. That is, for each dollar of health care costs captured by BenMAP-CE, a more complete accounting would include an additional 40 cents. These results suggest that because such air pollution costs are underestimated, the health care benefits associated with reducing air pollution may be much larger than previously estimated.

ProCommunity: procalcitonin use in real-world US community hospital settings

OBJECTIVE

Procalcitonin (PCT) is a biomarker that may help providers optimize antibiotic (AB) therapy. Numerous clinical trials have demonstrated the utility of PCT-guided decision algorithms in treating lower respiratory tract infections and sepsis, but evidence from real-world studies is limited. This study sought to evaluate the effects of PCT on select clinical outcomes in community hospitals.

METHODS

An observational, retrospective, case-control study was conducted. Hospitals from a large US hospital system were categorized into "treatment" and "control" hospitals. Treatment hospitals were those with in-house PCT testing, a pharmacy team tasked with PCT testing follow-up and results in the patient's electronic medical records alongside a recommendation on AB treatment. Control hospitals either did not have PCT testing available in house or sent out tests to a laboratory or neighboring facility. Patients from treatment hospitals were matched 1:1 to patients from control hospitals based on admission diagnosis code, sex, age and whether an intensive care unit admission was observed. Clinical outcomes included number of days of AB treatment, length of stay, 30 day readmissions, mortality and acute kidney injury. Comparisons were conducted using multivariable regressions accounting for clustering at the hospital level.

RESULTS

Patients from treatment hospitals had significantly shorter hospital stays (-0.68 days, 95% CI: -1.26, -0.09; p = .02). A reduction in days of AB treatment (-1.50 days, 95% CI: -3.27, 0.27; p = .10) was observed, but did not reach statistical significance.

CONCLUSION

These findings suggest that PCT, along with specific treatment recommendations, may lead to shortened hospital stays with no adverse outcome on patient safety.

MACC1 silencing inhibits cell proliferation and induces cell apoptosis of lung adenocarcinoma cells through the β-catenin pathway

It has been documented that over-expression of metastasis-associated in colon cancer-1 (MACC1) is related to poor prognosis in non-small cell lung cancer (NSCLC). This study investigates the function and underlying molecular mechanisms of MACC1 in lung adenocarcinoma. Here, we firstly employed immunohistochemistry, western blotting, real-time PCR, and online database to demonstrate that MACC1 expression was elevated in tumor tissues compared with tumoradjacent or normal tissues. Real-time PCR, CCK-8, colony formation western blotting, Hoechst staining, and flow cytometry assays then evaluated the effects of MACC1 knockdown on the cell cycle, cell proliferation and apoptosis in A549  and H1299 adenocarcinoma cells. Result highlighted that MACC1 knockdown inhibited cell proliferation, induced G0/ G1 phase arrest and promoted cell apoptosis in vitro. Mechanistic analysis revealed it also up-regulated expression levels of bax, cleaved-caspase-3 and cleaved-PARP while down-regulating cyclin D1, c-myc, bcl-2, and β-catenin expression in A549 cells. Intriguingly, up-regulation of β-catenin suppressed G0/G1 phase arrest and apoptosis in MACC1-silenced A549 cells and this was accompanied by increased levels of cyclin D1, c-myc, and bcl-2. Collectively, our results indicate that MACC1 knockdown effectively inhibited cell proliferation and promoted apoptosis of lung adenocarcinoma cells by regulating the β-catenin pathway.

Are some neighborhoods bad for your waistline? A test of neighborhood exposure effects on BMI

I study the causal impact of neighborhoods on body mass index (BMI). Through exploiting variation in the number of years individuals have lived in their neighborhood, using a data set from California, I examine if there exist causal effects of exposure to neighborhoods with high potential effects on one's BMI. The identifying assumption is that there are no unobserved individual level characteristics correlated with both BMI and moving, after controlling for observables. I find evidence that suggests that neighborhoods do not have a causal impact on BMI.

Low Wall Shear Stress Is Associated with Local Aneurysm Wall Enhancement on High-Resolution MR Vessel Wall Imaging

BACKGROUND AND PURPOSE

Some retrospective studies have found that the aneurysm wall enhancement on high-resolution MR vessel wall postgadolinium T1WI has the potential to distinguish unstable aneurysms. This study aimed to identify hemodynamic characteristics that differ between the enhanced and nonenhanced areas of the aneurysm wall on high-resolution MR vessel wall postgadolinium T1WI.

MATERIALS AND METHODS

TOF-MRA and high-resolution MR vessel wall T1WI of 25 patients were fused to localize the enhanced area of the aneurysm wall. Using computational fluid dynamics, we studied the aneurysm models. Mean static pressure, mean wall shear stress, and oscillatory shear index were compared between the enhanced and nonenhanced areas.

