Tele-chemotherapy and related outcomes to improve rural cancer care

142

Background: We previously reported the safety and feasibility of tele-chemotherapy with remote administration of chemotherapy (chemo) in rural hospitals using experienced chemo nurses with direct supervision from medical oncologist at a tertiary site. Herein we report the detailed overview of types of cancers treated, chemo-regimens administered and associated outcomes within an integrated health system. Methods: We retrospectively analyzed 200 patients who received chemotherapy remotely in 4 rural health hospitals in the state of Utah between 2017- 2022. Data collected included age of administration of chemo, gender, cancer type, insurance, chemotherapy regimen, number of cycles, emergency visits, hospitalizations, and infusion reactions. Results: 200 pts received chemotherapy at 4 rural hospitals including Sevier Valley Hospital, Cassia Regional Hospital, Sanpete Valley Hospital, and Heber Valley Hospital in Utah and Idaho. Median age of administration was 53 yrs (11- 96 yrs). Majority were male (n = 118; 59%). Insurances that covered these services included Medicare, Medicaid, Regence Blue Cross, United Healthcare, Tricare and Select Health. The most common cancer types treated included – Colorectal (n = 31), Breast (n = 24), Lung (n = 15), Lymphoma (n = 21), Multiple Myeloma (n = 11), Melanoma (n = 9), Bladder (n = 7), and other benign conditions (n = 25). 47 unique chemo regimens including 1085 cycles were administered. Chemo regimens and cycles detailed below. Among 69 pts with outcomes data available, ED visits noted in 33% (n = 23), hospitalization rate was 17% (n = 12) and infusion reaction rate was 7% (n = 5). Total mileage saved by pts receiving chemotherapy closer to home was 47,955 miles. Conclusions: Tele-chemotherapy is safe, feasible and provides improved access to cancer care in rural areas. Future design of pragmatic clinical trials where remote administration of standard of care treatments closer to home will allow the rural pts access cutting edge clinical trials closer to home.[Table: see text]

Complementary and alternative medicine exposure in oncology (CAMEO) study: A multi-institutional cross-sectional analysis of patients receiving cancer treatment

e18739

Background: Compared to standard of care treatments, complementary and alternative medicine (CAM) use has been associated with decreased survival in cancer patients. CAM includes a broad range of treatments including vitamins/minerals, herbs/supplements, special diets, and mind/body interventions. An improved understanding of contemporary prevalence, predictors and intended goals of CAM use is needed to improve the cancer patient experience and guide shared decision-making regarding risks and benefits of their use. Methods: A cross-sectional survey of prospectively enrolled adult cancer patients treated at a large regional non-profit cancer center and an NCI-Designated Comprehensive Cancer Center between 2020 and 2021 was collected. Patients receiving cancer treatment were selected for analysis and grouped based on reported CAM use. Differences between CAM users and nonusers were assessed by chi-squared for categorical and two-sample t-test for continuous variables. Predictors of CAM use were identified with univariable and multivariable logistic regression. Results: Of 749 respondents, 83.31% had heard of or been recommended a CAM. Rates of CAM use during cancer treatment were highest for vitamins/minerals (56%), mind/body (52%), herbs/supplements (38%), special diets (30%), and other (12%). In the most common primary cancers, overall rates of CAM use were high (Breast: 84%, prostate: 66%, lung: 79%). Most patients (91%) use CAM in addition to conventional treatments. The intended goal of CAM therapy was most often management of symptoms (42%), treatment of cancer (30%), and mental health (15%). CAM users were younger than non-users (median age 62 years [y] vs 65y, p = 0.03). Females had higher rates of CAM use compared to males (86% vs. 78%, p < 0.01). Patients with incurable cancer had higher rates of CAM use than those with curable cancer (82% vs. 72%, p < 0.01). Predictors of CAM use on multivariable model include female gender (OR 2.5, p < 0.01) and incurable cancer (OR 2.5, p < 0.01). During cancer treatment, patients using CAM used multiple therapies and therapy types, including an average of 3.3 vitamins/minerals, 3.1 herbs/supplements, 2.5 mind/body exercises, and 1.6 special diets. Conclusions: CAM use is common among cancer patients receiving radiation, chemotherapy, and or surgery. Many patients are taking multiple CAM therapies during treatment with one third of patients using CAM with the intended goal of treating their cancer. This data provides details about and predictors of CAM use and provides information to guide patient-physician discussions.

Shifting perceptions of alternative therapies in cancer patients during the COVID-19 pandemic: Results from the Complementary and Alternative Medicine Exposure in Oncology (CAMEO) Study

e24130

Background: Complementary and alternative medicine (CAM) use has been associated with worse survival outcomes in cancer patients compared to standard of care therapies. CAM has received a significant increase in public awareness and interest in the COVID-19 pandemic era. We sought to understand how the COVID-19 pandemic affected CAM use and perceptions in cancer patients. Methods: Data was collected from adult cancer patients prospectively enrolled on a cross-sectional survey conducted at an NCI-designated cancer center and a comprehensive cancer center between 2020 and 2021. The survey included questions assessing changes in patient attitude towards CAM and likelihood of using CAM, both relative to prior to COVID-19. Analyzed CAM users included those taking vitamin, mineral and herbal supplements, alternative medicines and special diets, and excluded mind-body practices as the focus of this analysis was on enteral and parenteral CAM therapies. Differences in the impact of COVID-19 on CAM use beliefs and practices between CAM users and non-users were analyzed with χ2 and two-sample t-tests. Results: Out of 749 respondents, 578 (77%) used any CAM and 470 (63%) used enteral or parenteral CAM. Results shown in table. Compared to prior to COVID-19, CAM users were more likely to view CAM more favorably (12% vs 5%, p < 0.01), while non-users were more likely to have an unchanged opinion (90% vs 84%, p = 0.03). Females had higher rates of viewing CAM more favorably than males (80% vs 58%, p = 0.04). Patients who viewed CAM more favorably had higher rates of self-reported incurable cancer (36% vs 11%, p = 0.04), declining recommended hormone therapy (22% vs 0%, p < 0.01), and higher trust of social media (19% vs 0%, p = 0.02) and websites (24% vs 0%, p < 0.01). Since the start of COVID-19, CAM users were more likely to report increased likelihood of using CAM (12% vs 6%, p = 0.01). Patients who were more likely to use CAM had higher rates of declining recommended chemotherapy (12% vs 0%, p = 0.02), and higher trust of social media (15% vs 2%, p = 0.01) and websites (28% vs 7%, p < 0.01). Conclusions: During the COVID-19 pandemic, attitudes on CAM use in oncology patients have become increasingly polarizing. Patients with favorable attitudes toward CAM were likely to decline recommended standard of care therapy and more like to use CAM since COVID-19. This data helps characterize shifting attitudes toward CAM and may help guide shared decision-making between physician and patient.[Table: see text]

