Satisfaction with radiotherapy care among cancer patients treated in Germany-secondary analysis of a large multicenter study

PURPOSE

Patient satisfaction with healthcare has been linked to clinical outcomes and regulatory agencies demand its regular assessment. Therefore, we aimed to investigate patient satisfaction with radiotherapy care and its determinants.

METHODS

This is a secondary analysis of a multicenter prospective cross-sectional study. Eligible cancer patients anonymously completed questionnaires at the end of a course of radiotherapy. The outcome variable was overall patient satisfaction with radiotherapy care measured with a 10-point Likert scaled single-item. Given patient satisfaction was defined for patients scoring ≥ 8 points. Determinants of given patient satisfaction were assessed by univariable and multivariable analyses. A p-value < 0.05 was considered statistically significant.

RESULTS

Out of 2341 eligible patients, 1075 participated (participation rate 46%). Data on patient satisfaction was provided by 1054 patients. There was a right-skewed distribution towards more patient satisfaction (mean = 8.8; SD = 1.68). Given patient satisfaction was reported by 85% (899/1054) of the patients. Univariable analyses revealed significant associations of lower patient satisfaction with tumor entity (rectal cancer), concomitant chemotherapy, inpatient care, treating center, lower income, higher costs, and lower quality of life. Rectal cancer as tumor entity, treating center, and higher quality of life remained significant determinants of patient satisfaction in a multivariable logistic regression.

CONCLUSION

Overall patient satisfaction with radiotherapy care was high across 11 centers in Germany. Determinants of patient satisfaction were tumor entity, treating center, and quality of life. Although these data are exploratory, they may inform other centers and future efforts to maintain high levels of patient satisfaction with radiotherapy care.

Patient-Relevant Costs for Organ Preservation versus Radical Resection in Locally Advanced Rectal Cancer

Total neoadjuvant therapy (TNT) is an evolving treatment schedule for locally advanced rectal cancer (LARC), allowing for organ preservation in a relevant number of patients in the case of complete response. Patients who undergo this so-called "watch and wait" approach are likely to benefit regarding their quality of life (QoL), especially if definitive ostomy could be avoided. In this work, we performed the first cost-effectiveness analysis from the patient perspective to compare costs for TNT with radical resection after neoadjuvant chemoradiation (CRT) in the German health care system. Individual costs for patients insured with a statutory health insurance were calculated with a Markov microsimulation. A subgroup analysis from the prospective "FinTox" trial was used to calibrate the model's parameters. We found that TNT was less expensive (-1540 EUR) and simultaneously resulted in a better QoL (+0.64 QALYs) during treatment and 5-year follow-up. The average cost for patients under TNT was 4711 EUR per year, which was equivalent to 3.2% of the net household income. CRT followed by resection resulted in higher overall costs for ostomy care, medication and greater loss of earnings. Overall, TNT appeared to be more efficacious and cost-effective from a patient's point of view in the German health care system.

Pelvic Irradiation for Node-Positive Prostate Cancer After Prostatectomy: Long-Term Results of the Prospective PLATIN-4 and PLATIN-5 Trials

PURPOSE

After radical prostatectomy (RP), adjuvant or salvage radiation treatment in node-positive prostate cancer is offered to prevent systemic disease. Prospective long-term survival and toxicity data on patients with radiation for nodal disease are still scarce. This study evaluates safety and feasibility of salvage radiation therapy to the pelvic lymph nodes in node-positive prostate cancer after RP.

METHODS AND MATERIALS

Between 2009 and 2018, 78 patients with lymph node recurrence after RP (PLATIN-4 trial) or after RP and prostate bed radiation therapy (PLATIN-5 trial) were treated with salvage pelvic lymph node radiation therapy with boost to the involved nodes as field abutment (PLATIN-5) and boost to the prostate bed (PLATIN-4). Androgen deprivation therapy was started 2 months before radiation and recommended for 24 months. The primary endpoint was safety and feasibility of the intensity modulated radiation therapy-image guided radiation therapy technique based on the rate of treatment discontinuations and incidence of Common Terminology Criteria for Adverse Events grade 3+ toxicity. Secondary endpoints were progression-free survival and overall survival.

RESULTS

No treatment discontinuations were reported in either trial. Median overall survival was not reached in PLATIN-4 and was 117 months in PLATIN-5. Median progression-free survival was 66 months in PLATIN-4 and 39 months in PLATIN-5. Late grade 3+ genitourinary and gastrointestinal toxicities were observed in 4% of patients at 24 months of follow-up.

CONCLUSIONS

Salvage radiation therapy to the prostate bed and pelvic lymphatic drainage combined with long-term androgen deprivation therapy is a curative treatment option for patients with node-positive prostate cancer after RP, with excellent in-field disease control. Pelvic lymph node radiation therapy as field abutment after prostate bed radiation therapy is feasible with long-term survival and no high-grade toxicity.

