Quantifying Contact Patterns: Development and Characteristics of the British Columbia COVID-19 Population Mixing Patterns Survey

Purpose

Several non-pharmaceutical interventions such as physical distancing, self-isolation, a stay-at-home order, hand washing, and schools and businesses closures were implemented in British Columbia (BC) following the first lab-tested case of COVID-19 on January 26, 2020. These interventions were aimed at minimizing in-person contacts that could potentially lead to new COVID-19 infections. The BC COVID-19 Population Mixing Patterns survey (BC-Mix) was established as a surveillance system to measure behaviour and contact patterns in BC over time to inform the timing of the easing/re-imposition of control measures. We describe the BC-Mix survey design and the demographic characteristics of respondents.

Methods & Materials

The ongoing repeated online survey was launched in September 2020. Participants are recruited through a variety of social media platforms including Instagram, Facebook, YouTube, and community group mailing lists. A follow up survey is sent to participants two to four weeks after completing the first iteration. Survey responses are weighted to BC's population by age, sex, geography, and ethnicity to obtain generalizable estimates. A survey completion rate of at least 33% AND a valid response for the sex questionnaire item AND a valid response for age questionnaire item were required for inclusion in weighting and further analysis. Additional indices such as material and social deprivation index, and residential instability are generated using census and location data.

Results

As of June 14, 2021, over 58,000 residents of BC had participated in the survey of which 31,007 survey responses were eligible for analysis. Of the eligible participants, about 60% provided consent for monthly follow up and about 26% provided their personal health numbers for linkage with other healthcare utilization databases. Approximately 51% were females 39% were 55 years or older, 63% identified as white or not a visible minority and 48% had at least a university degree.

Conclusion

The pandemic response is best informed by surveillance systems capable of timely assessment of behaviour patterns. BC-Mix survey respondents represented a large cohort of British Columbians providing near real-time information on behavioural and contact patterns in BC. Data from the BC-Mix survey continues to inform provincial COVID-19-related control measures.

A phase I study of the anaplastic lymphoma kinase inhibitor ceritinib in combination with gemcitabine-based chemotherapy in patients with advanced solid tumors

In this phase I, dose-escalation study, we sought to determine the maximum tolerated dose (MTD) of the anaplastic lymphoma kinase/c-ROS oncogene 1 receptor (ALK/ROS1) inhibitor ceritinib in combination with gemcitabine-based chemotherapy in patients with advanced solid tumors. Secondary objectives were characterization of the safety profile, pharmacokinetics and preliminary efficacy of these combinations, and identification of potential biomarkers of efficacy. Ceritinib was combined with gemcitabine (Arm 1), gemcitabine/nab-paclitaxel (Arm 2) or gemcitabine/cisplatin (Arm 3). Drug concentrations in plasma were measured by tandem mass spectrometric detection (LC-MS/MS). We analyzed archival tumor tissue for ALK, ROS1, hepatocyte growth factor receptor (c-MET) and c-Jun N-terminal kinase (JNK) expression by immunohistochemistry. Arm 2 closed early secondary to toxicity. Twenty-one patients were evaluable for dose-limiting toxicity (DLT). There was one DLT in Arm 1 (grade 3 ALT increase) and three DLTs in Arm 3 (grade 3 acute renal failure, grade 3 thrombocytopenia, grade 3 dyspnea). The MTD of ceritinib was determined to be 600 mg (Arm 1) and 450 mg orally daily (Arm 3). Main toxicities were hematologic, constitutional and gastrointestinal as expected by the chemotherapy backbone. The apparent clearance for ceritinib decreased substantially after repeated dosing; cisplatin did not significantly affect the pharmacokinetics of ceritinib. The overall response rate was 20%; the median progression-free survival was 4.8 months. Three out of five response-evaluable cholangiocarcinoma patients had clinical benefit. Increased expression of c-MET was associated with a lack of clinical benefit. Ceritinib in combination with gemcitabine and gemcitabine/cisplatin has a manageable toxicity profile. Further development of this strategy in tumors with ALK or ROS1 fusions is warranted.

Phase Ib Study of Enzalutamide with or Without Sorafenib in Patients with Advanced Hepatocellular Carcinoma

LESSONS LEARNED

Androgen receptor as assessed by immunohistochemistry is expressed in a high proportion of patients with hepatocellular carcinoma (HCC). Enzalutamide at 160 mg orally daily is safe and tolerable in patients with advanced HCC but has no single-agent antitumor activity. Enzalutamide, a CYP3A4 inducer, at a standard dose of 160 mg reduces the exposure of sorafenib, a CYP3A4 substrate. Enzalutamide and sorafenib is safe and tolerable in patients with advanced HCC, but the addition of enzalutamide to sorafenib did not enhance the antitumor activity of sorafenib.

BACKGROUND

Androgen receptor (AR) interference is deleterious to hepatocellular carcinoma (HCC) in preclinical models.

METHODS

This is a multicenter, phase Ib study of enzalutamide ± sorafenib in patients with advanced HCC. In part 1, a 3 + 3 dose de-escalation design with expansion established the recommended phase II dose (RP2D) of enzalutamide in patients in whom sorafenib treatment had failed. In part 2, a 3 + 3 dose escalation with expansion established the safety of enzalutamide with sorafenib in treatment-naive patients with HCC. Secondary objectives included objective response rate (ORR), progression-free survival (PFS), overall survival (OS), pharmacokinetics (PK), and determination of AR expression by immunohistochemistry. A 7-day run-in with sorafenib alone in part 2 allowed assessment of the impact of enzalutamide on sorafenib pharmacokinetics.

RESULTS

In part 1, 16 patients received enzalutamide 160 mg daily. No dose-limiting toxicity (DLT) occurred; 1 patient required dose reduction. Responses were not observed; median PFS and OS were 1.8 (95% confidence interval [CI]: 1.6-3.6) and 7 (95% CI: 3.6 to not reached [NR]) months, respectively. In part 2, patients received sorafenib 400 mg daily (4) or twice a day (8) both with enzalutamide at the recommended phase II dose-no DLTs were observed. ORR was 10% (95% CI: 0.3-44.5), and median PFS and OS were 2.9 (95% CI: 1.6 to NR) and 6.7 (95% CI: 4.6 to NR) months, respectively. Enzalutamide reduced sorafenib exposure by 60%. Tumor AR expression did not associate with outcome.