Impact of provider education on prostate cancer genetic counseling referrals

59

Background: Guidelines recommend germline genetic not only for men with advanced and metastatic prostate cancer but also those with NCCN-high risk disease. Many men harboring germline DNA repair defects would not have met criteria for testing under previous guidelines (Nicolosi et al, JAMA Oncol 2019). Knowledge of germline mutations is pertinent due to recent regulatory approval of PARP inhibitors olaparib and rucaparib and guides screening for first-degree relatives who are at increased risk for other cancers (Pritchard et al, NEJM 2016). Knowledge gaps for germline genetic testing have been previously described (Loeb et al, Cancer Treat Res Commun 2020). Through a series of educational sessions, we sought to increase utilization of appropriate genetic services for men with prostate cancer. Methods: Starting March 2021, virtual educational presentations were held for nurse navigators, urologists, and medical oncologists throughout our large community-based healthcare system. Surveys were distributed following each presentation to measure clinicians’ perception of their knowledge regarding prostate cancer genetics referrals on a five-step scale. Prostate cancer patient referral data was measured from September 2020 to August 2021, six months prior to and after the presentations. Results: Self-reported understanding of prostate cancer genetics referral practices following the educational presentations increased by an average of 1.7/5 steps (2.5 to 4.2/5) for physicians and 1.4/5 steps (2.9 to 4.1/5) for nurse navigators. From March to August 2021, there were 107 genetic referrals for prostate cancer (average 17.8 referrals/month) compared to 49 referrals from September 2020 to February 2021 (8.2 referrals/month). Conclusions: Prostate cancer genetics referrals increased 118% following educational presentations to urologists, medical oncologists, and nurse navigators. This correlates with an improvement in self-reported knowledge gaps. Provider education interventions may improve access to genetic services for men with prostate cancer. The increase in referrals likely does not account for all patients meeting criteria for germline testing. Work is ongoing to calculate the number of referrals as a proportion of the eligible population.[Table: see text]

Feasibility of tele-chemotherapy administration to improve access to rural cancer patients

112

Background: Telehealth improves access to cancer care for patients with cancer in rural communities. It allows qualified infusion nurses to administer chemotherapy in smaller rural towns under supervision by health professionals from larger tertiary sites. Here we would like to share our institutional experience in tele-chemotherapy administration to patients in rural Utah. Methods: We collected patient data including treatment regimens administered at our tele health sites from March 2019 to February 2021. Results: A total of 133 unique patients received 1073 cycles of low to intermediate risk treatment regimens. 42 unique regimens including intravenous and oral chemotherapy drugs, immune therapy and targeted drugs were administered at four rural facilities including Cassia Regional Center, Sanpete Valley Hospital, Severe Valley Hospital and Heber Valley Hospital in Utah. 52 physicians located at tertiary sites were involved in tele-chemotherapy administration. In addition to Medicare, Medicaid, the tele chemotherapy was covered by four commercial payers including Blue Cross Blue Shield, Select Health, Tricare and United Healthcare. Conclusions: Tele chemotherapy administration is feasible and allows improved access to cancer patients in rural communities. We aim to expand current project to capture the patient satisfaction and clinical outcomes including treatment delays, dose modifications, infusion reactions, hospitalizations or emergency visits.

Barriers to patient-centered oncology care: Pilot study of home infusion of anticancer immunotherapy

36

Background: ASCO published a position statement regarding home infusion of anticancer therapy in June 2020. This statement recommends independent research to evaluate the safety and effectiveness of home infusions. Intermountain Healthcare (IM) incorporated this statement into its oncology care with an IRB-approved, prospective single-arm pilot study to determine the safety and feasibility of home administration of checkpoint inhibitor (CPI) immunotherapy with synchronous telemedicine visits. Methods: Patients with cancer receiving treatment at Intermountain Medical Center and Intermountain Cancer Center St. George were screened for enrollment into an IRB-approved, non-randomized pilot study of 20 patients. Eligibility criteria required patients to receive a CPI for an FDA-approved indication, live in Washington County or Salt Lake County, Utah, and have commercial payer coverage of CPI home infusion. Eligible patients were required to receive 2 doses of CPI at an infusion center, and patients who experienced an infusion reaction were excluded from receiving home infusion. Home infusion nurses are trained in oncology, CPIs, and home infusion reaction protocol. During synchronous video visits, infusion nurses are trained to perform the hands-on portions of the physical exam. A financial analysis estimated cost to IM and commercial payers for routine and home CPI infusions. Results: 622 patients were screened, of which 104 were receiving a CPI. 64 patients lived in an eligible county and 19 patients had commercial payer coverage. Of patients on CPIs, 8.7% (9/104) met all eligibility criteria accounting for 1.4% (9/622) of all patients with cancer screened (Table). Financial analysis estimated $829 cost (excluding drug cost) to IM for standard infusion reimbursement compared to $599 for in-home CPI infusions, accounting for savings of $230 per infusion. Majority of cost savings are from elimination of infusion center facilities fee ($495). Analysis includes $269 for home infusion nurse wages. Subsequent analysis for commercial payer SelectHealth estimates $270 reimbursement savings for the payer. Conclusions: Home immunotherapy infusions are estimated to be cost effective for both IM and commercial payers. However, lack of drug coverage and the rural demographics of Utahns with cancer are barriers to home CPI infusions. The pilot study was discontinued per infeasibility stopping criteria.[Table: see text]

Association of clinical factors and recent anticancer therapy with COVID-19 severity among patients with cancer: a report from the COVID-19 and Cancer Consortium

BACKGROUND

Patients with cancer may be at high risk of adverse outcomes from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We analyzed a cohort of patients with cancer and coronavirus 2019 (COVID-19) reported to the COVID-19 and Cancer Consortium (CCC19) to identify prognostic clinical factors, including laboratory measurements and anticancer therapies.