Whole-pelvic irradiation with boost to involved nodes and prostate in node-positive prostate cancer-long-term data from the prospective PLATIN-2 trial

PURPOSE

Node-positive prostate cancer is a potentially curable disease. Definitive radiotherapy to the prostate and lymphatic drainage is an effective treatment option but prospective long-term outcome data are scarce. Thus, the current study aimed to evaluate the toxicity and efficacy of definitive radiation therapy for men with prostate cancer and nodal metastases using modern irradiation techniques.

METHODS

A total of 40 treatment-naïve men with node-positive prostate cancer were allocated to the trial. All patients received definitive radiation therapy at two German university hospitals between 2009 and 2018. Radiation was delivered as intensity-modulated radiation therapy (IMRT) with 51 Gy to the lymphatic drainage with simultaneous integrated boost (SIB) up to 61.2 Gy to involved nodes and 76.5 Gy to the prostate in 34 fractions. Feasibility and safety, overall and progression-free survival, toxicity, and quality of life measurements were analyzed.

RESULTS

During a median follow-up of 79 months, median overall survival was 107 months and progression-free survival was 78 months. Based on imaging follow-up, no infield relapse was reported during the first 24 months of follow-up. There were 3 (8%) potentially treatment-related grade 3 toxicities. Common iliac node involvement was associated with a higher risk of progression (HR 15.8; 95% CI 2.1-119.8; p = 0.007).

CONCLUSION

Definitive radiation to the lymphatic drainage with SIB to the involved nodes and prostate is a safe and effective treatment approach for patients with treatment-naïve, node-positive prostate cancer with excellent infield tumor control rates and tolerable toxicity. Location rather than number of involved nodes is a major risk factor for progression.

Dosimetric benefit of online treatment plan adaptation in stereotactic ultrahypofractionated MR-guided radiotherapy for localized prostate cancer

Background

Apart from superior soft tissue contrast, MR-guided stereotactic body radiation therapy (SBRT) offers the chance for daily online plan adaptation. This study reports on the comparison of dose parameters before and after online plan adaptation in MR-guided SBRT of localized prostate cancer.

Materials and methods

32 consecutive patients treated with ultrahypofractionated SBRT for localized prostate cancer within the prospective SMILE trial underwent a planning process for MR-guided radiotherapy with 37.5 Gy applied in 5 fractions. A base plan, derived from MRI simulation at an MRIdian Linac, was registered to daily MRI scans (predicted plan). Following target and OAR recontouring, the plan was reoptimized based on the daily anatomy (adapted plan). CTV and PTV coverage and doses at OAR were compared between predicted and adapted plans using linear mixed regression models.

Results

In 152 out of 160 fractions (95%), an adapted radiation plan was delivered. Mean CTV and PTV coverage increased by 1.4% and 4.5% after adaptation. 18% vs. 95% of the plans had a PTV coverage ≥95% before and after online adaptation, respectively. 78% vs. 100% of the plans had a CTV coverage ≥98% before and after online adaptation, respectively. The D0.2cc for both bladder and rectum were <38.5 Gy in 93% vs. 100% before and after online adaptation. The constraint at the urethra with a dose of <37.5 Gy was achieved in 59% vs. 93% before and after online adaptation.

Conclusion

Online adaptive plan adaptation improves target volume coverage and reduces doses to OAR in MR-guided SBRT of localized prostate cancer. Online plan adaptation could potentially further reduce acute and long-term side effects and improve local failure rates in MR-guided SBRT of localized prostate cancer.

Potential of ChatGPT and GPT-4 for Data Mining of Free-Text CT Reports on Lung Cancer

Background The latest large language models (LLMs) solve unseen problems via user-defined text prompts without the need for retraining, offering potentially more efficient information extraction from free-text medical records than manual annotation. Purpose To compare the performance of the LLMs ChatGPT and GPT-4 in data mining and labeling oncologic phenotypes from free-text CT reports on lung cancer by using user-defined prompts. Materials and Methods This retrospective study included patients who underwent lung cancer follow-up CT between September 2021 and March 2023. A subset of 25 reports was reserved for prompt engineering to instruct the LLMs in extracting lesion diameters, labeling metastatic disease, and assessing oncologic progression. This output was fed into a rule-based natural language processing pipeline to match ground truth annotations from four radiologists and derive performance metrics. The oncologic reasoning of LLMs was rated on a five-point Likert scale for factual correctness and accuracy. The occurrence of confabulations was recorded. Statistical analyses included Wilcoxon signed rank and McNemar tests. Results On 424 CT reports from 424 patients (mean age, 65 years ± 11 [SD]; 265 male), GPT-4 outperformed ChatGPT in extracting lesion parameters (98.6% vs 84.0%, P < .001), resulting in 96% correctly mined reports (vs 67% for ChatGPT, P < .001). GPT-4 achieved higher accuracy in identification of metastatic disease (98.1% [95% CI: 97.7, 98.5] vs 90.3% [95% CI: 89.4, 91.0]) and higher performance in generating correct labels for oncologic progression (F1 score, 0.96 [95% CI: 0.94, 0.98] vs 0.91 [95% CI: 0.89, 0.94]) (both P < .001). In oncologic reasoning, GPT-4 had higher Likert scale scores for factual correctness (4.3 vs 3.9) and accuracy (4.4 vs 3.3), with a lower rate of confabulation (1.7% vs 13.7%) than ChatGPT (all P < .001). Conclusion When using user-defined prompts, GPT-4 outperformed ChatGPT in extracting oncologic phenotypes from free-text CT reports on lung cancer and demonstrated better oncologic reasoning with fewer confabulations. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Hafezi-Nejad and Trivedi in this issue.

