Pain Reduction With Oral Methotrexate in Knee Osteoarthritis : A Randomized, Placebo-Controlled Clinical Trial.

BACKGROUND: Treatments for osteoarthritis (OA) are limited. Previous small studies suggest that the antirheumatic drug methotrexate may be a potential treatment for OA pain. OBJECTIVE: To assess symptomatic benefits of methotrexate in knee OA (KOA). DESIGN: A multicenter, randomized, double-blind, placebo-controlled trial done between 13 June 2014 and 13 October 2017. (ISRCTN77854383; EudraCT: 2013-001689-41). SETTING: 15 secondary care musculoskeletal clinics in the United Kingdom. PARTICIPANTS: A total of 207 participants with symptomatic, radiographic KOA and knee pain (severity ≥4 out of 10) on most days in the past 3 months with inadequate response to current medication were approached for inclusion. INTERVENTION: Participants were randomly assigned 1:1 to oral methotrexate once weekly (6-week escalation 10 to 25 mg) or matched placebo over 12 months and continued usual analgesia. MEASUREMENTS: The primary end point was average knee pain (numerical rating scale [NRS] 0 to 10) at 6 months, with 12-month follow-up to assess longer-term response. Secondary end points included knee stiffness and function outcomes and adverse events (AEs). RESULTS: A total of 155 participants (64% women; mean age, 60.9 years; 50% Kellgren-Lawrence grade 3 to 4) were randomly assigned to methotrexate (n = 77) or placebo (n = 78). Follow-up was 86% (n = 134; methotrexate: 66, placebo: 68) at 6 months. Mean knee pain decreased from 6.4 (SD, 1.80) at baseline to 5.1 (SD, 2.32) at 6 months in the methotrexate group and from 6.8 (SD, 1.62) to 6.2 (SD, 2.30) in the placebo group. The primary intention-to-treat analysis showed a statistically significant pain reduction of 0.79 NRS points in favor of methotrexate (95% CI, 0.08 to 1.51; P = 0.030). There were also statistically significant treatment group differences in favor of methotrexate at 6 months for Western Ontario and McMaster Universities Osteoarthritis Index stiffness (0.60 points [CI, 0.01 to 1.18]; P = 0.045) and function (5.01 points [CI, 1.29 to 8.74]; P = 0.008). Treatment adherence analysis supported a dose-response effect. Four unrelated serious AEs were reported (methotrexate: 2, placebo: 2). LIMITATION: Not permitting oral methotrexate to be changed to subcutaneous delivery for intolerance. CONCLUSION: Oral methotrexate added to usual medications demonstrated statistically significant reduction in KOA pain, stiffness, and function at 6 months. PRIMARY FUNDING SOURCE: Versus Arthritis.

Remote monitoring of patients with rheumatoid arthritis: a mixed methods evaluation across six hospitals in London, UK.

OBJECTIVES: This study evaluated the scale-up of a remote monitoring (RM) service, capturing monthly Rheumatoid Arthritis Impact of Disease scores and patient-generated text messages, for patients with rheumatoid arthritis (RA; in remission or with low disease activity) attending routine outpatient clinics across six hospitals. We explored patients and staff experiences and implementation outcomes. METHODS: A pragmatic, mixed methods approach was used, with active patient involvement throughout. We undertook a rapid review, analysed service-level data, and conducted a patient survey and patient and staff interviews, informed by the Capability, Opportunity, Motivation, Behaviour (COM-B) and Exploration, Preparation, Implementation, Sustainment (EPIS) theoretical frameworks. RESULTS: The review included 37 articles, covering themes of patient and clinician acceptability, engagement, feasibility and clinical impact. Service-level data (n = 202) showed high levels of patient engagement with the service. The patient survey (n = 155) showed patients felt the service was easy to use, had confidence in it and felt it improved access to care. Patient interview (n = 22) findings mirrored those of the survey. Motivating factors included increased responsiveness and ease of contact with clinical teams. Views from staff interviews (n = 16) were more mixed. Some implementation barriers were specific to roll-out sites. Prioritisation of staff needs was emphasised. CONCLUSION: Patients were positive about the service and engagement was high. Staff views and engagement were more mixed. Results suggest that equal levels of patient and staff engagement are required for sustainability. These findings further our understanding of the implementation challenges to scaling RM interventions for patients with RA in routine care settings.