PATIENTS AND METHODS

Patients with active or historical cancer and a laboratory-confirmed SARS-CoV-2 diagnosis recorded between 17 March and 18 November 2020 were included. The primary outcome was COVID-19 severity measured on an ordinal scale (uncomplicated, hospitalized, admitted to intensive care unit, mechanically ventilated, died within 30 days). Multivariable regression models included demographics, cancer status, anticancer therapy and timing, COVID-19-directed therapies, and laboratory measurements (among hospitalized patients).

RESULTS

A total of 4966 patients were included (median age 66 years, 51% female, 50% non-Hispanic white); 2872 (58%) were hospitalized and 695 (14%) died; 61% had cancer that was present, diagnosed, or treated within the year prior to COVID-19 diagnosis. Older age, male sex, obesity, cardiovascular and pulmonary comorbidities, renal disease, diabetes mellitus, non-Hispanic black race, Hispanic ethnicity, worse Eastern Cooperative Oncology Group performance status, recent cytotoxic chemotherapy, and hematologic malignancy were associated with higher COVID-19 severity. Among hospitalized patients, low or high absolute lymphocyte count; high absolute neutrophil count; low platelet count; abnormal creatinine; troponin; lactate dehydrogenase; and C-reactive protein were associated with higher COVID-19 severity. Patients diagnosed early in the COVID-19 pandemic (January-April 2020) had worse outcomes than those diagnosed later. Specific anticancer therapies (e.g. R-CHOP, platinum combined with etoposide, and DNA methyltransferase inhibitors) were associated with high 30-day all-cause mortality.

CONCLUSIONS

Clinical factors (e.g. older age, hematological malignancy, recent chemotherapy) and laboratory measurements were associated with poor outcomes among patients with cancer and COVID-19. Although further studies are needed, caution may be required in utilizing particular anticancer therapies.

CLINICAL TRIAL IDENTIFIER

NCT04354701.

Incidence and cost of radical prostatectomy for NCCN low-risk prostate cancer in Utah

232

Background: Guidelines Support active surveillance (AS) as the preferred treatment for men with NCCN low-risk prostate cancer (Gleason 3+3, prostate-specific antigen [PSA] <10 ng/ml, ≤T2a). Recent work from Mahal BA et al. (JAMA 2019) reports AS rates are increasing, but only 42.1% of men with low-risk prostate cancer underwent AS in 2015. Low-risk prostate cancer accounted for 30.1% of diagnoses. The majority of Utah residents treated for prostate cancer receive therapy at either The Huntsman Cancer Institute or Intermountain Healthcare facilities. We modeled the costs associated with the presumptive overtreatment of men with low-risk disease treated in 2017-2019. Methods: Data from The Huntsman Cancer Institute and Intermountain Healthcare cancer databases from 2017 to 2019 were retrospectively analyzed. Men with available pathologic, laboratory and clinical data who had undergone prostatectomy were stratified by having NCCN low, intermediate, and high-risk disease. Rates of radical prostatectomy by year and institution were analyzed. The cost of prostatectomy compared to AS was estimated to be $14,453 from recent work by Trogdon JG et al. (JAMA Oncol 2019). Results: Data was available for 1,155 Utahn men (Table). Of the 1155 surgeries performed, 69 (6%) were in low-risk patients. The total costs of care that might have been avoided over these three years are estimated to be $1 million. Conclusions: Approximately 6% of prostatectomies performed in Utah are in men with NCCN low-risk prostate cancer. While these rates are lower than the national average, we estimate approximately $1 million in medical costs and toxicities could be deferred had these patients opted for AS. Work is ongoing to characterize clinical toxicity of treatment in these men, and a multi-institutional collaborative education outreach program to reduce overtreatment is in development. [Table: see text]

Cost savings of biosimilars in oncology: A single institution experience

10

Background: Biosimilar medications have increasingly gained regulatory approvals in recent years. Numerous conditions in the fields of hematology, oncology, rheumatology, and endocrinology have a biosimilar treatment option available. Some biosimilar agents can be obtained at a significantly lower cost than reference medications. Methods: Intermountain Healthcare Oncology Pharmacy and Therapeutics (P&T) committee manages and maintains the formulary of accepted drugs. The committee consists of pharmacists, medical oncologists and oncology nurses. Biosimilar medications were approved in place of reference medications for the following: pegfilgrastim, bevacizumab, trastuzumab, and rituximab. Results: Annually, we administer about 6,450 combined doses of pegfilgastrim, bevacizumab, trastuzumab, and rituximab. Assuming 70% conversion from the reference medication to biosimilar agent, transitioning from the above listed reference medications to biosimilar would save an estimated $6.3 million annually (Table). This includes a $1.75 million savings from transitioning to rituximab alone. In addition, transitioning trastuzumab from a single dose vial to multi-dose vials is estimated to save an addition $730,000. Conclusions: Biosimilar agents can reduce the cost of oncology care to patients treated at our institution. We are utilizing biosimilar agents as part of our ongoing mission to decrease the financial toxicity of treatment for patients with cancer. [Table: see text]