Comorbidity in limited disease small-cell lung cancer: Age-adjusted Charlson comorbidity index and its association with overall survival following chemoradiotherapy

Background

Combined, platinum-based thoracic chemoradiotherapy (TCR) is the current state-of-the-art treatment for patients with limited disease (LD) small-cell lung cancer (SCLC). There is only limited data available regarding the effect of comorbidities on survival following TRC. The purpose of this study is to assess the age-adjusted Charlson comorbidity index (ACCI) as a predictor of overall survival in LD-SCLC patients undergoing TCR.

Patients and methods

We retrospectively analyzed 367 SCLC patients diagnosed with LD-SCLC who received TCR between 2003 and 2017. We evaluated the ACCI (n = 348) as a predictor of overall survival (OS). In this cohort, 322 patients (88%) received platinum-based TCR (either cisplatin or carboplatin), and 37 (10%) patients received vincristine based TCR. Median radiation dose was 60 Gy (range 24-66 Gy). Additionally, 83% of patients (n = 303) received prophylactic cranial irradiation (PCI, 30 Gy in 2 Gy fractions). Kaplan-Meier survival analysis was performed for OS. For comparison of survival curves, Log-rank (Mantel-Cox) test was used. Univariate and multivariate Cox proportional-hazards ratios (HRs) were used to assess the influence of cofactors on OS.

Results

Patients with an ACCI > 6 had a significantly shorter OS compared with patients with an ACCI ≤ 6 (median 11 vs. 20 months; p = 0.005). Univariate analysis for OS revealed a statistically significant effect for ACCI > 6 (HR 1.7; 95% CI 1.2-2.4; p = 0.003), PCI (HR 0.5; 95% CI 0.3-0.7; p < 0.001), and Karnofsky performance status ≤ 70% (KPS) (HR 1.4; 95% CI 1.1-1.90; p = 0.015). In multivariate analysis, OS was significantly associated with PCI (HR 0.6; 95% CI 0.4-0.9; p = 0.022) and ACCI > 6 (HR 1.5; 95% CI 1.0-2.1; p = 0.049).

Conclusion

Comorbidity is significantly associated with survival in patients with LD-SCLC undergoing TCR. The ACCI may be a valuable tool to identify patients with a shorter survival and thus might be used for risk stratification and oncological decision making.

Psychosocial distress in cancer patients undergoing radiotherapy: a prospective national cohort of 1042 patients in Germany

PURPOSE

Psychosocial distress is common among cancer patients in general, but those undergoing radiotherapy may face specific challenges. Therefore, we investigated the prevalence and risk factors for distress in a large national cohort.

METHODS

We performed a secondary analysis of a multicenter prospective cross-sectional study which surveyed cancer patients at the end of a course of radiotherapy using a patient-reported questionnaire. Distress was measured with the distress thermometer (DT), using a cut-off of ≥ 5 points for clinically significant distress. Univariate analyses and multivariate multiple regression were used to assess associations of distress with patient characteristics. A two-sided p-value < 0.05 was considered statistically significant.

RESULTS

Out of 2341 potentially eligible patients, 1075 participated in the study, of which 1042 completed the DT. The median age was 65 years and 49% (511/1042) of patients were female. The mean DT score was 5.2 (SD = 2.6). Clinically significant distress was reported by 63% (766/1042) of patients. Of the patient characteristics that were significantly associated with distress in the univariate analysis, a lower level of education, a higher degree of income loss, lower global quality of life, and a longer duration of radiotherapy in days remained significantly associated with higher distress in the multivariate analysis. Yet effect sizes of these associations were small.

CONCLUSION

Nearly two in three cancer patients undergoing radiotherapy reported clinically significant distress in a large multicenter cohort. While screening and interventions to reduce distress should be maintained and promoted, the identified risk factors may help to raise awareness in clinical practice.

TRIAL REGISTRY IDENTIFIER

DRKS: German Clinical Trial Registry identifier: DRKS00028784.