Correction to: Persistent physical symptoms reduction intervention: a system change and evaluation in secondary care (PRINCE secondary) - a CBT-based transdiagnostic approach: study protocol for a randomised controlled trial.

An amendment to this paper has been published and can be accessed via the original article.

Persistent physical symptoms reduction intervention: a system change and evaluation in secondary care (PRINCE secondary) - a CBT-based transdiagnostic approach: study protocol for a randomised controlled trial.

BACKGROUND: Persistent physical symptoms (PPS), also known as medically unexplained symptoms (MUS), affect approximately 50% of patients in secondary care and are often associated with disability, psychological distress and increased health care costs. Cognitive behavioural therapy (CBT) has demonstrated both short- and long-term efficacy with small to medium effect sizes for PPS, with larger treatment effects for specific PPS syndromes, including non-cardiac chest pain, irritable bowel syndrome (IBS) and chronic fatigue syndrome (CFS). Research indicates that PPS conditions share similar cognitive and behavioural responses to symptoms, such as avoidance and unhelpful beliefs. This suggests that a transdiagnostic approach may be beneficial for patients with PPS. METHODS: A randomised controlled trial (RCT) will be conducted to evaluate the efficacy and cost-effectiveness of a transdiagnostic CBT-based intervention for PPS. 322 participants with PPS will be recruited from secondary care clinics. Participants stratified by clinic and disability level will be randomised to CBT plus standard medical care (SMC) versus SMC alone. The intervention consists of 8 CBT sessions delivered by a qualified therapist over a period of 20 weeks. Outcomes will be assessed at 9, 20, 40- and 52-weeks post randomisation. Efficacy will be assessed by examining the difference between arms in the primary outcome Work and Social Adjustment Scale (WSAS) at 52 weeks after randomisation. Secondary outcomes will include mood, symptom severity and clinical global impression at 9, 20, 40 and 52 weeks. Cost-effectiveness will be evaluated by combining measures of health service use, informal care, loss of working hours and financial benefits at 52 weeks. DISCUSSION: This trial will provide a powered evaluation of the efficacy and cost-effectiveness of a transdiagnostic CBT approach versus SMC for patients with PPS. It will also provide valuable information about potential healthcare pathways for patients with PPS within the National Health Service (NHS). TRIAL REGISTRATION: ClinicalTrials.gov NCT02426788. Registered 27 April 2015. Overall trial status: Ongoing; Recruitment status: No longer recruiting.

Hydroxychloroquine Effectiveness in Reducing Symptoms of Hand Osteoarthritis: A Randomized Trial.

Background: Synovitis is believed to play a role in producing symptoms in persons with hand osteoarthritis, but data on slow-acting anti-inflammatory treatments are sparse. Objective: To determine the effectiveness of hydroxychloroquine versus placebo as an analgesic treatment of hand osteoarthritis. Design: Randomized, double-blind, placebo-controlled clinical trial with 12-month follow-up. (ISRCTN registry number: ISRCTN91859104). Setting: 13 primary and secondary care centers in England. Participants: Of 316 patients screened, 248 participants (82% women; mean age, 62.7 years) with symptomatic (pain ≥4 on a 0- to 10-point visual analogue scale) and radiographic hand osteoarthritis were randomly assigned and 210 (84.7%) completed the 6-month primary end point. Intervention: Hydroxychloroquine (200 to 400 mg) or placebo (1:1) for 12 months with ongoing usual care. Measurements: The primary end point was average hand pain during the previous 2 weeks (on a 0- to 10-point numerical rating scale [NRS]) at 6 months. Secondary end points included self-reported pain and function, grip strength, quality of life, radiographic structural change, and adverse events. Baseline ultrasonography was done. Results: At 6 months, mean hand pain was 5.49 points in the placebo group and 5.66 points in the hydroxychloroquine group, with a treatment difference of -0.16 point (95% CI, -0.73 to 0.40 point) (P = 0.57). Results were robust to adjustments for adherence, missing data, and use of rescue medication. No significant treatment differences existed at 3, 6, or 12 months for any secondary outcomes. The percentage of participants with at least 1 joint with synovitis was 94% (134 of 143) on grayscale ultrasonography and 59% on power Doppler. Baseline structural damage or synovitis did not affect treatment response. Fifteen serious adverse events were reported (7 in the hydroxychloroquine group [3 defined as possibly related] and 8 in the placebo group). Limitation: Hydroxychloroquine dosage restrictions may have reduced efficacy. Conclusion: Hydroxychloroquine was no more effective than placebo for pain relief in patients with moderate to severe hand pain and radiographic osteoarthritis. Primary Funding Source: Arthritis Research UK.