Telehealth to expand access of oncology care in Utah during COVID-19 pandemic

267

Background: Intermountain Healthcare has used telehealth since 2015 to expand oncology care for patients living in rural Utah communities. Telehealth services have historically not been widely available to patients living in non-rural locations due to restrictions in reimbursement policies. Changes during the COVID-19 pandemic, including the 1135 waiver authority and the Coronavirus Preparedness and Response Supplemental Appropriations Act, allows for reimbursement of provider professional fees for electronic visits occurring at any location including a patient’s home. This has allowed greater access to telehealth care for patients with cancer, many of whom are at increased risk of contracting SARS-CoV-2. Methods: Patient visits from Intermountain Healthcare’s two largest oncology sites, Intermountain Medical Center and Dixie Regional Medical Center, were evaluated from the electronic health record (iCentra). Four types of encounters were considered “televisits”: scheduled video visits (SVVs), alternative video visits (AVVs), telehealth visits, and phone visits. All visits were synchronous. Patients were seen from home except for telehealth visits where patients were seen remotely from a rural Intermountain site. SVVs occurred over Intermountain’s Connect Care software platform. AVVs utilized a non-Intermountain software such as FaceTime, Google Duo, Skype, or Webex. Visits were analyzed from December 1, 2019 to June 1, 2020. Results: From December 2019 to May 2020, there were 1,798 televisits performed. Three-month televisit totals increased from 175 from December-February to 1,623 from March-May (Table). Intermountain Medical Center increased televisits from 8 to 514 over these same time periods. Conclusions: Televisits have been utilized to maintain continuity of oncology care while minimizing patients’ exposure to healthcare facilities. On May 15, 2020, Governor Gary Herbert issued an executive order de-escalating Utah COVID-19 risk phase from moderate to low-risk. This may be associated with the decrease in televisits from April to May. [Table: see text]

Concordance of MRI-guided and systematic prostate biopsy for the detection of prostate cancer (PCa)

277

Background: MRI/US guided biopsy (fusion biopsy) is increasingly utilized over systemic 12-core transrectal ultrasound biopsy (12-core biopsy) for men with MRI-visible prostate lesions. Methods: Patients with MRI visible prostate lesions who underwent fusion and 12-core biopsy from 2016-2020 in the Intermountain Healthcare (IHC) system were consecutively analyzed. This was in the setting of a continuous quality assurance initiative among the reading radiologists. Primary outcome was PCa detection defined by Gleason grade group (GGG) 1 or higher. Clinically significant cancer (CSC) was defined as GGG 2 or higher. Patients were stratified by date biopsy was performed, 2016-2017 and 2018-2020, and lesions were stratified by PI-RADS v2 category. For men with multiple lesions, the highest PI-RADS v2 category lesion was used. Results: A total of 142 men with 254 MRI-detectable lesions underwent both fusion and 12-core biopsies in the IHC system from 2016 to 2020. CSC was detected in 21.6% (55/254) of fusion biopsies. Comparing PI-RAD v2 categories 1-3 to PI-RADS v2 categories 4-5, the PPV for detecting CSC was 9% (15/162) compared to 44% (40/92) respectively. Fusion and 12-core biopsies were concordant for any PCa in 79% of men (112/142) and CSC in 83% (118/142). Fusion biopsy detected any PCa in 22/84 (26%) and CSC in 15/103 (15%) of men in whom 12-core biopsy was negative. 12-core biopsy detected any PCa in 8/70 (11%) and CSC in 9/97 (9%) of men in whom fusion was negative. In total, 15 patients (11%) had a CSC that would have been missed if fusion biopsy was omitted while 9 (6%) had a CSC that would have been missed without 12-core biopsy. Conclusions: Omitting fusion or 12-core biopsy for PI-RADS v2 lesions would have resulted in a missed CSC in 11% or 6% of patients from 2016-20, respectively. The combination of MRI/US-guided fusion biopsy and systematic 12-core biopsy increased detection rate of CSC. These results are in the setting of a continuous, multi-disciplinary quality assurance program and results are not necessarily applicable to other healthcare systems. [Table: see text]

Implementation of 11 system-wide, disease-specific, multidisciplinary tumor boards connecting 24 hospitals in an integrated health care system

e19152

Background: Cancer treatment is becoming more complex, necessitating subspecialty expertise and multidisciplinary approaches to treatment planning. Simultaneously, there is increasing demand to provide care as close to home as possible. While tumor boards have long been an institutional backbone to providing high-quality multidisciplinary care in tertiary facilities, connecting several hospitals and dozens of cancer specialists in a large integrated healthcare system is unique and potentially transformational for smaller facilities and communities. Methods: Using highly-secure, network firewall-protected Cisco Telepresence and WebEx capabilities, 11 disease specific tumor boards (Breast, GI, Sarcoma, GU, Thoracic, Head/Neck, Melanoma, Neuro, Heme, Hepatobiliary, Gyn) were organized across Intermountain Healthcare’s 24 geographically and medically diverse hospitals spanning over 500 miles. Meetings for each of these disease-specific tumor boards have been held at least every 1-2 weeks, at set times and days since July 2019. Cases are submitted to the appropriate tumor board by individual providers from anywhere in the system. Submitted cases are reviewed by a designated subspeciality leader. Cases are either added to the system-wide agenda, or at times, the clinical decision can be resolved immediately. Included cases’ records including pathology, radiology and pertinent medical history are obtained for display and discussion. After each tumor board, recommendations and conclusions are recorded by nurse navigators for future review and consultation. Results: From July 2019 to February 2020, 1,598 patient cases were discussed. Just as relevant, 293 unique oncology providers (surgeons, medical oncologists, radiation oncologists, genetic counselors, nurse navigators, and therapists) participated in tumor board discussions. These deliberations provided insight, experience and recommendations directly related to patient care. Conclusions: Our system-wide, disease-specific, multi-disciplinary tumor boards are useful in connecting oncology providers and subspecialists. This effort has led to better collaboration, coordination and delivery of high-quality cancer care to patients throughout a large healthcare system that includes thousands of patients and dozens of cancer providers in smaller/rural communities. In addition, provider engagement has improved. Work is ongoing to prospectively evaluate the effects on treatment decisions and clinical outcomes.