RESULTS

The aneurysmal enhanced area had lower wall shear stress (P < .05) and a lower oscillatory shear index (P = .021) than the nonenhanced area. In addition, the whole aneurysm had lower wall shear stress (P < .05) and a higher oscillatory shear index (P = .007) than the parent artery.

CONCLUSIONS

This study suggests that there are hemodynamic differences between the enhanced and nonenhanced areas of the aneurysm wall on high-resolution MR vessel wall postgadolinium T1WI.

Fully automated high-throughput chromatin immunoprecipitation for ChIP-seq: identifying ChIP-quality p300 monoclonal antibodies

Chromatin immunoprecipitation coupled with DNA sequencing (ChIP-seq) is the major contemporary method for mapping in vivo protein-DNA interactions in the genome. It identifies sites of transcription factor, cofactor and RNA polymerase occupancy, as well as the distribution of histone marks. Consortia such as the ENCyclopedia Of DNA Elements (ENCODE) have produced large datasets using manual protocols. However, future measurements of hundreds of additional factors in many cell types and physiological states call for higher throughput and consistency afforded by automation. Such automation advances, when provided by multiuser facilities, could also improve the quality and efficiency of individual small-scale projects. The immunoprecipitation process has become rate-limiting, and is a source of substantial variability when performed manually. Here we report a fully automated robotic ChIP (R-ChIP) pipeline that allows up to 96 reactions. A second bottleneck is the dearth of renewable ChIP-validated immune reagents, which do not yet exist for most mammalian transcription factors. We used R-ChIP to screen new mouse monoclonal antibodies raised against p300, a histone acetylase, well-known as a marker of active enhancers, for which ChIP-competent monoclonal reagents have been lacking. We identified, validated for ChIP-seq, and made publicly available a monoclonal reagent called ENCITp300-1.

Bioinformatics analysis of gene expression profiles in the rat cerebral cortex following traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a serious neurodisorder commonly caused by sports related events or violence. It is the leading cause of disability in people under 40.

AIM

In order to elucidate the molecular mechanism of the secondary injury after TBI.

MATERIALS AND METHODS

In this study, we downloaded gene expression profile on TBI model with sham controls for gene set enrichment analysis and pathway analysis.

RESULTS

At a q-value of 5%, 361 genes were up-regulated and 373 were down-regulated in samples obtained at 48 hours after TBI. Functional analyses revealed that steroid biosynthesis, cell cycle, metal ion transport, inflammation and apoptosis were significantly dysregulated during the late period after trauma. In addition, MAPK3 (mitogen-activated protein kinase 3), was identified as the hub node in the protein-protein interaction (PPI) network constructed by the differentially expressed genes (DEGs).

CONCLUSIONS

Further elucidation of genes and proteins in our study may reveal their potential as novel therapeutic targets.

Antibodies and intrabodies against huntingtin: production and screening of monoclonals and single-chain recombinant forms

Antibodies can be extremely useful tools for the field of triplet repeats diseases. These reagents are important for localizing proteins in tissues and they can be used in the isolation and characterization of the components of protein complexes. In the context of huntingtin (Htt), antibodies can distinguish Htt with normal or an expanded polyglutamine (polyQ) repeats, and they can identify distinct conformations of Htt. Htt is the protein that, when mutated to contain an expanded polyQ motif, causes Huntington's disease (HD). Our group has produced monoclonal and recombinant single-chain antibodies (intrabodies) that can be used for these purposes and to perturb the function of Htt in living cells. Studies with anti-Htt intrabodies have led to identification of novel pathogenic epitopes. Moreover, some of the isolated intrabodies can reduce the neurotoxicity of mutant Htt in cell culture and animal models of HD. Thus, the production of antibodies and intrabodies has made a significant contribution to the understanding of HD pathogenesis and has introduced a novel strategy to treat this debilitating neurodegenerative disorder.