CONCLUSION

Enzalutamide is ineffective in HCC; further development is not supported by this study.

Abstract CT139: Ceritinib (Cer) in combination with gemcitabine (Gem)-based chemotherapy in patients (pts) with advanced solid tumors, a phase I study

Introduction: Cer is an oral ALK/ROS1 inhibitor. Aberrancies in ALK and ROS1 have been observed in many cancer types and ALK inhibition has synergistic effects with chemotherapy in ALK or ROS1 rearranged tumors in preclinical models. We launched a Phase I study of Cer in combination with Gem-based chemotherapy in advanced solid tumors. Herein we present initial results of this study. Methods: Phase I, dose-escalation study of Cer in combination with A1: Gem 1000 mg IV D1/8/15 q28 days; A2: Gem 1000 mg IV + nanoparticle albumin-bound Paclitaxel 125 mg IV both D1/8/15 q28 days; A3: Gem 1000 mg IV + Cisplatin 60 mg IV D1/8 q21 days in pts with advanced, solid malignancies until disease progression, intolerable toxicity or withdrawal. A 3 + 3 dose-escalation design was used starting at Cer 450 mg once daily (DL1) in all arms; DL2 was 600 mg once daily. Primary objective was to determine the maximum tolerated dose (MTD) of Cer. Key inclusion criteria: diagnosis of advanced solid malignancy for which Gem-based treatment was appropriate, >18 years old, ECOG PS 0/1, adequate bone marrow/renal/liver function. Key exclusion criteria: interstitial lung fibrosis/disease, recent acute coronary event, CHF NYHA III/IV, corrected QTc > 450 ms. Pts in A3 could have up to 2 prior lines of therapy. Prior use of ALK inhibitors allowed. Plasma was collected for PK on C1D1, C2D1, and C1D15. Archival tumor tissue was tested for ALK/ROS1/JNK/MET by IHC. Results: Thirty-eight patients were enrolled with 21 evaluable for dose-limiting toxicity (DLT) in A1 and A3. A2 (n=4) closed to accrual for toxicity. Median age was 61 years. Seven pts (41%) had cholangiocarcinoma. A1 had one DLT (G3 ALT increase) in DL2; MTD was 600 mg. A3 had one DLT in DL1 (G3 acute renal failure) and two DLTs in DL2 (G3 thrombocytopenia and G3 dyspnea); MTD was 450 mg. G3-5 AEs in all pts: anemia (A1: 3/19, A3: 2/15), nausea (A1: 1/19, A3: 2/15), emesis (A1: 1/19, A3: 1/15), neutropenia (A1: 2/19, A3: 8/15), thrombocytopenia (A1: 1/19, A3: 4/15), hyperbilirubinemia (A3: 3/15), pneumonia (A1: 2/19), acute renal failure (A3: 1/15), fatigue (A3: 2/15). Fifteen patients were evaluable for response; the overall response rate was 20% with two PR (pt with head and neck carcinoma in A1 and pt with carcinoma of unknown primary in A3) - and one CR in a pt with cholangiocarcinoma (A3) lasting 10.3 months. Overall, disease control rate was 47%. Of 5 evaluable pts with cholangiocarcinoma 3 had clinical benefit. Median PFS 3.4 mo (A1)/4.8 mo (A3) and OS 13.7 mo (A1)/29.1 mo (A3). PK and IHC data will be presented at the conference. Conclusions: The MTD of Cer is 600 mg in combination with Gem and 450 mg in combination with Gem/Cisplatin. Further evaluation of Cer plus Gem-based chemotherapy is planned in ALK/ROS1 positive cholangiocarcinomas.

Citation Format: Christos Fountzilas, Alex Adjei, Mateusz Opyrchal, Rachel Evans, Kristopher Attwood, Andrew Goey, John Wilton, Wen Wee Ma, Renuka Iyer. Ceritinib (Cer) in combination with gemcitabine (Gem)-based chemotherapy in patients (pts) with advanced solid tumors, a phase I study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT139.

Multicenter phase 2 trial of nintedanib in advanced nonpancreatic neuroendocrine tumors

BACKGROUND

Antiangiogenic-targeting agents have low response rates in patients with nonpancreatic neuroendocrine tumors (NETs). Nintedanib is an oral antiangiogenic agent that has inhibitory effects on the fibroblast growth factor receptor, which is highly expressed in NETs. The authors hypothesized that nintedanib would be active in patients with nonpancreatic NETs.

METHODS

Patients with advanced, grade 1 or 2, nonpancreatic NETs who were receiving a stable dose of somatostatin analogue were enrolled. Nintedanib was administered at a dose of 200 mg twice daily in 28-day cycles. The primary endpoint was progression-free survival (PFS) at 16 weeks.

RESULTS

Thirty-two patients were enrolled, and 30 were evaluable for the primary outcome. Most had radiographic disease progression within 12 months before enrollment. The 16-week PFS rate was 83%, and the median PFS and overall survival were 11.0 months and 32.7 months, respectively. Nintedanib was well tolerated and delayed deterioration in quality of life. The baseline serotonin level had a strong, positive correlation with activated but exhausted T cells.

CONCLUSIONS

Nintedanib is active in nonpancreatic NETs. The immunosuppressive effect of serotonin should be targeted in future clinical trials.

Abstract B087: Role of GATA-4-Androgen-AR axis in prostate cancer from African American men