Using a tele-oncology service provides a direct benefit to patients and caregivers in rural communities in the Intermountain West

e14153

Background: Cancer treatment is becoming more complex, necessitating subspecialty expertise and multidisciplinary approaches to treatment planning. Simultaneously, there is increasing demand to provide care as close to home as possible. Oncology services are in high demand with a geographical mismatch between where oncologists work and where patients live. Traditionally, patients have been required to travel long distances to seek care outside of their communities resulting in increased financial expense and emotional distress caused by leaving the comforts of their support system. Leveraging existing technologies, most of modern cancer care, including infusions can be delivered through a coordinated effort from consulting/ordering oncologists, onsite administrators, physicians, nurses and ancillary staff. Methods: Using a secure video-conferencing platform, Intermountain Healthcare has implemented 5 tele-oncology clinics (Site A- Sevier, UT; B- Cassia, ID; C- Teton, ID; D- Uintah Basin, UT, E- Star Valley, WY) in rural communities of Utah, Idaho and Wyoming. Patients are referred to the clinic by local providers. With the assistance of a nurse navigator, oncologists meet with patients via video conference for initial consults, follow-up, supportive care, survivorship care and systemic treatment including chemotherapy, immunotherapy, and targeted therapy. Standard NCCN/ASCO guidelines are followed in the treatment strategies for these patients. Care is taken to ensure any treatment that can safely be delivered in the local facility/community is coordinated to take place there. Based on distances from the rural facility to nearest tertiary cancer center, we calculated the mileage avoided and hours traveled avoided by using tele-oncology. Results: Since 2017, the tele-oncology service has managed 269 unique patients (A- 200; B- 21, C- 22, D- 18, E- 8) with 1,237 total tele-oncology visits (A- 1,068; B- 69; C- 39; D- 32; E- 29). In total, there were 397,326 driving miles avoided (A- 326,808; B- 26,358; C- 22,932; D- 9,280; E- 11,948). Travel hours avoided in total were 6,062 hours (A- 4,989; B- 380; C- 341; D- 155; E- 197). Conclusions: Intermountain Healthcare’s tele-oncology program benefits patients and communities by easing travel burden and improving quality of life by making cancer care more convenient and providing the care closer to home. Work is ongoing to prospectively evaluate the effects on the communities in addition to cancer related outcomes.

Accuracy of prostate imaging reporting and data system (PI-RADS v2) in the detection of prostate cancer (PCa)

e17604

Background: MRI-targeted biopsy is increasingly utilized over standard 12-core transrectal ultrasound (TRUS) biopsy for men with MRI-visible prostate lesions. Some clinicians defer biopsy for PI-RADS v2 category 1 and 2 lesions per the PRECISION Study (Kasivisvanathan et. Al, NEJM, 2018). The aim of this study was to independently validate the accuracy of PI-RADS v2 in detecting prostate cancer (PCa) when applied to MRI/US fusion-guided biopsies in an independent cohort of 156 patients from a large integrated community health system. Methods: Men undergoing MRI/US fusion-guided biopsy from 2016-2020 in the Intermountain Healthcare system were consecutively analyzed in this retrospective study. MRI were interpreted from four abdominal fellowship trained radiologists all with at least 5 years of experience. Fusion biopsies were performed by two urologists. Men were stratified into groups based on their PI-RADS v2 category 1-5. Biopsies were considered positive when Gleason ≥3+3. Results: A total of 156 men had 258 lesions for which they underwent MRI/US fusion-guided biopsies in the Intermountain Healthcare system from 2016 to 2020. The PCa detection rate for PIRADSv2 category 1-2 was 29.8%, category 3 32.6%, and category 4-5 37.6%. PIRADS v2 category 1, 2, 3, 4, and 5 yielded any PCa in 25, 15.9, 23.8, 53.1, and 66.7%, respectively (Table). PIRADS v2 category 1-2, 3, and 4-5 yielded any PCa in 16.8%, 23.8%, and 57.7%, respectively. Conclusions: PI-RADS v2 categories generally correlate with PCa detection rates, however, to avoid biopsy, the test must be both sensitive and specific, with low false negative rates. In our institution, we show that PI-RADS 1, 2, and 3 do not rule out the presence of PCa, and therefore should not be used as the sole factor in determining the need for prostate lesion biopsy. [Table: see text]

Survival outcomes according to the tumor mutation burden and PD-L1 expression in hepatobiliary tumors

566

Background: Hepatobiliary (HB) tumors are aggressive tumors with emerging evidence for increasing sensitivity to immune checkpoint inhibitors (ICI). Tumor mutation burden (TMB) was found to be a quantitative biomarker associated with production of neoantigens within the tumor and predict the sensitivity to immune therapy. Herein, we explore the TMB, microsatellite instability (MSI) and PD-L1 expression as a potential biomarker of response to immune therapy in HB tumors. Methods: We retrospectively assessed all patients with hepatobiliary malignancies who have undergone next generation sequencing (NGS) between October 2009 and June 2019. We then analysed the tumor mutation burden and PD-L1 of these tumors and also identified frequency of patients with no clinically actionable mutations. Results: In our total 61 patients with HB tumors predominantly were male (62.3%) with mean age of 63 years. Thirty-four patients had hepatocellular carcinoma, 22 patients had cholangiocarcinoma and 5 patients had gallbladder carcinoma. The most common risk factors were smoking status, cirrhosis, alcohol consumption and hepatitis C virus. The mean TMB reported was 3.2 (1.16 – 7.35). MSI was identified in 13 patients and one was indeterminate. Only 17 patients had PD-L1 positive. At least, 37 patients had one clinically actionable mutation while 24 patients had no clinically actionable mutations. Mean overall survival was 16.6 months, but no statistically significant difference was found by high PD-L1 (3 vs 3.7 months, p=0.3) expression. Conclusions: Our data suggests the TMB in HB tumors is low in general irrespective of their underlying risk factors. We also noted more than half had microsatellite stable tumors and PD-L1 expression. Future larger studies are needed to evaluate TMB, MSI and PD-L1 as a potential biomarker in hepatobiliary tumors to help select patients that will benefit from immune therapy.