Detecting and Locating the Site of Local Relapse Using 18F-PSMA-1007 Imaging After Primary Treatment of 135 Prostate Cancer Patients-Potential Impact on PSMA-Guided Radiation Therapy

PURPOSE

Due to limited imaging options, the visualization of a local relapse of prostate cancer used to pose a considerable challenge. However, since the integration of ¹⁸F-PSMA-1007-PET/CT into the clinic, a relapsed tumor can now easily be detected by hybrid imaging. The present study aimed to evaluate and map the allocate relapse in a large cohort of prostate cancer patients focusing on individual patient management conclusions for radiation therapy.

PROCEDURES

The current study included 135 men with prostate cancer after primary treatment who underwent ¹⁸F-PSMA-1007-PET/CT due to biochemical relapse detecting a local relapse. Imaging data were reassessed and analyzed with regard to relapse locations. For the correlation of tumor foci with clinical data, we used binary logistic regression models as well as the Kruskal-Wallis test and Mann-Whitney test.

RESULTS

In total, 69.6% of all patients (mean age: 65 years) underwent prostatectomy while 30.4% underwent radiation therapy. PET imaging detected most frequently a unifocal relapse (72.6%). There was a statistically significantly higher rate of ipsilateral cases among the relapsed tumors. Comparing both treatment approaches, tumors relapsed most commonly within the posterior region after surgery and transition/peripheral zone after radiation therapy, respectively.

CONCLUSIONS

The present study confirms that ¹⁸F-PSMA-1007-PET/CT is highly suitable for the localization and allocation of a local relapse in patients with prostate cancer. The data enable further optimizing dose prescriptions and target volume delineations of radiation therapy in the future.

Financial toxicity in cancer patients undergoing radiotherapy in a universal health care system - a prospective multicenter study of 1075 patients

PURPOSE

To establish and confirm prevalence as well as risk factors of financial toxicity in a large national cohort of cancer patients undergoing radiotherapy in a universal health care system.

METHODS

We conducted a prospective cross-sectional study offering a patient-reported questionnaire to all eligible cancer patients treated with radiotherapy in 11 centers in Germany during 60 consecutive days. The four-point subjective financial distress question of the EORTC QLQ-C30 was used as a surrogate for financial toxicity. Confirmatory hypothesis testing evaluated the primary study outcomes: overall prevalence of financial toxicity and its association with predefined risk factors. P-values <.05 were considered statistically significant.

RESULTS

Of 2341 eligible patients, 1075 (46%) participated. The prevalence of subjective financial distress (=any grade higher than not present) was 41% (438/1075) exceeding the hypothesized range of 26.04-36.31%. Subjective financial distress was felt "A little" by 26% (280/1075), "Quite a bit" by 11% (113/1075) and "Very much" by 4% (45/1075) of the patients. Lower household income, lower global health status/ quality of life, higher direct costs and higher loss of income significantly predicted higher subjective financial distress per ordinal regression and confirmed these risk factors. Higher psychosocial distress and lower patient satisfaction were significantly associated with higher subjective financial distress in an exploratory ordinal regression model.

CONCLUSION

The overall prevalence of financial toxicity was higher than anticipated, although reported at low or moderate degrees by most affected patients. As we confirmed risk factors associated with financial toxicity, patients at risk should be addressed early for potential support.

[Imaging of oligometastatic disease in selected urologic cancers]

BACKGROUND

Local treatment of the primary or metastatic sites in urologic malignancies is promising when compared to systemic therapy alone, leading to the definition of a potentially curative oligometastatic state.

OBJECTIVES

Comparison of imaging modalities regarding local and metastatic tumor sites in urologic cancers.

METHODS

Review of comparative trials addressing quality criteria of imaging modalities.

RESULTS

Depending on primary tumor and metastatic site, conventional imaging modalities such as computer tomography (CT) and bone scintigraphy still represent the standard of care in Germany. Due to superior quality criteria, hybrid-imaging techniques were widely adopted for oncological staging and particular due to the new PSMA-ligand (PSMA-PET/CT) in prostate cancer imaging. The development of new radioisotopes as well as their clinical application remains a focus of current research.

CONCLUSIONS

High-quality diagnostic imaging modalities lay the groundwork for a precise definition of an oligometastatic state. By enabling treatment of the entire tumor burden, a delay of systemic therapy, longer progression-free survival, or even curative treatment may become achievable.

[Design and Evaluation of a Clinical Investigator Training for Student-lead Prospective Multicentre Clinical Trials: a CHIR-Net SIGMA Research-based Learning Project]

BACKGROUND

Scientific skills are not sufficiently taught during medical training, neither in medical school nor during postgraduate education. This results in a lack of clinician scientists. In order to counter this problem, the surgical study network (CHIR-Net) founded SIGMA (Student-initiated German Medical Audit). This paper describes the development, performance and evaluation of a Clinical Investigator Training (CIT) aiming to qualify students to autonomously conduct clinical trials.