Background: African American (AA) men are 1.7 times more likely to develop and 2.4 times more likely to die of prostate cancer (PrCa) than their European American (EA) counterparts, however the underlying biology causing this disparity is unknown. Here, we show how epigenetic dysregulation of calcium signaling genes affect GATA-4, androgen receptor (AR), androgen metabolism and associate with clinical outcomes in AA men with PrCa. Methods: Using Illumina arrays we identified DNA methylation differences between 32 EA and AA PrCa patients. We used RNA-sequencing to discover transcriptomic changes potentially mediated by DNA methylation. We measured GATA-4 and AR protein expression in a tissue microarray (TMA) of 95 EA and 92 AA PrCa patients. We measured testosterone (T) and dihydrotestosterone (DHT) in serum of the same AA and EA PrCa patients. In vitro, we treated MDA PCa 2a (2a) and LaPC4 cells derived from AA and EA prostate tumors, respectively with a calcium chelator (BAPTA-AM) and T. We measured GATA-4 and AR protein expression in control and treated cells. Results: Our DNA methylation analysis showed that AA but not EA prostate tumors enriched for hypermethylated sites in calcium sensing genes was associated with worse disease-free time (21.6 vs 46.7 months, p<0.05). DNA hypermethylation of calcium signaling genes, which correlated with decreased transcript levels, can potentially raise intracellular calcium. Calcium levels regulate stability of proteins including AR and GATA-4. Therefore, we tested potential calcium mediated changes in GATA-4 and AR expression in vitro and in patient samples. In vitro, depleting calcium in the presence of T increased GATA-4 protein expression by 1.5 times and AR expression only in AA prostate tumor derived 2a cells. DNA hypermethylation of calcium sensing genes was associated with lower GATA-4 and AR expression in PrCa and adjacent non-tumor tissues of AA men. The role of GATA-4 in PrCa is unknown, but it is a known transcriptional regulator of androgen metabolizing enzymes (AME). AMEs are important for androgen metabolism that result in T and DHT production through the primary and alternative pathways. AME transcripts in the primary and alternative pathways were one of the top 5 transcriptionally dysregulated pathways in AA compared to EA prostate tumors. We found that T but not DHT is significantly lower (p<0.05) in serum samples from AA (3.64ng/ml) compared to EA (3.99ng/ml) PrCa patients. T and DHT bioavailability in prostate tumors affect AR expression and function. In our studies, AA adjacent non-tumor tissues had higher percent AR positive nuclei (p<0.05) compared to EA adjacent non-tumor tissues. Conclusion: Epigenetic alteration of calcium signaling can affect GATA-4 mediated changes in androgen metabolism and AR signaling that are well-established therapeutic targets in PrCa. This molecular alteration, unique to AA prostate tumors, can be used to rationalize specific androgen deprivation and AR-targeted therapies in these patients.

Citation Format: Swathi Ramakrishnan, Xuan Peng, Eduardo Cortes Gomez, Kristopher Attwood, Li Yan, John Wilton, Gissou Azabdaftari, James Mohler, Jianmin Wang, Anna Woloszynska. Role of GATA-4-Androgen-AR axis in prostate cancer from African American men [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr B087.

Diet and lupus: what do the patients think?

Objectives

Cardiovascular disease is the leading cause of mortality in patients with systemic lupus erythematosus. Therefore, using diet to control blood lipid levels and modify cardiovascular disease risk could be a promising therapeutic strategy to control disease symptoms. The primary objective of this study was to learn about systemic lupus erythematosus patient experiences with diet, including their opinion on considering diet as a therapeutic option. The secondary objective was to obtain this information in a cost- and time-effective manner.

Methods

A lay summary and a 15-question diet-based online survey were publicly available for 3 weeks. Social media was used to promote the survey through relevant charities, hospitals and research groups.

Results

A total of 300 responses were received, 284 from patients with systemic lupus erythematosus. Patients reported that there was a lack of clinical counselling regarding diet, with only 24% stating their doctor had spoken to them about diet. Despite this, 100% of patients stated they would change their diet if they knew it would help their symptoms and 83% would take part in a future diet-based clinical trial. Text analysis of patient research suggestions identified a particular interest in using diet to treat fatigue and manage disease flares.

Conclusions

This project successfully gathered patient information regarding diet and systemic lupus erythematosus over a short timeframe using an anonymous social media platform. The survey provided evidence that patients support further research and potential diet intervention studies investigating the effect of diet on the symptoms of systemic lupus erythematosus.

Late diagnosis, delayed presentation and late presentation among persons enrolled in a clinical HIV cohort in Ontario, Canada (1999-2013)

OBJECTIVES

Timely HIV diagnosis and presentation to medical care are important for treatment and prevention. Our objective was to measure late diagnosis, delayed presentation and late presentation among individuals in the Ontario HIV Treatment Network Cohort Study (OCS) who were newly diagnosed in Ontario.

METHODS

The OCS is a multi-site clinical cohort study of people living with HIV in Ontario, Canada. We measured prevalence of late diagnosis [CD4 count < 350 cells/μL or an AIDS-defining condition (ADC) within 3 months of HIV diagnosis], delayed presentation (≥ 3 months from HIV diagnosis to presentation to care), and late presentation (CD4 count < 350 cells/μL or ADC within 3 months of presentation). We identified characteristics associated with these outcomes and explored their overlap.

RESULTS

A total of 1819 OCS participants were newly diagnosed in Ontario from 1999 to 2013. Late diagnosis (53.0%) and presentation (54.0%) were common, and a quarter (23.1%) of participants were delayed presenters. In multivariable models, the participants of delayed presentation decreased over calendar time, but that of late diagnosis/presentation did not. Late diagnosis contributed to the majority (> 87%) of late presentation, and the prevalence of delayed presentation was similar among those diagnosed late versus early (13.4 versus 13.4%, respectively; P = 0.99). Characteristics associated with higher odds of late diagnosis/presentation in multivariable analyses included older age at diagnosis/presentation; African, Caribbean and Black race/ethnicity; Indigenous race/ethnicity; female sex; and being a male who did not report sex with men. There were lower odds of late diagnosis/presentation among participants who had ever injected drugs. In contrast, delayed presentation risk factors included younger age at diagnosis and having ever injected drugs.

CONCLUSIONS

Late presentation is common in Ontario, as it is in other high-income countries. Our findings suggest that efforts to reduce late presentation should focus on facilitating earlier diagnosis for the populations identified in this analysis.

Guided self-help to manage binge eating in a dietetic-led community weight management service

An estimated 30% of patients accessing community weight management services experience symptoms of binge eating disorder (BED). Guided self-help (GSH) is the recommended first line of treatment for BED. This study is a preliminary investigation into the effectiveness of GSH delivered by dietitians for patients with binge eating within a weight management service and a consideration of the association between wellbeing, therapeutic relationship and outcomes. The study was conducted as a single group, pre- and post-intervention study with 24 patients reporting symptoms of binge eating who completed the self-help manual with guidance from a trained community dietitian. Primary outcomes were eating disorder psychopathology and behaviours (Eating Disorder Evaluation Questionnaire), depression and anxiety. Principle results showed a significant reduction on all subscales of eating disorder psychopathology, anxiety and depression. There was a reduction in loss of control over eating but the 40% reduction in binge episodes was not statistically significant. Mid-treatment sessional ratings were positively associated with outcome. In conclusion, the GSH intervention was appropriate for dietitian delivery to patients with obesity and binge eating behaviour. This research indicates potential for other dietetic-led weight management services to deliver such interventions and support patients with binge eating accessing their service.