Safety and patient response as indicated by biomarker changes to binding immunoglobulin protein in the phase I/IIA RAGULA clinical trial in rheumatoid arthritis.

OBJECTIVES: Binding immunoglobulin protein (BiP) is a human endoplasmic reticulum-resident stress protein. In pre-clinical studies it has anti-inflammatory properties due to the induction of regulatory cells. This randomized placebo-controlled, dose ascending double blind phase I/IIA trial of BiP in patients with active RA, who had failed accepted therapies, had the primary objective of safety. Potential efficacy was measured by DAS28-ESR and changes in biomarkers. METHODS: Twenty-four patients with active RA who had failed one or more DMARDs were sequentially assigned to three groups each of eight patients randomly allocated to receive placebo (two patients) or BiP (six patients), 1, 5 or 15 mg. Patients received a single i.v. infusion over 1 h and were observed as inpatients overnight. A 12-week follow-up for clinical, rheumatological and laboratory assessments for safety, efficacy (DAS28-ESR) and biomarker analysis was performed. RESULTS: No infusion reactions or serious adverse drug reactions were noted. Adverse events were evenly distributed between placebo and BiP groups with no BiP-related toxicities. Haematological, renal and metabolic parameters showed no drug-related toxicities. Remission was only achieved by patients in the 5 and 15 mg groups, and not patients who received placebo or 1 mg BiP. Good DAS28-ESR responses were achieved in all treatment groups. The BiP responding patients showed significantly lower serum concentrations of CRP, 2 weeks post-infusion compared with pre-infusion levels, and of VEGF and IL-8 from the placebo group. CONCLUSION: BiP (⩽15 mg) is safe in patients with active RA. Some patients had clinical and biological improvements in RA activity. BiP merits further study. TRIAL REGISTRATION: ISRCTN registry, http://isrctn.com, ISRCTN22288225 and EudraCT, https://eudract.ema.europa.eu, 2011-005831-19.

Rheumatoid arthritis patients with fibromyalgic clinical features have significantly less synovitis as defined by power Doppler ultrasound.

BACKGROUND: In patients with rheumatoid arthritis (RA) clinical measures of disease activity may not reliably discriminate between patients with active inflammatory disease and those with concomitant fibromyalgia (FM). Recent work has shown RA patients with a 28 tender joint count (TJC) minus swollen joint count (SJC) of 7 or more (joint count criteria) are more likely to meet classification criteria for FM. This study aimed to determine whether RA patients meeting clinical criteria for FM had lower levels of joint inflammation as determined by ultrasound (US). METHODS: RA patients with DAS28 > 2.6 were recruited. Patients underwent clinical assessment including ultrasound examination of the hands and wrists with quantification of grey scale (GS) and power Doppler (PD) synovitis. Patients completed questionnaires to assess pain, fatigue, disability and psychological comorbidity. RESULTS: Patients meeting either of the FM criteria had higher scores for disease activity, depression, disability and fatigue. Those meeting both the joint count and classification FM criteria had significantly lower levels of GS and PD inflammation on US. CONCLUSIONS: RA patients with concomitant FM, as determined by widespread soft tissue tenderness but fewer clinically inflamed joints, have higher disease activity scores but may have lower levels of synovial inflammation on US. This has implications for the identification and management of these patients who may not respond to conventional therapy and hence be more suitable for alternative approaches to treatment.

Pain sensitisation and joint inflammation in patients with active rheumatoid arthritis.