MATERIAL AND METHODS

Based on the Kern cycle, a curriculum was developed, composed of three parts: online tutorials, a workshop and a follow-up period. The educational objectives were defined according to Bloom's taxonomy of knowledge. The learning objectives were based on the requirements of the "Network of Coordinating Centers for Clinical Trials" and the German Medical Association as well as content relevant to clinical studies. A wide range of educational instruments and assessments were used. By including all relevant professional groups involved in clinical trials, an interconnected working environment for students was generated. The increase in knowledge was assessed by a multiple-choice pre/post exam. The satisfaction of participants was analysed by a 5-point Likert scale, on which 5 indicated full approval.

RESULTS

The first SIGMA CIT was realised in 2018; the workshop took place in Heidelberg in February. Thirty-two medical students from thirteen different centres participated. On average, 53.8 ± 8.3% of questions were answered correctly in the pre-test, compared with 71.2 ± 7.2% in the post-test (p < 0.0001). The maximal individual improvement was 30%; the lowest difference compared to the pre-test was 5%. Subjective evaluation results were positive with an average result of 4.63 ± 0.34 on a 5-point Likert scale.

CONCLUSION

It is feasible to teach medical students the fundamentals of clinical trials. A compact Clinical Investigator Training using modern principles of teaching is able to prepare students for an autonomous performance of clinical trials.

Prospective multicentre cohort study of patient-reported outcomes and complications following major abdominal neoplastic surgery (PATRONUS) - study protocol for a CHIR-Net student-initiated German medical audit study (CHIR-Net SIGMA study)

BACKGROUND

One of the most important aspects of designing a clinical trial is selecting appropriate outcomes. Patient-reported outcomes (PROs) can provide a personal assessment of the burden and impact of a malignant disease and its treatment. PROs comprise a wide range of outcomes including basic clinical symptom scores and complex metrics such as health-related quality of life (HRQoL). There is limited data on how postoperative complications following cancer surgery affect symptoms and HRQoL. For this reason the primary aim of the PATRONUS study is to investigate how perioperative complications affect cancer-related symptoms and HRQoL in patients undergoing abdominal cancer surgery. The PATRONUS study is designed and will be initiated and conducted by medical students under the direct supervision of clinician scientists based on the concept of inquiry-based learning.

METHODS

PATRONUS is a non-interventional prospective multicentre cohort study. Patients undergoing elective oncological abdominal surgery will be recruited at regional centres of the clinical network of the German Surgical Society (CHIR-Net) and associated hospitals. A core set of 12 cancer associated symptoms will be assessed via the PRO version of the Common Terminology Criteria for Adverse Events. The cancer-specific HRQoL will be measured via the computerised adaptive testing version of the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30. PROs will be measured eight times over a period of six months. The short-term clinical outcome measure is the rate of postoperative complications (grade II to V) within 30 days according to the Clavien-Dindo classification. The long-term clinical outcome is overall survival within six months postoperative.

DISCUSSION

PATRONUS will provide essential insights into the patients' assessment of their well-being and quality of life in direct relation to clinical outcome parameters following abdominal cancer surgery. Furthermore, PATRONUS will investigate the feasibility of multicentre student-led clinical research.

TRIAL REGISTRATION

German Clinical Trials Register: DRKS00013035 (registered on October 26, 2017). Universal Trial Number (UTN): U1111-1202-8863.

Heidelberger Interprofessionelle Ausbildungsstation (HIPSTA): a practice- and theory-guided approach to development and implementation of Germany's first interprofessional training ward

Background: Deficits in care and impaired patient-safety have been linked to inefficient interprofessional collaborative practice. Interprofessional training wards (IPTW) are an interprofessional educational intervention which aim to enable students and trainees from different health professions to work self-responsibly in order to manage the medical treatment and rehabilitation of real-life patients together as an interprofessional team. We aimed to develop and implement Germany´s first IPTW at the department of Surgery at Heidelberg University Hospital. Methods: The Kern cycle was used to develop an ITPW curriculum. Practical as well as theoretical considerations guided the design of the IPTW. Common project management tools including blueprinting and RASCI (Responsibility, Approval, Support, Consultation, Information) matrix were applied. Results: Since April 2017, 7 cohorts of students and trainees have had four-week long placements on HIPSTA. They run the IPTW in early and late shifts. Nursing and medical facilitators are supporting the IP team as needed. Learning objectives are operationalized as EPAs (entrustable professional activities) and interprofessional learning goals. Since initiation only minor modifications to the curriculum have been necessary and satisfaction of students/trainees, facilitators and patients is high. Conclusion: IPTWs can be established and run in the German health care system even in a complex clinical setting. The early involvement of all professions in a steering group seems to be key to success. Nursing and medical facilitators are of utmost importance for daily routine. The experiences outlined here could help others aiming to implement IPTWs at their sites. IPTWs might address a number of hitherto unaddressed educational needs. Trial registration: Not applicable.