Dehydroepiandrosterone in metastatic castration-resistant prostate cancer: Preliminary results from the SU2C-PCF West Coast Dream Team (WCDT)

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Background: Aberrant androgen receptor (AR) phenotypes (e.g. splice variants, amplification) are strongly correlated with abiraterone (Abi) and enzalutamide (Enz) resistance. Low serum dehydroepiandrosterone (DHEA) is also associated with poor outcomes to AR-targeted therapy. Here, we investigate the relationship between serum DHEA, AR phenotype, and treatment efficacy in the WCDT. Methods: Patients (pts) with progressive mCRPC enrolled to the WCDT from UCSF, OHSU, UCLA, UBC, and UCD were included in this analysis. Serum DHEA was analyzed via high-pressure liquid chromatography and tandem mass spectrometry. Limit of quantitation (LQ) of DHEA was 0.2ng/mL. Full-length AR (AR-FL) and AR-v7 expression, obtained via RNAseq of metastatic tumor biopsies, was expressed as total reads mapped to gene. PSA response (PSAr) was defined as ≥ 50% PSA decline. Results: 35 pts were included in this analysis: 15 had treatment-naïve mCRPC, and 20 had prior AR-targeted therapy (14 Abi, 6 Enz). All pts were docetaxel-naïve. 11 pts had DHEA < LQ; of these, 10 had received prior AR-targeted therapy. 12 pts received subsequent chemotherapy, and 23 received subsequent Abi/Enz (7 Abi, 16 Enz). In pts with DHEA < LQ, 4/5 (80%) chemotherapy-treated pts had PSAr, while 1/6 (17%) Abi/Enz-treated pts had PSAr. In pts with DHEA ≥ LQ, 2/7 (27%) chemotherapy-treated pts had PSAr, while 9/16 (56%) Abi/Enz-treated pts had PSAr. The relationship between DHEA and PSAr was significantly different between the treatment groups (p = 0.0285). DHEA was higher in patients with PSAr to Abi/Enz versus those without PSAr (median, 0.871 versus 0.275ng/mL, p = 0.006). In an analysis of 27 pts with RNAseq data, the AR-v7/AR-FL ratio was significantly higher in those with DHEA < LQ (median ratio 8.91, versus 3.38 in DHEA ≥ LQ, p = 0.032). Conclusions: In this exploratory analysis, there is a significant difference in the relationship between DHEA and PSAr in chemotherapy- versus Abi/Enz-treated patients. DHEA < LQ was also associated with a higher AR-v7/AR-FL ratio, a potential avenue for further exploration of tumor biology. These results support a larger study to evaluate DHEA as a potential biomarker in mCRPC. Clinical trial information: NCT02432001.

The Anatomical Society core regional anatomy syllabus for undergraduate medicine

The Anatomical Society's core syllabus for anatomy (2003 and later refined in 2007) set out a series of learning outcomes that an individual medical student should achieve on graduation. The core syllabus, with 182 learning outcomes grouped in body regions, referenced in the General Medical Council's Teaching Tomorrow's Doctors, was open to criticism on the grounds that the learning outcomes were generated by a relatively small group of anatomists, albeit some of whom were clinically qualified. We have therefore used a modified Delphi technique to seek a wider consensus. A Delphi panel was constructed involving 'experts' (n = 39). The revised core syllabus of 156 learning outcomes presented here is applicable to all medical programmes and may be used by curriculum planners, teachers and students alike in addressing the perennial question: 'What do I need to know ?'

Pharmacokinetic analysis of the FAK scaffold inhibitor C4 in dogs

Inhibition of focal adhesion kinase-vascular endothelial growth factor receptor 3 complex by C4 was previously shown to reduce tumor growth alone and synergistically with other chemotherapeutic agents in animal tumor models. Single and multiple dose IV and oral dosing studies were performed in dogs to determine C4 pharmacokinetics. C4 was administered to 4 dogs at 1.25 or 2.50 mg/kg IV, or 7.50 mg/kg oral gavage. Single- (IV and oral) and multiple- (IV) dose pharmacokinetic samples were collected on days 1 and 3 at pre-dose and 0.5, 1, 2, 4, 8, 24, 120, 144, and 168 h post-dose. C4 concentrations were determined using liquid chromatography with tandem mass spectral detection with a limit of quantitation of 2.50 pg/mL. Pharmacokinetics of C4 was characterized by a 3-compartment model with linear distributional and elimination clearances using Phoenix 64 WinNonlin 6.3. Mean C4 plasma concentration-time profiles revealed a triexponential decline following either IV or oral administration, independent of dose with no accumulation. For the 2.5 mg/kg dose, the median half-life was ~21 h. Median C max and area under the curve (AUC0-24) were similar for days 1 and 3. Oral bioavailability for formulations of PBS, TPGS, Maalox(®), and Pepcid(®) was greatest with TPGS (45 %), followed by Maalox(®) (42 %), Pepcid(®) (37 %), and PBS (30 %). The pharmacokinetic study revealed that C4 has linear pharmacokinetics and does not accumulate following multiple-dose administration. Characterization of C4 pharmacokinetics provides a better understanding of the novel targeted agent, which will help facilitate further development of C4.

Roles for the backdoor pathway of androgen metabolism in prostate cancer response to castration and drug treatment

Almost all men who present with advanced prostate cancer (CaP) and many men who fail potentially curative therapy are treated with androgen deprivation therapy (ADT). ADT is not curative and CaP recurs as the lethal phenotype. The goal of this review is to describe the evolution of adrenal androgen blockade, how new androgen measurement methods have furthered understanding of androgen metabolism, and how further understanding of the backdoor pathway of androgen metabolism may lead to interventions that extend survival even more.