INTRODUCTION: Despite better therapies and strategies, many people with rheumatoid arthritis (RA) have persistent pain, often from abnormal pain processing, now termed nociplastic pain. However, RA patients with fibromyalgia (FM), a central nociplastic pain syndrome, also have power doppler ultrasound (PDUS+) joint inflammation. To understand the complex causes of pain, we performed clinical examination and patient-reported outcome measures (PROMs) plus comprehensive PDUS evaluation not previously combined. METHODS: In a cross-sectional study of sequential RA patients with at least moderate DAS28 erythrocyte sedimentation rate disease activity, we assessed 66/68 joints for swelling and tenderness, respectively, FM American College of Rheumatology 2010 diagnostic criteria, completed PROMs for function, quality of life and mood, alongside PDUS examination of 44 joints. Statistical analysis included logistic regression modelling and regularised (lasso) logistic regression methods. RESULTS: From 158 patients, 72 (46%) patients met FM criteria, with significantly worse tender joint counts and PROMs, but no differences in PDUS compared with the non-FM group. Categorising patients by PDUS+ joint presence and/or FM criteria, we identified four distinct groups: 43 (27.2%) patients with -FM-PD, 43 (27.2%) with -FM+PD, 42 (26.6%) with +FM-PD and 30 (19%) with +FM+PD. Both FM+ groups had worse PROMs for fatigue, mood and pain, compared with the FM- groups. We were unable to develop algorithms to identify different groups. CONCLUSION: The unexpected group -FM-PD group may have peripheral nociplastic pain, not commonly recognised in rheumatology. Only 46% of patients demonstrated PDUS+ inflammation. However clinical examination and PROMs did not reliably differentiate groups, emphasising PDUS remains an important tool.

The Clinical Impact of Electronic Patient-Reported Outcome Measures in the Remote Monitoring of Inflammatory Arthritis: A Systematic Review and Meta-analysis.

OBJECTIVE: The inflammatory arthritides (IAs) make up a significant proportion of conditions followed up in rheumatology clinics. These patients require regular monitoring, but this is increasingly difficult with rising patient numbers and demand on clinics. Our objective is to evaluate the clinical impact of electronic patient-reported outcome measures (ePROMs) as a digital remote-monitoring intervention on disease activity, treatment decisions, and health care resource use in patients with IA. METHODS: Five databases (MEDLINE, Embase, PubMed, Cochrane Library, and Web of Science) were searched, with randomized controlled trials and (nonrandomized) controlled clinical trials included, and meta-analysis and forest plots conducted for each outcome. Risk of bias was assessed using the Risk of Bias-2 tool and Risk of Bias in Nonrandomized Studies of Interventions. RESULTS: Eight studies were included with a total of 4,473 patients, with seven studies assessing patients with rheumatoid arthritis. Compared with control, the disease activity in the ePROM group was lower (standardized mean difference [SMD] -0.15; 95% confidence interval [CI] -0.27 to -0.03) and rates of remission/low disease activity were higher (odds ratio1.65; 95% CI 1.02-2.68), but five of eight studies provided additional combined interventions (e.g., disease education). Fewer face to face visits were needed in the remote ePROM group (SMD -0.93; 95% CI -2.14-0.28). CONCLUSION: Most studies were at high risk of bias with significant heterogeneity in design, but our results suggest there is an advantage in using ePROM monitoring in patients with IAs, with the potential for reduction in health care resource use without detrimental impact in disease outcomes.

Development of a novel recombinant biotherapeutic with applications in targeted therapy of human arthritis.

OBJECTIVE: To isolate recombinant antibodies with specificity for human arthritic synovium and to develop targeting reagents with joint-specific delivery capacity for therapeutic and/or diagnostic applications. METHODS: In vivo single-chain Fv (scFv) antibody phage display screening using a human synovial xenograft model was used to isolate antibodies specific to the microvasculature of human arthritic synovium. Single-chain Fv antibody tissue-specific reactivity was assessed by immunostaining of synovial tissues from normal controls and from patients with rheumatoid arthritis and osteoarthritis, normal human tissue arrays, and tissues from other patients with inflammatory diseases displaying neovasculogenesis. In vivo scFv antibody tissue-specific targeting capacity was examined in the human synovial xenograft model using both (125)I-labeled and biotinylated antibody. RESULTS: We isolated a novel recombinant human antibody, scFv A7, with specificity for the microvasculature of human arthritic synovium. We showed that in vivo, this antibody could efficiently target human synovial microvasculature in SCID mice transplanted with human arthritic synovial xenografts. Our results demonstrated that scFv A7 antibody had no reactivity with the microvasculature or with other cellular components found in a comprehensive range of normal human tissues including normal human synovium. Further, we showed that the reactivity of the scFv A7 antibody was not a common feature of neovasculogenesis associated with chronic inflammatory conditions. CONCLUSION: Here we report for the first time the identification of an scFv antibody, A7, that specifically recognizes an epitope expressed in the microvasculature of human arthritic synovium and that has the potential to be developed as a joint-specific pharmaceutical.