Germline variant in HSD3B1 (1245 A>C) and response to abiraterone acetate plus prednisone (AA) in men with new onset metastatic castration-resistant prostate cancer (mCRPC)

173

Background: The HSD3B1 gene encodes the enzyme 3β-hydroxysteroid dehydrogenase-1 (3βHSD1), which catalyzes adrenal androgen precursors into dihydrotestosterone, the most potent androgen. Recently, multiple reports validated the role of HSD3B1 (1245 A>C) variant in predicting response to androgen deprivation therapy (ADT) in castration sensitive prostate cancer. The objective of this study was to correlate HSD3B1 variantwith response AA in first-line therapy for men with mCRPC. Methods: Clinical data and samples were from a prospectively maintained prostate cancer registry at the University of Utah. Genotyping was performed as described by Hearn at al (Lancet Oncology, 2016). Primary endpoint was progression-free survival in first-line AA in men with mCRPC. We performed pre-specified multivariate analyses to assess the independent predictive value of HSD3B1 genotype on PFS on AA (Table). Results: 76 men with mCRPC treated with first-line AA were included. In multivariate analysis, HSD3B1 (1245 A>C) did not predict response to first-line AA (Table). Conclusions: This hypothesis-generating data shows that inherited variant alleles in HSD3B1 do not predict response to first-line AA in mCRPC. This finding could be due to the ability of AA metabolites to act as both agonist (3-keto-5α-abiraterone) and antagonist (Δ4-abiraterone) on androgen signaling or our small sample size. [Table: see text]

Germline variant in SLCO2B1 and response to abiraterone acetate plus prednisone (AA) in men with metastatic castration-resistant prostate cancer (mCRPC)

311

Background: Currently, there are no predictive biomarkers of response to AA in mCRPC routinely used in the clinic. SLCO2B1 encodes a sodium-independent organic anion transporter that mediates transport of endogenous sex hormones and drugs, including AA, into tissue. Single nucleotide polymorphisms (SNPs) in SLCO2B1 are a validated predictive biomarker of response to androgen deprivation therapy in hormone sensitive prostate cancer. In a recent pre-clinical study, the AA/AG genotype for rs12422149 and the AA genotype for rs1789693 of SLCO2B1 had significantly higher mean tissue abiraterone levels. We hypothesize that the variant allele for rs12422149 and rs1789693 are predictive of improved response to AA in mCRPC. Methods: Clinical data and samples were analyzed from a prospective prostate cancer registry at the University of Utah (Salt Lake City, UT). Genotyping was performed using the Illumina OmniExpress genotyping platform. Primary endpoint was progression-free survival (PFS) on first-line AA in men with mCRPC. We performed pre-specified multivariate Cox regression analyses to assess the independent predictive value of SLCO2B1 rs12422149 and rs1789693 on PFS on AA (table). Results: 76 men with mCRPC treated with first-line AA were included. In a multivariate analysis for rs12422149, a trend towards improved median PFS was seen with the AG genotype (11.2 months) vs. the GG genotype (6.4 months) (HR 0.50, 95% CI 0.24-1.02, p=0.056). No such correlation was seen with rs1789693 genotypes. Conclusions: Consistent with pre-clinical studies, the AG genotype in rs12422149 of SLCO2B1 may be predictive of response to AA in men with mCRPC. This hypothesis-generating data needs further interrogation in larger and independent cohorts. [Table: see text]

Independent assessment of TP53 and PTEN as predictors of response to enzalutamide (ENZ) or abiraterone acetate (AA) in men with metastatic castration-resistant prostate cancer (mCRPC)

351

Background: Alterations in androgen receptor signaling are well-established mechanisms of resistance to medical castration. Pre-clinical studies suggest that alterations to key tumor suppressor genes, such as TP53 or PTEN, may also be associated with development of androgen independence as an alternate mechanism of castration-resistance. Previous studies have shown that TP53 inactivation and PTEN loss are predictive of response to novel androgen axis inhibitors. Here, we independently assess whether TP53 and PTEN genomic alterations are predictive of response to ENZ and AA in men with mCRPC. Methods: Clinical data and samples were analyzed from a prospective prostate cancer registry at the University of Utah (Salt Lake City, UT). Next-generation sequencing (NGS) was performed on predominantly primary tumor tissue for 343 somatic and germline genetic alterations using FoundationOne. Primary endpoints were progression-free survival (PFS) and overall survival (OS). Patients with mCRPC who were treated with any line AA or enzalutamide were included. We performed a univariate analysis to assess the predictive value of TP53 and PTEN. Only patients treated with single-agent therapy were included. Results: Of 141 men with prostate cancer and NGS available, 56 were included. Most patients were treated with abiraterone (n = 50), and only 6 with enzalutamide. 28.6% had PTEN loss and 35.7% had a TP53 mutation. OS and PFS did not differ significantly according to PTEN or TP53 status. Median OS was 40.9 months and not reached for men with and without TP53 mutation (HR 1.85, p = 0.31). Median PFS was 7.5 months and 9.5 months for men with and without TP53 mutation (HR 1.18, p = 0.60). Median PFS was 7.2 months and 9.5 months for men with and without PTEN loss (HR 1.15, p = 0.66). Median OS for PTEN was not mature enough to analyze. Conclusions: In our independent cohort, neither TP53 mutation nor PTEN loss is predictive of response to androgen-directed therapy in men with mCRPC patients. However, this is a relatively small retrospective sample with few events. These results should be considered exploratory only.