Encouraging student-driven clinical research in Germany: the CHIR-Net SIGMA network

Evidence should define and guide modern clinical care, yet many relevant questions in surgical practice remain unconfirmed by substantial data. Evidence-based medicine requires both the implementation of its principles in day-to-day work and the acquisition of new evidence preferably by randomized controlled trials and systematic reviews. Meaningful clinical research, however, is challenging to conduct, and its overall infrastructure in Germany was, until recently, considered poor compared to other leading countries. Although this has been significantly improved after the establishment of the Study Center of the German Surgical Society (SDGC) and the surgical clinical trial network CHIR-Net, limited focus has been put on the training, teaching, and recruitment of medical students to become competent clinical researchers and clinician scientists. To ensure continuing comprehensive clinical research in surgery, CHIR-Net aims to establish a student-driven multicenter research network in Germany, which is embedded in both the national CHIR-Net and the pan-European and international frameworks. Student-Initiated German Medical Audits (SIGMA) is a product of the strong collaboration between clinical scientists and medical trainees, enabling students to contribute to high-quality clinical trials. Additionally, participants are offered extensive training to support the next generation of research-active clinicians. Starting on 2018, SIGMA will perform its first multicenter observational study in Germany.

Synthesis and biological activity of novel potent endothelin-converting enzyme-1 inhibitors

Through directed screening of metalloprotease inhibitors, CGS 30084 (1) has been identified as a potent endothelin-converting enzyme-1 (ECE-1) inhibitor in vitro (IC50 = 77 nM). Herein we report the syntheses and biological activities of analogues derived from this lead, based on modifications of the biphenyl moiety. Compound 10, the thioacetate methyl ester prodrug derivative of compound 6m, was found to be an orally active and potent inhibitor of ECE-1 activity in rats.

Design and synthesis of potent thiol-based inhibitors of endothelin converting enzyme-1

Through directed screening of compounds prepared as metalloprotease inhibitors a compound, CGS 30084, that had potent endothelin converting enzyme-1 (ECE-1) in vitro inhibitory activity (IC50 = 77 nM) was identified. Herein we report the synthesis and optimization of ECE-1 inhibitory activity of additional analogues from this lead. Compound 3c, the thioacetate methyl ester derivative of compound 4c, was found to be a long acting inhibitor of ECE-1 activity in rats after oral administration.

Design and synthesis of thiol containing inhibitors of matrix metalloproteinases

A series of thiol containing derivatives was prepared. Several of these compounds were found to inhibit matrix metalloproteinases 1, 3, and 9 with selectivity towards 3 and 9. Compounds 15, 20, and 22 were administered to rats orally at 75 mumol/kg. Drug levels of compounds 20 and 22 in the plasma were found to exceed the IC50 values for MMP 3 and 9 four hours after administration.

Antihypertensive and natriuretic effects of CGS 30440, a dual inhibitor of angiotensin-converting enzyme and neutral endopeptidase 24.11

Dual angiotensin-converting enzyme (ACE)/neutral endopeptidase (NEP) inhibitors, by decreasing angiotensin-II production and by preventing the degradation of atrial natriuretic peptide (ANP), may be useful for the treatment of hypertension and congestive heart failure. The thiol dipeptide CGS 30440 (prodrug of CGS 30008, IC50: ACE/NEP = 19/2 nM) administered to rats (10 mg/kg p.o.) inhibited lung tissue ACE activity by 98% and 61% at 1 and 24 hr (P < .001) and inhibited the angiotensin-I pressor response by 75 to 90% for more than 6 hr. Renal tissue NEP activity was reduced by 80% at 1 hr and 73% at 24 hr (P < .001). In rats supplemented with exogenous ANP, CGS 30440 (1 mg/kg p.o.) elevated the concentration of circulating ANP (133%, P < .025) for 4 hr and increased the excretion of urine (300%, P < .001), sodium (194%, P < .025) and cyclic GMP (238%, P < .005). CGS 30440 (10 mg/kg p.o.) administered to hypertensive rats with aortic ligation between the renal arteries (mean arterial blood pressure, 209 +/- 4 mm Hg) produced a 48 mm Hg blood pressure reduction (P < .001) within 4 hr. CGS 30440 given to cynomolgus monkeys at 2 mg/kg inhibited plasma ACE activity by 96% within 1 hr (P < .001), and this inhibition was maintained for 7 and 21 days in monkeys receiving the compound orally at 2.5 mg/kg b.i.d. These studies demonstrate that CGS 30440 is an orally active agent which produces tissue ACE and NEP inhibition in rats and plasma ACE inhibition in primates and suggest that the compound may be useful in the treatment of hypertension and congestive heart failure.