A pilot study comparing the effect of flaxseed, aromatase inhibitor, and the combination on breast tumor biomarkers

Use of complementary approaches is common among breast cancer survivors. Potential interactions between aromatase inhibitors (AI) and high phytoestrogen foods, such as flaxseed (FS), are not often described. We conducted a pilot 2 × 2 factorial, randomized intervention study between tumor biopsy and resection, in 24 postmenopausal women with estrogen receptor positive (ER+) breast cancer, to assess the effects of FS and anastrozole, and possible interactions between them, on serum steroid hormone and tumor-related characteristics associated with long-term survival (Roswell Park Cancer Institute, 2007-2010). The effect of each treatment vs. placebo on outcomes was determined by linear regression adjusting for pretreatment measure, stage, and grade. Although not statistically significant, mean ERβ expression was approximately 40% lower from pre- to postintervention in the FS + AI group only. We observed a statistically significant negative association (β ± SE -0.3 ± 0.1; P = 0.03) for androstenedione in the FS + AI group vs. placebo and for DHEA with AI treatment (β ± SE -1.6 ± 0.6; P = 0.009). Enterolactone excretion was much lower in the FS + AI group compared to the FS group. Our results do not support strong effects of FS on AI activity for selected breast tumor characteristics or serum steroid hormone levels but suggest AI therapy might reduce the production of circulating mammalian lignans from FS.

Activity of abiraterone acetate in metastatic patients with castration-resistant prostate cancer (mCRPC) previously treated with ketoconazole: A prospective phase II study from the prostate cancer clinical trials consortium

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Background: Abiraterone acetate (AA), like ketoconazole (keto), inhibits CYP17, the rate-limiting enzyme in androgen biosynthesis. Since patients (pts) with prior keto treatment were excluded from the pivotal phase III AA trials, the utility of AA after keto is not well understood. This prospective study evaluated the efficacy of AA in pts who had received prior keto. Methods: Pts with progressive castration-resistant prostate cancer (mCRPC), prior keto therapy 28 days or more, and normal baseline organ function (including ACTH stimulation) tests were treated with AA 1,000 mg PO daily and prednisone 5 mg PO BID. Pts with prior chemotherapy were excluded. Serum androgen levels, including dehydroepiandrosterone (DHEA), were measured by liquid chromatography/mass spectroscopy (LC/MS) at baseline and during treatment for exploratory analyses. Radiographic progression-free survival (rPFS) was defined as freedom from: death, radiographic progression, or unequivocal clinical progression. Results: Forty two pts were enrolled. Median age was 71. Median prostate-specific antigen (PSA) was 47.5ng/dL. Median duration of prior keto was 38 weeks (range 5 to 207). Treatment with AA resulted in 30% or greater decline in PSA at 12 weeks in 20 pts (48%, 95% CI, 32-63%), and 50% or greater decline in PSA at 12 weeks in 16 pts (38%, 95% CI 24-54%). Median time to PSA progression (TTPP) was 16 weeks (range 4 to 64). Median rPFS was 24 weeks (range 1 to 88). Baseline serum DHEA levels were measured in 40 pts. Nine pts had DHEA less than the limit of quantitation (LOQ, 0.250ng/mL), and 31 pts had DHEA greater than or equal to LOQ. One pt with DHEA less than LOQ (1 out of 9, 11%, 95% CI 0.6-49%) had PSA decline 30% or more at 12 weeks, compared to 17 pts (17 out of 31, 55%, 95% CI 36-72%) with DHEA greater than or equal to LOQ (p=0.028). Median time to pain progression (TTPP) was 8 weeks (range 4 to 32) for pts with DHEA less than LOQ, compared to 18 weeks (range 4 to 64) for pts with DHEA greater than or equal to LOQ (p=0.012). Median rPFS was 12 weeks (range 4 to 24) for pts with DHEA less than LOQ, compared to 36 weeks (range 1 to 88) for pts with DHEA greater tha or equal to LOQ (p = 0.0006). Six pts remain on AA. Conclusions: A significant proportion of pts with prior keto exposure demonstrate clinical response to AA. DHEA levels via LC/MS merits further study as a predictive biomarker in pts treated with androgen synthesis inhibitors. Clinical trial information: NCT01199146.

Abstract 3372: Pharmacokinetic analysis of CFAK-C4 in dogs and estimation of first dose in man

Purpose: Inhibition of the FAK-VEGFR-3 interaction by the small molecule inhibitor chloropyramine hydrochloride (CFAK-C4) has been shown to reduce tumor growth both alone and synergistically with doxorubicin and gemcitabine in an animal tumor model. A multiple dose study of CFAK-C4 in dogs was investigated to gain knowledge in estimating a first in man dose. Methods: CFAK-C4 was given to two female and two male dogs as an IV infusion at 1.25 or 2.5 mg/kg for five minutes, on three consecutive days, days 1, 2 and 3. Single- and multiple-dose PK samples were collected on days 1 and 3 of dosing. Plasma samples were collected at 0.5, 1, 2, 4, 8, and 24 hours post-dose. CFAK-C4 concentrations were determined using LC-MS/MS, with a LLOQ of 2.5 pg/ml. Noncompartmental PK analysis was performed using WinNonlin (Pharsight, version 5.3).

Results: The mean CFAK-C4 plasma concentration-time profiles revealed a biexponential decline of drug following IV infusion, independent of day of dosing. The median (range) half-life was 3.42 hours (2.75-4.06 hours) and 3.79 (3.5-5.0) on days 1 and 3 following administration of 1.25 mg/kg CFAK-C4. At the 2.5 mg/kg dose level, the median half-life was similar. The median (range) Cmax of 1.25 mg/kg CFAK-C4 was determined to be 75 ng/ml (41-87 ng/ml) on day 1 and 99 ng/ml (84-102 ng/ml) on day 3. After the 2.5 mg/kg dose the Cmax was 185 ng/ml (165-244 ng/ml) and 171 ng/ml (153-181 ng/ml) on days 1 and 3 respectively. The AUC0-24 at the 1.25 mg/kg dose level was similar on both days 1 and 3 with a median (range) of 167 ng*hr/ml (117-231 ng*hr/ml) and 178 ng*hr/ml (170-194 ng*hr/ml), respectively. The AUC0-24 was also similar after the 2.5 mg/kg dose on days 1 and 3 with a median (range) of 447 ng*hr/ml (434-495 ng*hr/ml) and 406 ng*hr/ml (400-460 ng*hr/ml), respectively. The median (range) clearance for dose 1.25 mg/kg was 7.46 L/hr/kg (5.36-10.59 L/hr/kg) on day 1 and 6.47 L/hr/kg (6.07-6.91L/hr/kg) on day 3. For the 2.5 mg/kg dose level, the median (range) clearance was slightly lower compared with the 1.25 mg/kg dose, with values of 5.48 L/hr/kg (5.02-5.66 L/hr/kg) and 5.85 L/hr/kg (5.04-5.93 L/hr/kg) on days 1 and 3, respectively. Utilizing allometric scaling techniques of PK parameters from mice and dogs for CFAK-C4, the estimated human PK parameters for volume of distribution, clearance and half-life were 1695 L, 126 L/hr, and 9.34 hours, respectively. Subsequently, using a no observable adverse event level (NOAEL) of 44.5 mg/kg IP for mice and a NOAEL of 2.5 mg/kg IV for dog, the human starting dose (assuming a 70 kg human) would be a daily dose of 25 mg and 10 mg based on mouse or dog, respectively. Given that dogs are the most sensitive species, 10 mg daily is the suggested first dose in man for CFAK-C4. Conclusions: These results demonstrate that CFAK-C4 has linear kinetics and that no accumulation of drug occurs after multiple dosing. Allometric scaling of mouse and dog data allowed for the estimation of the first in man dose of CFAK-C4.