Modulator figure of merit for short reach data links

The traditional Mach-Zehnder modulator (MZM) figure of merit (FOM) has been defined as (V_π²)/υ_3dBe, and works effectively for LiNbO₃ long haul modulators. However, for plasma dispersion based electro-optic modulators, or any modulator that has an inherent relationship between its bandwidth, required drive voltage, and optical insertion loss/gain, this FOM is inappropriate. This is particularly true for short reach links with no optical amplification. In the following, we propose a new modulator FOM (M-FOM) based on device metrics that are essential for short-reach links, such as the peak-to-peak drive voltage, modulator rise-fall time, and relative optical modulation amplitude. Link sensitivity measurements from two MZMs that have different bandwidths and optical losses are compared using our M-FOM to demonstrate its utility. Furthermore, we present a novel application protocol of our M-FOM to provide deeper insight into the relative system impact that modulator performance has on data links with no optical amplification, by taking the ratio of M-FOMs from two modulators driven with the same radio frequency drive power.

Incidence and characterization of antiandrogen withdrawal syndrome (AAWS) after enzalutamide (ENZA) in patients (pts) with metastatic castration-refractory prostate cancer (mCRPC)

228

Background: AAWS manifested as PSA decline after discontinuation of first generation AAs, like bicalutamide, has been well characterized and reported. Objective of this study was to assess the incidence and characterize AAWS after ENZA in pts with mCRPC. Methods: From a single institution cohort, pts with mCRPC who discontinued ENZA after documented disease progression per PCWG2 criteria were included. AAWS after ENZA was defined as any degree of PSA decline after discontinuation of ENZA. Baseline pts, disease, and treatment characteristics were compared between Òpts with AAWS after ENZAÓ vs. Òpts without AAWS after ENZAÓ treated during the similar time period: median values were compared with the Wilcoxon rank sum test; proportions were compared with FisherÕs Exact test; and the log rank test was used to compare PFS (Table). Results: 5 pts of 72 eligible pts (~7%) experienced AAWS after discontinuation of ENZA. The levels of PSA decline were as follows: 84%, 32%, 17%, 15% and 15%, respectively. Median AAWS response time, until subsequent PSA progression, was 6 weeks. None of the pts, disease or treatment characteristics (such as prior duration of response to ENZA) were different among Òpts with AAWS after ENZAÓ vs. Òpts without AAWS after ENZAÓ. Conclusions: This is the largest study reporting on the incidence and characterization of AAWS after ENZA. AAWS after ENZA is infrequent (~7%), of short duration (6 weeks), and not predicted by pts, disease or treatment related characteristics. Unlike AAWS after first generation AR inhibitors, like bicalutamide, the AAWS after ENZA is not clinically meaningful and should not have any bearing on the eligibility criteria of clinical trials conducted in the post ENZA setting. [Table: see text]

Efficacy of eplerenone (Epe) in the management of mineralocorticoid excess (MCE) in men with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone (AA) without prednisone (P)

261

Background: AA is approved for Mcrpc with co-administration with P to prevent MCE toxicity such as hypertension, hypokalemia and edema. However, use of P is often not desirable by the relatively asymptomatic patients because of potential for detrimental effects of long term corticosteroid therapy. Epe is a non-steroidal mineralocorticoid antagonist demonstrated to abrogate MCE. Here we report real world experience of use of Epe with AA in men with mCRPC who wished to avoid concomitant P. Methods: Incidence and grade (CTCAE v4) of MCE, along with baseline demographics, disease characteristics, and progression free survival (PFS) in men with mCRPC treated with AA (1000 mg daily), not willing to be treated with P (and thus received treatment with Epe 50 mg daily) were collected retrospectively, and compared with those treated with AA + P (10 mg daily) during the same time period (Table). Continuous variables were assessed by Wilcoxon rank sum or student t-test, and categorical variables were assessed by Fischer’s Exact test or chi-square as appropriate. PFS was compared by Kaplan-Meier. Results: Baseline and disease characteristics, median PFS, and toxicities of all grades were similar in both cohorts (Table). Conclusions: In real world population of men with mCRPC treated with AA, corticosteroids may be avoided by concomitant treatment with Epe. Data need further validation in a larger cohort. [Table: see text]

Association of time from definitive therapy (DT) to start of androgen deprivation therapy (ADT) for metastatic disease and survival outcomes in men with new metastatic hormone-sensitive prostate cancer (mHSPC)

265

Background: Few objective criteria are considered for risk stratification for treatment decision making in men with new mHSPC. Time between DT for localized disease, and start of ADT for new mHSPC may predict response to ADT, and prognosticate outcomes in this setting. Methods: In this multicenter study, men with newly diagnosed mHSPC with prior history of definite therapy for localized prostate cancer were included. Kaplan-Meier and Cox proportional hazard methods assessed time to castration resistance (CRPC) and overall survival (OS) from initiation of ADT, and correlated with the time elapsed from DT to initiation of ADT for new mHSPC. Results: A total of 112 men with new mHSPC initiating ADT, with prior definitive therapy were eligible (all median: age 68 yrs, Gleason score 7, PSA 14 ng/ml, ECOG 0, median time from DT to start of ADT for new mHSPC 54 months). In the univariate analysis, time from DT to start of ADT of < 60 months vs ≥ 60 months significantly correlated with duration of response to ADT and outcomes (Table). After adjustment for Gleason score and log PSA, time from DT to start of ADT for new mHSPC (<60 vs ≥60 months) remained an independent and a significant predictor of time to CRPC (HR 1.92 95% CI 1.02-3.90, p=0.044), and showed trends towards predicting OS (HR 1.77 95% CI 0.60-6.19, p=0.33). Conclusions: Time from DT for localized prostate cancer to initiation of ADT for new mHSPC independently predicts response to ADT, and may aid in risk stratification for treatment decision making in men with new mHSPC. These hypothesis-generating data require validation in a larger cohort. [Table: see text]

Impact of circulating tumor cell (CTC) nucleus size on outcomes with abiraterone acetate (AA) therapy in men with metastatic castration-resistant prostate cancer (mCRPC)