Mercaptoacyl dipeptides as orally active dual inhibitors of angiotensin-converting enzyme and neutral endopeptidase

Dual inhibitors of the two zinc metallopeptidases, neutral endopeptidase (NEP, EC 3.4.24.11) and angiotensin-I-converting enzyme (ACE, EC 2.4.15.1), have been the focus of much clinical interest for the treatment of hypertension and congestive heart failure. We have previously reported that compound 2 (N-[[1-[(2(S)-mercapto-3-methyl-1-oxobutyl) amino]-1-cyclopentyl]-carbonyl]-L-tyrosine) was a potent dual inhibitor in vitro (IC50 (ACE) = 7.0 nM, IC50 (NEP) = 1.5 nM) (Fink et al. J. Med. Chem. 1995, 38, 5023-5030). This compound was found to have oral activity; however, its duration of effect was short. A series of thioacetate carboxylic acid ester analogs of compound 2 was prepared. Modifications were also made to the tyrosine phenol. These compounds were evaluated for their ability to inhibit plasma ACE activity when administered orally to conscious normotensive rats. Most of the compounds prepared were found to be orally active with longer durations of effect than compound 2. Compound 38 (N-[[1-[(2(S)-(acetylthio)-3-methyl-1-oxobutyl) amino]-1-cyclopentyl]carbonyl]-O-methyl-L-tyrosine ethyl ester), administered at 11.7 mg/kg po, was found to be more efficacious than captopril at 10 mg/kg po. This compound was also found to inhibit plasma NEP activity following oral administration to conscious rats and was more efficacious than acetorphan. Compound 38 was found to lower blood pressure in the aorta-ligated rat and the spontaneously hypertensive rat when administered orally. The synthesis and biological activity of these dual inhibitors are discussed.

Tyrosine hydroxylase- and nitric oxide synthase-immunoreactive nerve fibers in mitral valve of young adult and aged Fischer 344 rats

Using confocal fluorescence microscopy we studied, in whole mounts of heart mitral valves of young adult and aged Fischer 344 rats, the distribution of nerves containing the catecholamine marker tyrosine hydroxylase (TH) or the synthetic enzyme marker for nitric oxide, nitric oxide synthase (NOS). TH-IR was localized in two separate nerve plexuses which do not intermingle. The 'major' plexus arose from the annulus region, traversed the basal zone of the valve, and ramified in the intermediate zone to form a dense network of fine fibers. The 'minor' plexus was restricted to the distal zone and originated from bundles that ascended the chordae tendineae to enter the valve cusp. A concentric zone located between the major and minor plexuses was devoid of TH-IR nerve fibers. Both plexuses demonstrated (i) nerves that contained numerous varicosities along the length of each fiber, (ii) many terminal axons and (iii) different shaped terminal axon endings. With age, the density of TH-IR innervation in the mitral valve was markedly reduced; and nerve fibers of the minor plexus were limited to the chordae tendinae, without extending into the valve cusp itself. NOS-IR fibers in the mitral valve formed a loose network that extended from the annulus to more than halfway down the cusp. The varicose beads of the terminal NOS-IR axons appeared to become progressively smaller and less intensely fluorescent until they disappeared at the terminal endings, which showed no specializations. No NOS-IR fibers were observed in the distal zone of the valve leaflet or in the chordae. In the aged mitral valve, the density of NOS-IR nerves was decreased, as compared with NOS-IR innervation in the young adult valve. The existence of TH and NOS as well as other signal molecule markers in heart valve nerves and the disparate patterns of their distribution and localization provide evidence supporting the theory that heart valve nerves form a complex reflexogenic control system in the mitral heart valve. In summary, two distinct neural architectures are described for TH-IR and NOS-IR valve nerves, respectively. The former are believed to be axons dedicated to sympathetic motor functions. The NOS-IR valve nerves may have sensory and/or postganglionic parasympathetic motor functions. An implication of these findings is that different, but perhaps related, valve functions may be mediated by separate, dedicated circuits.

Differential effects of the BKCa channel openers NS004 and NS1608 in porcine coronary arterial cells

The effects of newly claimed BKCa channel openers NS004 (5-trifluoromethyl-(5-chloro-2-hydroxyphenyl)-1,3-dihydro-2H-benzimidazo le-2- one) and NS1608 (N-(3-(trifluoromethyl)phenyl)-N'-(2-hydroxy-5-chlorophenyl)urea) were investigated on whole-cell K+ current (IK) in enzymatically isolated porcine coronary arterial cells using patch-clamp technique with a double holding potential protocol. When cells were held at 0 mV, IK was augmented by NS004 in a concentration-dependent manner. With a holding potential of -60 mV, however, IK was moderately inhibited by NS004 between 0.5 and 10 microM, but robustly stimulated by 50 microM NS004 at highly depolarized potentials. The effects of NS1608 on IK did not differ due to change in holding potential. At -60 mV and 0 mV, NS1608 activated IK with bell-shaped concentration-response curves peaked between 5 and 10 microM. The differential mode of action of the two compounds suggested an involvement of mechanism(s) other than an opening of BKCa channel.