Delivering outpatient virtual clinics during the COVID-19 pandemic: early evaluation of clinicians' experiences.

BACKGROUND: The COVID-19 pandemic has put health systems across the world under significant pressure. In March 2020, a national directive was issued by the National Health Service (NHS) England instructing trusts to scale back face-to-face outpatient appointments, and rapidly implement virtual clinics. METHODS: A multidisciplinary team of change managers, analysts and clinicians were assembled to evaluate initial implementation of virtual clinics at Guy's and St Thomas' NHS Foundation Trust. In-depth interviews were conducted with clinicians who have delivered virtual clinics during the pandemic. An inductive thematic approach was used to analyse clinicians' early experiences and identify enablers for longer term sustainability. RESULTS: Ninety-five clinicians from specialist services across the trust were interviewed between April and May 2020 to reflect on their experiences of delivering virtual clinics during Wave I COVID-19. Key reflections include the perceived benefits of virtual consultations to patients and clinicians; the limitations of virtual consultations compared with face-to-face consultations; and the key enablers that would optimise and sustain the delivery of virtual pathways longer term. CONCLUSIONS: In response to the pandemic, outpatient services across the trust were rapidly redesigned and virtual clinics implemented. As a result, services have been able to sustain some level of service delivery. However, clinicians have identified challenges in delivering this model of care and highlighted enablers needed to sustaining the delivery of virtual clinics longer term, such as patient access to diagnostic tests and investigations closer to home.

A novel model for the pre-clinical imaging of inflamed human synovial vasculature.

OBJECTIVE: The purpose of this study was to explore the development of a pre-clinical nuclear imaging model as a tool for testing novel radiopharmaceutical agents for imaging and/or delivery systems to human tissues. Here we report for the first time the imaging of human synovial tissue transplanted into SCID mice using a radiolabelled anti-E-selectin antibody and NanoSPECT/CT technology. METHODS: Human synovium was transplanted into SCID mice. Two to three weeks post-transplantation tissue vasculature was stimulated with TNF-alpha by intra-graft injection 5 h prior to intravenous injection of (111)In-labelled anti-E-selectin or isotype control antibody. At 1, 4, 24 and 48 h animals were imaged and transplant activity quantified. RESULTS: Activity was detectable in the grafts at all time points, with clear delineation of the transplants in the reconstructed images. A significant difference in graft radioactivity was observed at 4 and 24 h with a significantly higher uptake (P < 0.05) of (111)In-anti-E-selectin compared with isotype control antibody. CONCLUSIONS: This article highlights NanoSPECT/CT imaging in the SCID mouse chimeric model as a powerful tool for the pre-clinical development of radiopharmaceutical and delivery agents targeting human synovial tissue in vivo.

Real world long-term impact of intensive treatment on disease activity, disability and health-related quality of life in rheumatoid arthritis.

BACKGROUND: The emphasis on treating rheumatoid arthritis (RA) intensively reduces disease activity but its impact in routine care is uncertain. We evaluated temporal changes in disease activities and outcomes in a 10-year prospective observational cohort study of patients in routine care at one unit. METHODS: The Guy's and St Thomas' RA cohort was established in 2005. It involved most RA patients managed in this hospital. Clinical diagnoses of RA were made by rheumatologists. Patients were seen regularly in routine care. Each visit included measurement of disease activity scores for 28 joints (DAS28), health assessment questionnaire scores (HAQ) and EuroQol scores. Patients received intensive treatments targeting DAS28 remission. RESULTS: In 1693 RA patients mean DAS28 scores fell from 2005 to 15 by 11% from 4.08 (95% CI: 3.91, 4.25) in 2005 to 3.64 (3.34, 3.78); these falls were highly significant (p < 0.001). DAS28 components: swollen joint counts fell by 32% and ESR by 24%; in contrast tender joint counts and patient global assessments showed minimal or no reductions. The reduction in DAS28 scores was predominantly between 2005 and 2010, with no falls from 2011 onwards. Associated with falls in mean DAS28s, patients achieving remission increased (18% in 2005; 27% in 2015) and the number with active disease (DAS28 > 5.1) decreased (25% in 2005; 16% in 2015). In 752 patients seen at least annually for 3 years, persisting remission (68 patients) and intermittent remission (376 patients) were associated with less disability and better health related quality of life. Over time biologic use increased, but they were used infrequently in patients in persistent remission. CONCLUSIONS: Over 10 years an intensive management strategy in a routine practice setting increased combination DMARD and biologic use: disease activity levels declined; this association is in keeping with a causal relationship. Patients who achieved remission, even transiently, had better functional outcomes than patients never achieving remission.