Citation Format: Allison Gaudy, John Wilton, Leslie Curtin, Elena Kurenova, Sandra Buitrago, William Cance, Gerald Fetterly. Pharmacokinetic analysis of CFAK-C4 in dogs and estimation of first dose in man. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3372. doi:10.1158/1538-7445.AM2013-3372

Phase I and II study of the safety, virologic effect, and pharmacokinetics/pharmacodynamics of single-dose 3-o-(3',3'-dimethylsuccinyl)betulinic acid (bevirimat) against human immunodeficiency virus infection

Bevirimat [3-O-(3',3'-dimethylsuccinyl)betulinic acid] is the first in a new class of anti-human immunodeficiency virus (HIV) drugs that inhibit viral maturation by specifically blocking cleavage of the Gag capsid (CA) precursor, CA-SP1, to mature CA protein, resulting in defective core condensation and release of immature noninfectious virions. Four cohorts of six HIV-infected adults, with CD4 counts of >200 and plasma viral loads of 5,000 to 250,000 transcripts/ml and not currently receiving antiretroviral therapy, were randomized to receive a single oral dose of placebo, 75, 150, or 250 mg of bevirimat. Thirty blood samples for drug concentrations and 20 HIV RNA measures were collected from each subject over a 20-day period. Candidate pharmacokinetic/pharmacodynamic models were fit to individual subjects by maximum likelihood followed by Bayesian estimation; model discrimination was by corrected Akaike's Information Criterion. The bevirimat pharmacokinetics was well described by an oral two-compartment linear model (r(2), 0.98), with a mean (percent coefficient of variation) half-life of 60.3 (13.6) h and apparent oral clearance of bevirimat from the plasma compartment of 0.17 (18) liters/h. HIV RNA was modeled as being produced in infected CD4 cells, with bevirimat inhibiting infection of new CD4 cells thru a Hill-type function (r(2), 0.87). Single oral doses of bevirimat were well tolerated and demonstrated a dose-dependent reduction in viral load. The average maximum reduction from baseline following the 150- and 250-mg doses was greater than 0.45 log(10), with individual patients having reductions of greater than 0.7 log(10). No bevirimat resistance mutations were detected during the course of the study.

Safety and pharmacokinetics of Bevirimat (PA-457), a novel inhibitor of human immunodeficiency virus maturation, in healthy volunteers

Bevirimat (BVM; formerly known as PA-457) is a novel inhibitor of human immunodeficiency virus (HIV) maturation that is being developed for the treatment of HIV infection. The pharmacokinetics of this agent in healthy male volunteers were studied in a randomized, double-blind study in which the participants received single oral doses of placebo (n = 8) or escalating doses of BVM at 25, 50, 100, or 250 mg (n = 6 per dose); escalation was performed only after the pharmacokinetics and safety of the preceding dose had been evaluated. Plasma was collected over 480 h after dosing and urine was collected over 48 h after dosing for determination of the values of pharmacokinetic parameters. BVM was well absorbed after oral administration, with peak plasma concentrations being achieved 1 to 3 h after dosing. The half-life was 60 to 80 h. The exposure assessed by determination of the peak concentration and the area under the concentration-time curve was dose proportional. Single oral doses of BVM were well tolerated: there were no dose-limiting toxicities, and no serious adverse events were reported. These findings suggest that that BVM offers a favorable pharmacokinetic profile, with predictable pharmacokinetics following the oral administration of single doses. The long half-life of BVM may facilitate once-daily dosing.

IBC's conference on antibody engineering; new technology, application and commercialisation

This was the first antibody engineering conference held by IBC Conferences in the UK, and was the European equivalent of the annual US meeting held in San Diego. The conference provided a forum for an update on progress in all aspects of antibody engineering. Topics covered ranged from the design of libraries and new selection techniques to news of the first engineered antibodies to enter clinical trials. Library size and diversity were shown to have increased dramatically in the last few years, and new formats have been introduced. In parallel, improvements to existing applications and the development of novel selection technologies were shown to improve accessibility to new targets. Exciting developments included phenotypic selections, ribosome display, improvements to bispecific design and the design of active intracellular antibodies. The data generated for recombinant antibodies in the clinic are very promising, with some antibodies demonstrating improvements over conventional therapies and others targeting diseases where no treatment is currently available. Presented below is a summary of the highlights of the conference, with particular focus on natural antibody phage libraries, and lead candidates derived from these libraries currently in clinical trials.

Outcome measures for evaluation of scar: a literature review

The number of interventions and the related costs of management of scar are increasing. Despite increasing emphasis on evidence-based practice, there is little comparative data on which to base treatment selection. The ability of a therapist to evaluate the natural progression of a scar or treatment efficacy may be hampered by the nature of the particular scar, the lack of conformity in descriptions of scar, and the lack of reliable standardized outcome measurements. This literature review seeks to clarify the constructs measured for scar and present the measures currently available for use.