Structures of Abeta-related peptide--monoclonal antibody complexes

Passive immunotherapy (PI) is being explored as a potential therapeutic against Alzheimer's disease. The most promising antibodies (Abs) used in PI target the EFRH motif of the Abeta N-terminus. The monoclonal anti-Abeta Ab PFA1 recognizes the EFRH epitope of Abeta. PFA1 has a high affinity for Abeta fibrils and protofibrils (0.1 nM), as well as good affinity for Abeta monomers (20 nM). However, PFA1 binds the toxic N-terminally modified pyroglutamate peptide pyro-Glu3-Abeta with a 77-fold loss in affinity compared to the WT Abeta(1-8). Furthermore, our earlier work illustrated PFA1's potential for cross-reactivity. The receptor tyrosine kinase Ror2, which plays a role in skeletal and bone formation, possesses the EFRH sequence. PFA1 Fab binds the Ror2(518-525) peptide sequence REEFRHEA with a 3-fold enhancement over WT Abeta(1-8). In this work, the crystal structures of the hybridoma-derived PFA1 Fab in complex with pyro-Glu3-Abeta peptide and with a cross-reacting peptide from Ror2 have been determined at resolutions of 1.95 and 2.7 A, respectively. As with wild-type Abeta, these peptides bind to the Fab via a combination of charge- and shape-complementarity, hydrogen-bonding, and hydrophobic interactions. Comparison of the structures of the four peptides Abeta(1-8), Grip1, pyro-Glu3-Abeta(3-8), and Ror2 in complex with PFA1 shows that the greatest conformational flexibility occurs at residues 2 to 3 and 8 of the peptide. These structures provide a molecular basis of the specificity tolerance of PFA1 and its ability to recognize Abeta N-terminal heterogeneity. The structures provide clues to improving mAb specificity and affinity for pyroglutamate Abeta.

Clinical activity observed in a phase I dose escalation trial of an oral c-met and ALK inhibitor, PF-02341066

3509

Background: PF-02341066 (PF) is a selective, ATP-competitive, small molecule oral inhibitor of the c-Met/HGFR and ALK receptor tyrosine kinases that has not previously been tested in humans. A Phase 1 dose-escalation trial evaluating PF as an oral single agent was conducted to investigate safety, PK and PD in patients (pts) with advanced cancer (excluding leukemias). Methods: PF was administered under fasting conditions QD or BID on a continuous schedule to pts in successive dose-escalating cohorts at doses ranging from 50 mg QD to 300 mg BID. Pts with advanced cancer were enrolled in the study. Results: Thirty-seven pts were enrolled into the dose escalation part of the study. Tumor types included colorectal, pancreatic, sarcoma, ALCL and NSCLC. The MTD was 250 mg BID. Three DLTs were observed: grade 3 increase in ALT (1 pt at 200 mg QD) and grade 3 fatigue (2 pts at 300 mg BID). The most common AEs were nausea, emesis, fatigue and diarrhea. Nausea and emesis were independent of dose or duration of treatment. Mean AUC (30–57% CV) and Cmax (36–69% CV) increased proportionally with dose from 100 mg QD to 300 mg BID. The median terminal half-life was 46 hours. A 2- to 4-fold increase in the oral midazolam (MDZ) AUC was observed following 28-days of PF dosing at 100 mg QD (n = 3) and 300 mg BID (n = 2), respectively, suggesting PF to be an inhibitor of CYP3A. Ten pts have entered an enriched RP2D cohort of pts with tumors harboring c-Met amplification/gene mutation or ALK fusion genes. There has been 1 confirmed PR in a sarcoma pt with ALK rearrangement (inflammatory myofibroblastic tumor). Among 10 NSCLC pts whose tumors harbor EML4-ALK rearrangement, 1 pt has had a PR, 2 pts have achieved unconfirmed PR and 4 pts have had SD (3 have experienced reduction in tumor burden by ∼20% in measurable lesions and 1 has been treated for 28 weeks). Conclusions: The MTD of PF is 250 mg BID. The major AEs were fatigue or GI-related, and all AEs were manageable and reversible. There was no evidence of non-linear PK at PF doses >100 QD. Treatment with PF-02341066 resulted in promising clinical activity against tumors carrying activating ALK gene rearrangements. Further study of PF in pts with ALK-dependent tumors is warranted.

[Table: see text]

Molecular basis for passive immunotherapy of Alzheimer's disease

Amyloid aggregates of the amyloid-beta (Abeta) peptide are implicated in the pathology of Alzheimer's disease. Anti-Abeta monoclonal antibodies (mAbs) have been shown to reduce amyloid plaques in vitro and in animal studies. Consequently, passive immunization is being considered for treating Alzheimer's, and anti-Abeta mAbs are now in phase II trials. We report the isolation of two mAbs (PFA1 and PFA2) that recognize Abeta monomers, protofibrils, and fibrils and the structures of their antigen binding fragments (Fabs) in complex with the Abeta(1-8) peptide DAEFRHDS. The immunodominant EFRHD sequence forms salt bridges, hydrogen bonds, and hydrophobic contacts, including interactions with a striking WWDDD motif of the antigen binding fragments. We also show that a similar sequence (AKFRHD) derived from the human protein GRIP1 is able to cross-react with both PFA1 and PFA2 and, when cocrystallized with PFA1, binds in an identical conformation to Abeta(1-8). Because such cross-reactivity has implications for potential side effects of immunotherapy, our structures provide a template for designing derivative mAbs that target Abeta with improved specificity and higher affinity.