Flares in Rheumatoid Arthritis Patients with Low Disease Activity: Predictability and Association with Worse Clinical Outcomes.

OBJECTIVE: To investigate predictors of flare in rheumatoid arthritis (RA) patients with low disease activity (LDA) and to evaluate the effect of flare on 12-month clinical outcomes. METHODS: Patients with RA who were taking disease-modifying antirheumatic drugs and had a stable 28-joint count Disease Activity Score (DAS28) < 3.2 were eligible for inclusion. At baseline and every 3 months, clinical (DAS28), functional [Health Assessment Questionnaire-Disability Index (HAQ-DI), EQ-5D, Functional Assessment of Chronic Illness Therapy Fatigue scale (FACIT-F), Medical Outcomes Study Short Form-36 (SF-36)], serum biomarkers [multibiomarker disease activity (MBDA) score, calprotectin, CXCL10], and imaging data were collected. Flare was defined as an increase in DAS28 compared with baseline of > 1.2, or > 0.6 if concurrent DAS28 ≥ 3.2. Cox regression analyses were used to identify baseline predictors of flare. Biomarkers were cross-sectionally correlated at time of flare. Linear regressions were performed to compare clinical outcomes after 1 year. RESULTS: Of 152 patients, 46 (30%) experienced a flare. Functional disability at baseline was associated with flare: HAQ-DI had an unadjusted HR 1.82 (95% CI 1.20-2.72) and EQ-5D had HR 0.20 (95% CI 0.07-0.57). In multivariate analyses, only HAQ-DI remained a significant independent predictor of flare (HR 1.76, 95% CI 1.05-2.93). At time of flare, DAS28 and its components significantly correlated with MBDA and calprotectin, but correlation coefficients were low at 0.52 and 0.49, respectively. Two-thirds of flares were not associated with a rise in biomarkers. Patients who flared had significantly worse outcomes at 12 months (HAQ-DI, EQ-5D, FACIT-F, SF-36, and radiographic progression). CONCLUSION: Flares occur frequently in RA patients with LDA and are associated with worse disease activity, quality of life, and radiographic progression. Higher baseline HAQ-DI was modestly predictive of flare, while biomarker correlation at the time of flare suggests a noninflammatory component in a majority of events.

In vivo phage display selection in the human/SCID mouse chimera model for defining synovial specific determinants.

Phage display has represented a phenomenal technological advance of the last two decades. This technique is a very effective way of producing large numbers (up to 10(12)) of diverse peptides and proteins (including antibodies), presented as fusion proteins on the viral capsid, that can be used for isolating specific molecules for therapeutic targeting. The increasing realization of the importance of the vascular endothelium in chronic inflammation as well as in neoplastic growth/spreading has prompted the targeting of blood vessels using phage display. This technique has been very successful in vivo in animals in selecting tissue specific vascular determinants. However, one disadvantage of using "pure" animal models is that the ligands obtained in this way are, by definition, specific for the targeted animal and might not bind to the human homologues. For this reason we have developed a novel approach using in vivo phage display selection against human tissues transplanted into SCID animals. In particular, we have focused on the transplantation of human synovium, although we have also successfully grafted skin, lymphoid, and fetal gut into these animals. The strength of this model is that the human graft blood vessels form functional anastomoses with mouse subdermal vessels that allow the target of lumenally expressed human molecules via the mouse circulation. Here we first describe the technical procedure for the in vivo selection of synovial homing phage using a commercially available peptide phage library in SCID mice transplanted with human synovium. This is followed by the description of the quantification and isolation of putative synovial specific peptide sequences. Finally, we describe the methodology used to confirm peptide-binding specificity including a competitive inhibition assay with synthetic peptide and the parent phage. The information provided should enable the reader to apply this technology in an in vivo setting to target human tissues in order to identify novel organ specific determinants as well as to develop tissue specific drug delivery systems.