A fully human antibody neutralising biologically active human TGFbeta2 for use in therapy

Phage display provides a methodology for obtaining fully human antibodies directed against human transforming growth factor-beta (TGFbeta) suitable for the treatment of fibrotic disorders. The strategy employed was to isolate a human single chain Fv (scFv) fragment that neutralises human TGFbeta2 from a phage display repertoire, convert it into a human IgG4 and then determine its TGFbeta binding and neutralisation properties and its physical characteristics. Several scFv fragments binding to TGFbeta2 were isolated by panning of an antibody phage display repertoire, and subsequent chain shuffling of the selected V(H) domains with a library of V(L) domains. The three most potent neutralising antibodies were chosen for conversion to IgG4 format. The IgG4 antibodies were ranked for their ability to neutralise TGFbeta2 and the most potent, 6B1 IgG4, was chosen for further characterisation. 6B1 IgG4 has a high affinity for TGFbeta2 with a dissociation constant of 0.89 nM as determined using the BIAcore biosensor and only 9% cross-reactivity with TGFbeta3 (dissociation constant, 10 nM). There was no detectable binding to TGFbeta1. 6B1 IgG4 strongly neutralises (IC50 = 2 nM) the anti-proliferative effect of TGFbeta2 in bioassays using TF1 human erythroleukaemia cells. Similarly, there was strong inhibition of binding of TGFbeta2 to cell surface receptors in a radioreceptor assay using A549 cells. 6B1 IgG4 shows no detectable cross-reactivity with related or unrelated antigens by immunocytochemistry or ELISA. The 6B1 V(L) domain has entirely germline framework regions and the V(H) domain has only three non-germline framework amino acids. This, together with its fully human nature, should minimise any potential immunogenicity of 6B1 IgG4 when used in therapy of fibrotic diseases mediated by TGFbeta2.

Oxaprozin and piroxicam, nonsteroidal antiinflammatory drugs with long half-lives: effect of protein-binding differences on steady-state pharmacokinetics

The nonsteroidal antiinflammatory drugs (NSAIDs) oxaprozin and piroxicam have long elimination half-lives (t 1/2 approximately 55 hours), permitting once-daily dose regimens. The protein-binding characteristics of these drugs, however, vary widely. This study examines the effect of these binding differences on the drugs' disposition kinetics at steady state. A total of 52 participants (26 young healthy volunteers, and 26 elderly osteoarthritic patients, 15 men and 37 women (2 of them poor metabolizers of debrisoquine [CYP2D6]) completed the two-period, two-treatment, randomized, single-dose and 21-day, once-daily multiple-dose, cross-over study. Doses of oxaprozin and piroxicam were 1,200 mg once daily and 20 mg once daily, respectively. Mean single-dose kinetic parameters of oxaprozin versus piroxicam did not differ more than +/-14% (t1/2, 53.0 versus 57.4 hours; apparent oral clearance adjusted for 70-kg body weight [Clpo], 0.139 versus 0.121 L/hr; apparent volume of distribution adjusted for 70-kg body weight [Vd/F]; 10.2 L versus 9.13 L). Protein binding was plasma-concentration dependent with oxaprozin (range, 10-400 mg/L) but not with piroxicam (range, 1-30 mg/ L). Steady-state conditions were established within 3 days with oxaprozin but took almost 12 days with piroxicam. Compared with the single-dose values, steady-state Clpo (Clpo,ss) and Vd/F of total drug increased with oxaprozin by almost 127% but remained within +/-10% with piroxicam. Post-steady-state apparent t 1/2 of the total and unbound drugs of approximately 62 hours were similarly prolonged with piroxicam but differed substantially with oxaprozin (50.6 hours [total drug] versus 23.8 hours [unbound drug]). Single dose Clpo (Clpo,sd) values of both NSAIDs were significantly correlated in the study populations. With both NSAIDs, Clpo in the two poor metabolizers of debrisoquine was within +/-20% of mean values for the population. Clinically important age- and gender-dependent decreases were not observed in the weight-adjusted, Clpo,sd or Vd/F values of the total drug for either NSAID. Clearances of the two NSAIDs were significantly correlated, suggesting that a common P450 isozyme (most likely CYP2C9, in that piroxicam is a known substrate of this isozyme) may be at least partly involved in the oxidative metabolism of these NSAIDs.

An integrated vector system for the eukaryotic expression of antibodies or their fragments after selection from phage display libraries

Phage display is now an established method to select antibody fragments specific for a wide range of diverse antigens. In particular, isolation of human monoclonal antibodies has become a reality and for most purposes bacterial expression of the selected recombinant antibody fragments is sufficient. However, there are some cases where the expression of complete human immunoglobulin in mammalian cells is, if not essential, at least desirable. For this reason we have designed and constructed a set of mammalian expression vectors which permit facile and rapid cloning of antibody genes for both transient and stable expression in mammalian cells. Immunoglobulin genes may be cloned into these expression vectors as V regions or as Fabs for expression as either complete antibodies or as Fab fragments, using restriction sites which are rare in human V genes. All the important elements in the vectors--promoter, leader sequence, constant domains and selectable markers--are flanked by unique restriction sites, allowing simple substitution of elements. The vectors have been evaluated using the variable regions from the neutralizing anti-nerve growth factor (NGF) antibody, alphaD11, and the V regions from 2E10, a scFv selected from a scFv phagemid library.

Directing phage selections towards specific epitopes

It is possible to direct selections from antibody repertoires displayed on filamentous phage towards unique epitopes on protein antigens by competing with related molecules. A phage display repertoire of human single chain Fvs (scFvs) was panned three times against foetal haemoglobin (HbF). The selection was dominated by one clone with a Kd of 10 nM but yielded at least 17 others, all of which bound HbF but crossreacted with adult haemoglobin (HbA). To direct selection towards HbF-specific epitopes, the repertoire was preincubated with HbA in solution before each panning. Crossreactive scFvs can form complexes with the soluble HbA and thereby be prevented from binding the immobilized HbF. Four clones with preferential binding to HbF emerged under these conditions. One of these (Hb-1), with a Kd of 6 microM, had exquisite specificity for HbF and could distinguish cells expressing HbF from those expressing HbA by immunocytochemistry and flow cytometry. This antibody has an affinity that is 600-fold lower than the dominant crossreactive clone, and so only emerged under conditions of 'competitive deselection'. Thus, competitive deselection is a viable means for directing selections towards useful epitopes. It permits a more effective 'search' of phage display repertoires and allows the emergence of lower affinity clones with useful specificities. These clones may be useful in themselves or may serve as leads for in vitro affinity maturation.

Generation of a panel of related human scFv antibodies with high affinities for human CEA

BACKGROUND

A human single chain Fv (scFv) specific for human carcinoembryonic antigen (CEA) has been isolated from a 2.0 x 10(9) phage display library from unimmunised human donors. The dissociation constant of the scFv has been measured by surface plasmon resonance (SPR) and found to be 7.7 x 10(-9) M, with an off-rate component of 6.2 x 10(-3) s-1. In order to investigate directly whether increased affinity leads to improved targeting of CEA-positive tumours, this scFv has been affinity matured by both targeted mutagenesis of the CDRs of heavy and light chains, and by light chain shuffling.