Proposed staging system modifications for advanced bronchioloalveolar carcinoma supported with a population-based validation study

7559

Background: Concordant with surgical series, our prior analysis of US SEER data demonstrates improved survival for BAC patients with stage IIIB disease due to multiple lesions in the same lobe compared to other stage IIIB patients, and also for patients with ipsilateral multicentric BAC compared to those with distant metastasis. In order for the BAC staging system to accurately reflect survival for these distinct patient subsets, we propose a revised staging system for advanced BAC and validate this system using California Cancer Registry (CCR) data. Methods: A case-only analysis of incident BAC cases in CCR during 1999–2003 was conducted. Based on modeling from our prior SEER analysis, the T4 descriptor for multiple tumors in the same lobe was downstaged to T3, and the M1 descriptor for ipsilateral multicentric BAC was downstaged to T4. The primary outcome measured was overall survival (OS). OS univariate analyses were conducted using the Kaplan-Meier method; multivariate survival analyses were performed using Cox proportional hazards ratios. Results: 1909 incident cases of histologically-confirmed BAC were analyzed. Using the proposed criteria, 162 (25%) of the 654 advanced BAC cases were reclassified: 73 cases with multiple lesions in the same lobe as T3 (stage II T3N0M0 [n=53] or T3NXM0 [n=1], stage IIIA T3N1–2M0 [n=18], stage IIIB T3N3M0 [n=1]); 89 cases with ipsilateral intrapulmonary metastasis were reclassified as T4 (stage IIIB, T4N1- 3M0). Univariate OS analysis of this validation set reveals an improved fit for the proposed staging system compared to the existing staging system ( Table 1 ). Analysis by stage reveals improvement in this proposed prognostic model over the existing staging system on multivariate survival analysis after adjustment for relevant clinicopathologic variables ( Table ). Conclusions: Our proposed BAC staging system modifications more accurately reflect survival characteristics for this unique type of non-small-cell lung cancer.

[Table: see text]

A novel intermediate endpoint for predicting overall survival in men with metastatic castration-recurrent prostate cancer (CRPC)

5113

Background: In this proposed study, we developed and validated a novel composite clinical benefit endpoint constructed from symptoms that have intrinsic clinical importance in 800 men with CRPC who were treated with front-line chemotherapy. Methods: Data from nine multimember trials (five phase II and four randomized phase III studies) conducted by the Cancer and Leukemia Group B (CALGB) from 1992–2004 were combined. Eligible patients had progressive adenocarcinoma of the prostate during androgen ablation (despite castrate testosterone levels), an ECOG performance status of 0–2, adequate hematologic, renal and hepatic functions. The tripartite composite clinical benefit endpoint (TCCBE) had three components: one based on disease progression (whether it be PSA, bone, or soft tissue progression), and the second based on weight loss (defined as at least 10% decline from baseline) or on performance status (PS) decline (by at least one level) to capture clinical deterioration. The third component was based on pain control and opioid analgesic use (no or yes). For a person to fall in the TCCBE “yes” category, at least two of the three components had to be recorded as no. For instance, if a patient at 3 months had no progression, no change in weight and did not use opioid analgesic, then he will be classified in the “yes” group and for the purpose of this analysis was considered as someone who achieved “clinical benefit”. The sample was randomly split into 526 (67%) and 274 (33%) men in the training and testing datasets, respectively. Results: From the training dataset, the median survival times in men who had and did not have clinical benefit were 20.9 months (95% confidence interval (CI) = 18.5–22.8) and 11.1 months (95% = 8.79–12.6, p- value<0.001). In the testing dataset, the median survival times in men with and without clinical benefit were 21.7 months (95% CI= 19.1–26.1) and 8.8 months (95% CI= 7.8–11.6) and in men. The hazard ratio (HR) for men with a clinical benefit compared to men without was 0.52 (95% CI= 0.43–0.62, P<0.001). Conclusions: The TCCBE is a statistically significant intermediate endpoint for predicting overall survival. Prospective validation of this endpoint is needed.

No significant financial relationships to disclose.