New alpha-thiol dipeptide dual inhibitors of angiotensin-I converting enzyme and neutral endopeptidase EC 3.4.24.11

Dual inhibitors of the two zinc metallopeptidases, neutral endopeptidase (NEP, EC 3.4.24.11) and angiotensin-I converting enzyme, have been the focus of much clinical interest for the treatment of hypertension and congestive heart failure. A novel series of alpha-thio dipeptides containing central cyclic non-natural amino acids were prepared and were evaluated for their ability to inhibit these two metallopeptidases in vitro and in vivo. Most of these compounds were found to be excellent dual inhibitors of ACE and NEP in vitro and several were also found to inhibit angiotensin-I (AI) pressor response in conscious rats when given by intravenous administration. Compound 6n, one of our most potent dual inhibitors in vitro, was found to be more efficacious than captopril in the AI pressor experiment when administered orally to conscious rats. This compound was also found to inhibit plasma NEP activity following oral administration to conscious rats and was more efficacious than acetorphan. The structure-activity relationships and biological activity of these dual inhibitors will be discussed.

Early angiography cannot predict postthrombolytic coronary reocclusion: observations from the GUSTO angiographic study. Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries

OBJECTIVES

The purpose of this study was to determine whether early qualitative or quantitative angiographic features can predict reocclusion after initially successful coronary thrombolysis.

BACKGROUND

Although both the benefits of early reperfusion and the consequences of subsequent reocclusion after thrombolysis for acute myocardial infarction have been well described, efforts to describe angiographic markers of lesions at high risk for reocclusion have produced conflicting results. The Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO) angiographic trial provides the opportunity to examine these relations in the largest single, prospective patient cohort studied to date.

METHODS

We studied 559 patients undergoing follow-up angiography at 90 min and 5 to 7 days after thrombolysis in the GUSTO trial. Patients received one of four thrombolytic regimens: 1) streptokinase with intravenous heparin; 2) streptokinase with subcutaneous heparin; 3) accelerated-dose recombinant tissue-type plasminogen activator (rt-PA) with intravenous heparin; or 4) a combination of streptokinase and conventionally dosed rt-PA with intravenous heparin. Qualitative variables examined at 90-min angiography included Thrombolysis in Myocardial Infarction (TIMI) flow grade, visible thrombus and lesion morphology. Quantitative variables included percent diameter stenosis, percent area stenosis, minimal lumen diameter and lesion length. The study contained a power > 0.85 to detect clinically important differences in percent diameter stenosis, percent area stenosis and minimal lumen diameter between the groups with subsequent reocclusion and sustained patency at the p = 0.05 level.

RESULTS

At follow-up, 33 patients (5.9%) had reocclusion. The reocclusion rate for patients with early TIMI grade 2 flow was 6.3% versus 5.6% for TIMI grade 3 flow (p = NS). When the group with reocclusion was compared with the group with continued patency, there were no differences in presence of early visible thrombus, complex lesion morphology, percent diameter stenosis, percent area stenosis, minimal lumen diameter or lesion length.

CONCLUSIONS

Our findings demonstrate that neither qualitative nor quantitative angiographic variables at 90 min after initiation of thrombolytic therapy can be used to predict subsequent coronary reocclusion.

The hydration pressure between lipid bilayers. Comparison of measurements using x-ray diffraction and calorimetry

The hydration pressure between dipalmitoyl phosphatidyl-N,N-dimethylethanolamine (DPPE-Me2) bilayers has been analyzed by both x-ray diffraction measurements of osmotically stressed liposomes and by differential scanning calorimetry. By the x-ray method, we obtain a magnitude (Po) and decay length (lambda) for the hydration pressure which are both quite similar to those found for bilayers of other zwitterionic lipids, such as phosphatidylcholines. That is, x-ray analysis of DPPE-Me2 in the gel phase gives lambda = 1.3 A, the same as that previously measured for the analogous gel phase lipid dipalmitoylphosphatidylcholine (DPPC), and Po = 3.9 x 10(9) dyn/cm2, which is in excellent agreement with the value of 3.6 x 10(9) dyn/cm2 calculated from the measured Volta potential of DPPE-Me2 monolayers in equilibrium with liposomes. These results indicate that the removal of one methyl group to convert DPPC to DPPE-Me2 does not markedly alter the range or magnitude of the hydration pressure. Calorimetry shows that the main gel to liquid-crystalline phase transition temperature of DPPE-Me2 is approximately constant for water contents ranging from 80 to 10 water molecules per lipid molecule, but increases monotonically with decreasing water content below 10 waters per lipid. A theoretical fit to these temperature vs. water content data predicts lambda = 6.7 A. The difference in observed values of lambda for x-ray and calorimetry measurements can be explained by effects on the thermograms of additional intra- and intermolecular interactions which occur at low water contents where apposing bilayers are in contact. We conclude that, although calorimetry provides important data on the energetics of bilayer hydration, it is difficult to obtain quantitative information on the hydration pressure from this technique.