STUDY DESIGN

A partial randomisation scheme, biased towards amino acids commonly found as somatic mutations of germline antibody sequences, was used for directed diversification of VH and VL CDR3s. Diversification of the entire VL region was also introduced by light chain shuffling of the parental anti-CEA scFv. Selection of the mutagenised repertoires was carried out to enrich for antibodies with a reduced koff.

RESULTS

Sequencing the selected clones identified a number of amino acid changes in the VH CDR3, one of which gave a four-fold reduction in koff. Stringent selection of the light chain shuffled library resulted in several clones with a two- to three-fold reduction in koff. It has been possible to combine the selected changes from both mutagenesis approaches by using the mutagenised heavy chain and a light chain derived by shuffling to give a human scFv with a dissociation constant for human CEA of 6.0 x 10(-10) M.

CONCLUSION

A panel of human anti-CEA scFvs has been generated with differing dissociation constants for antigen, which will allow the correlation between tumour targeting efficiency in relation to binding affinity to be assessed directly. The scFv panel will be valuable in the optimisation of human antibodies for immunotherapy.

Human antibodies with sub-nanomolar affinities isolated from a large non-immunized phage display library

To generate a stable resource from which high affinity human antibodies to any given antigen can be rapidly isolated, functional V-gene segments from 43 non-immunized human donors were used to construct a repertoire of 1.4 x 10(10) single-chain Fv (scFv) fragments displayed on the surface of phage. Fragments were cloned in a phagemid vector, enabling both phage displayed and soluble scFv to be produced without subcloning. A hexahistidine tag has been incorporated to allow rapid purification of scFv by nickel chelate chromatography. This library format reduces the time needed to isolate monoclonal antibody fragments to under two weeks. All of the measured binding affinities show a Kd < 10 nM and off-rates of 10(-3) to 10(-4) s-1, properties usually associated with antibodies from a secondary immune response. The best of these scFvs, an anti-fluorescein antibody (0.3 nM) and an antibody directed against the hapten DTPA (0.8 nM), are the first antibodies with subnanomolar binding affinities to be isolated from a naive library. Antibodies to doxorubicin, which is both immunosuppressive and toxic, as well as a high affinity and high specificity antibody to the steroid hormone oestradiol have been isolated. This work shows that conventional hybridoma technology may be superseded by large phage libraries that are proving to be a stable and reliable source of specific, high affinity human monoclonal antibodies.

What do deans of medical schools and heads of departments of general practice think of preregistration rotations in general practice?

BACKGROUND

One general practice has offered preregistration rotations in general practice since 1981. Although popular with doctors who participate in the scheme, and considered a success by the associated teaching hospital, it remains the only established general practice rotation in the United Kingdom.

AIM

A study was undertaken to assess the degree of interest in preregistration rotations in general practice expressed by medical school deans and heads of departments of general practice.

METHOD

A questionnaire was sent to all 26 deans of medical schools and all 25 heads of departments of general practice of teaching hospitals in the UK that undertook clinical training.

RESULTS

A total of 24 deans (92%) and 24 heads of departments of general practice (96%) replied to the questionnaire. The scheme was thought to be of value by 58% of deans and 79% of heads of departments of general practice. Half of the teaching hospitals thought that they might consider such a rotation in the next 3-5 years. The most frequently cited problem initiating such a scheme was financial.

CONCLUSION

Given the current interest in medical teaching in the community, preregistration rotations in general practice deserve more attention.

Pharmacokinetics of high-dose intravenous ciprofloxacin in young and elderly and in male and female subjects

The effects of age and gender on the pharmacokinetics of high-dose intravenous ciprofloxacin in a healthy volunteer study were investigated. Plasma ciprofloxacin concentrations were higher in the elderly than in the young, and the pharmacokinetic parameters were not significantly different between the genders. Ciprofloxacin was well tolerated, with the majority of adverse events related to local reactions at the IV site.

Preregistration house officers in general practice

OBJECTIVES

To obtain from house officers who had rotated through general practice in their pre-registration year their views about their experience; and, separately, to compare the overall hours and type of work performed by hospital based and general practice based house officers.

DESIGN

Postal questionnaire; and self recording of working hours and duties during four consecutive weeks.

SETTING

Inner London teaching hospital and nearby general practice.

PARTICIPANTS

28 preregistration house officers in general practice, 1981-91; and 12 preregistration house officers, four each in medicine, surgery, and general practice.

RESULTS

26 out of 28 questionnaires were returned (response rate 93%). Twelve respondents were following or thinking of following a career in general practice. Twenty five respondents were satisfied with the clinical and educational aspects of the general practice rotation and would recommend the rotation, and 25 thought four months was about the right length of time in general practice. With regard to hours and type of work performed, hospital based house officers worked on average 55.5 hours a week (excluding on call), with an average of 12.5 hours (22.5%) spent in clinical activities; general practice based house officers worked about 41 hours a week, of which 24 hours (58%) were in clinical activities. House officers in hospital received less than one hour's specific teaching a week; those in general practice received nearly three hours' a week.

CONCLUSIONS

A preregistration rotation in general practice is a popular alternative to the hospital based rotation. Although this is a limited study, other medical schools should consider introducing general practice options for preregistration house officers.

Neisseria meningitidis transferrin-binding protein 1 expressed in Escherichia coli is surface exposed and binds human transferrin

A gene library of Neisseria meningitidis B15 P1.16 DNA was established in lambda Zap II and clones containing DNA encoding transferrin binding protein 1 (TBP-1) identified following hybridisation with a 63-bp DNA probe based on the codon assignment for the first 21 N-terminal amino acids of TBP-1. Sequencing of the cloned DNA demonstrated that all of the intergenic DNA (i.e. upstream of tbp-1 running through to the 3' end of the transferrin-binding protein 2 gene) and approx. 15% of tbp-1 had been cloned. The complete gene was generated using a polymerase chain reaction, with the primer for the 3' end being based on tbp-A of N. gonorrhoeae, and the approx. 2.9-kb DNA product cloned into pGem-3Z. The expressed protein (approx. 100 kDa) reacted with antiserum to an N-terminal peptide of TBP-1. In addition, the native product was surface-expressed by Escherichia coli and bound human transferrin.