An elevated body mass (BMI) index predicts for better clinical outcomes in men with metastatic hormone refractory prostate cancer (HRPC)

4556

Background: Previous articles have reported that an elevated BMI was associated with an increased risk of biochemical failure in hormone sensitive patients. We asked the question as to whether an elevated BMI predicts for worst clinical outcomes, namely overall survival (OS) and prostate-cancer survival (PCS), among 1,216 men with HRPC. Methods: Patients were enrolled on eight clinical trials conducted by the Cancer and Leukemia Group B (CALGB). Eligible patients had progressive prostate cancer during androgen deprivation therapy (with documented castrate levels of testosterone), an ECOG performance status of 0–2, adequate hematologic, renal and hepatic function. We used the NIH definition to classify patients as: normal (<25 kg/m2), overweight (25–29 kg/m2 ), mildly obese (30–34 kg/m2), and moderately to severely obese (≥35 kg/m2). PCS was defined as the time from study entry to the time of death due to prostate cancer. The proportional hazards model was used to explore the prognostic significance of BMI in predicting OS and PCS. Results: The median BMI was 27.7 kg/m2 (inter-quartile range = 25.2–31.0 kg/m2 ). Twenty three percent (285/1216) of the patients had normal BMI, 46% (555/1216) were overweight, 23% (280/1216) were mildly obese, and 8% (96/1216) were moderately to severely obese. In multivariate analysis, adjusting for age, race, performance status, hemoglobin, PSA, LDH, alkaline phosphatase, testosterone, years since diagnosis, presence of visceral disease and Gleason scores, BMI was a statistically significant predictor of OS and PCS. Compared to normal men, the hazard ratios (HR) of overweight patients was 0.80 (95% CI = 0.69–0.93, p-value = 0.003), for mildly obese patients was 0.86 (95% CI = 0.72–1.02, p-value = 0.087) and for moderately to severely obese men it was 0.60 (95% CI = 0.47–0.78, p-value < 0.001). In addition, the HRs for PCS for overweight patients was 0.83 (95% CI = 0.70–0.97, p-value = 0.023), was 0.88 (95% CI = 0.72–1.06, p-value = 0.179) for mildly obese and for moderately to severely obese was 0.62 (95% CI = 0.47–0.81, p-value = 0.001) compared to men with normal BMI. Conclusions: Contrary to what was reported, these findings demonstrate an inverse relationship between BMI and clinical outcomes in men with HRPC.

[Table: see text]

Antibodies against huntingtin: production and screening of monoclonals and single-chain recombinant forms

Antibodies can be extremely useful tools for the field of triplet repeat diseases. These reagents are important for localizing proteins in tissues, and within cells, they can be used in the isolation and characterization of the components of protein complexes, they can distinguish proteins with normal or an expanded polyglutamine repeat, they may be able to distinguish distinct conformations of a protein, and they can be used to perturb the function of proteins in living cells. Our group has produced monoclonal and recombinant single-chain antibodies that can be used for each of these purposes with huntingtin. This is the protein that, when mutated to contain an expanded polyQ motif, causes Huntington's disease.

Production of a novel FK520 analog in Streptomyces hygroscopicus: improving titer while minimizing impurities

FK520, also called ascomycin, is an immunosuppressive agent produced by Streptomyces hygroscopicus. Engineering the polyketide synthase genes of the parent strain generated novel FK520 analogs with the potential for improved in vivo stability. By replacing the acyl transferase (AT) domain in the polyketide synthase module 8 with an AT specific for methylmalonyl CoA (the rapamycin AT 3), the strain produced 13-desmethoxy-13-methyl-FK520 (13dmmFK520). Process development and scale-up studies of this recombinant S. hygroscopicus strain producing 13dmmFK520 are described here. Production kinetics and compound stability in fermentation broth were significantly different compared to the native FK520. Fermentation of the new strain resulted in the synthesis of a contaminating substance that co-purified with the 13dmmFK520. To optimize 13dmmFK520 production and to facilitate purification, growth parameters and media development were examined. Although a medium was identified that increased product titers by ca. 300%, the ratio of impurity to product was doubled. Lower dissolved oxygen (20% compared to 50% and 80%) increased titers by 20% with no appreciable effect on the concentration of impurity. Increasing the fermentation pH from 6.0 to 6.5 did not change the 13dmmFK520 titer, but reduced the impurity-to-product ratio by approximately 450%.

Modulation of epothilone analog production through media design

Recently, the epothilone polyketide synthase (PKS) was successfully introduced into a heterologous production host for the large-scale production of epothilone D. We have found that at least three other epothilones can also be produced as the major fermentation product of this recombinant strain by supplementation of specific substrates to the production media. Addition of acetate or propionate to the media results in modulation of the epothilone D:C ratio, whereas addition of L-serine with either acetate or propionate yields epothilone H(1) or H(2) as the major product. This strategy permits production of at least four novel epothilones by culturing a single host with a genetically modified epothilone PKS in various media.