253

Background: CTC enumeration but not CTC morphology has been reported to predict outcomes to treatment in men with mCRPC. Recently Chen JF et. al (Cancer, 2015) showed an association with nuclear size and incidence of visceral disease in metastatic prostate cancer. In this study, we investigate the impact of CTC nucleus size on outcomes in men treated with AA for mCRPC. Methods: In a cohort of men with mCRPC treated with first-line AA, who had CTCs identified by CellSearch (CS) analysis prior to initiating treatment, we retrospectively quantified the nuclear size of CTCs by ImageJ/Fiji 1.46 software and correlated with progression free survival (PFS) on AA. We analyzed with univariate in addition to pre-specified multivariable analysis adjusted for Gleason score and baseline log PSA to assess independent predictive value of CTC nuclear size on PFS. Median PFS was calculated by Kaplan-Meier analysis and p-values were determined from Cox proportional hazards model. Results: 22 men treated with AA for mCRPC were included. Median nucleus size was 23.8 µm. Patients were divided in to 2 cohorts: small nuclear cohort (CTC nucleus size < 23.8 µm) vs large nuclear cohort (CTC nucleus size ≥23.8 µm). There was a non-significant trend towards worsened PFS (5.8 versus 6.8 months) in the larger nuclear size arm (Table). Conclusions: In this cohort of men with CRPC treated with AA, there is a non-significant trend towards decreased PFS associated with larger CTC nucleus size. Data are hypothesis generating and require further interrogation in a larger cohort. [Table: see text]

Independent validation of effect of HSD3B1 genotype on response to androgen deprivation therapy (ADT) in hormone-sensitive prostate cancer (HSPC)

172

Background: A germline inherited polymorphic variant (1245A→C) in the HSD3B1 gene was recently reported to correlate with shorter duration of response to ADT in men with HSPC (Hearn JW, Lancet Oncology, 2016). HSD3B1 gene encodes the enzyme 3β-hydroxysteroid dehydrogenase-1 (3βHSD1), which catalyzes adrenal androgen precursors into dihydrotestosterone, the most potent androgen. Presence of one or more variant alleles was associated with shorter response to ADT compared to those with no variant alleles of this gene. Objective of this study was to validate these results in an independent cohort. Methods: Clinical data and samples were from a prospectively maintained prostate cancer registry at the University of Utah (Salt Lake City, UT). Genotyping was performed as described by Hearn at al. Primary endpoint was progression-free survival on ADT, i.e time to onset of castration resistance. We performed pre-specified multivariate analyses to assess the independent predictive value of HSD3B1 genotype on PFS on ADT (Table). Results: 102 men with new mHSPC met eligibility and included in the analysis. The allelic frequency of the HSD3B1 (1245C) variant in our cohort was 31%, i.e. similar to that reported by Hearn et al. In multivariate analysis, those men in the homozygous variant group had significantly shorter PFS in comparison to those in the homozygous wild type group; no significant difference in PFS was observed in those men in the heterozygous group compared to those in the homozygous wild type group (Table). Conclusions: HSD3B1(1245C) predicted inferior response to ADT in our independent cohort of men with mHSPC. We also confirm that this polymorphism is quite common in this population. [Table: see text]

Genomic diversity between primary tumor tissue and tumor circulating cell-free DNA (cfDNA) in patients (pts) with metastatic prostate cancer

189

Background: Tumor tissue and tumor cfDNA next-generation sequencing (NGS) tests are obtained in pts with metastatic prostate cancer and have demonstrated a diverse genomic landscape. High-level evidence does not exist for utilizing these tests to guide treatment selection in these pts. Targeted therapies are available for metastatic prostate cancer treatment and clinical trials are investigating drugs targeting specific molecular pathways. The objective of this study was to assess type and number of genomic aberrations between tumor tissue and cfDNA. Methods: Pts with metastatic prostate cancer who had both tissue and cfDNA results were selected and genomic profiles were compared between these two technologies. The mean number of tissue mutations was compared to cfDNA mutations for all pts using the t-test. The mutations for both tests were then categorized into five pathways: DNA repair, cell cycle regulation, PI3K, epigenetics, and androgen receptor (AR). For each pathway, the total number of patients with a mutation was compared between tissue and cfDNA using the Mann-Whitney test. Results: Nineteen pts were identified with both tissue and cfDNA results. The mean number of mutations identified was significantly less with cfDNA (95% CI, 2.7-5.3) compared to tissue (95% CI, 7.0-9.7; P < 0.0001). There were significantly more patients with PI3K pathway mutations identified in the tissue compared to cfDNA (73.7% vs 21.1% P = 0.0018), as well as epigenetic mutations (47.4% vs 0.0% P = 0.0012). There was no difference in the number of patients identified to have DNA repair, cell cycle regulation, and AR variances between the two tests. Conclusions: The lower number of aberrations detected by the cfDNA test may have occurred due to lower sensitivity of cfDNA compared to tissue based NGS. Discordance in the type of genomic variances between the two tests suggests intra-individual genetic diversity, and these results may have implications in treatment selection of pts with metastatic prostate cancer. Data are hypothesis generating and need further investigation in a larger cohort.

Intra-individual genomic diversity between circulating tumor cell-free DNA (cfDNA) and tumor tissue testing in metastatic renal cell carcinoma (mRCC)

444

Background: Multiple approved targeted therapies are available for treatment of mRCC. Though some clinical trials guide treatment selection, there are many gaps without high-level evidence. Both tumor tissue and cfDNA based next-generation sequencing (NGS) testing are frequently performed to help guide treatment. Our objective was to assess type and number of genomic aberrations among tumor tissue and cfDNA. Methods: 14 sequential pts with both tissue and cfDNA NGS testing were selected and genomic profiles were compared. The total number of aberrations detected was statistically evaluated using comparison of the means. The Mann-Whitney test was used to compare the incidence of mutations in identified mutation pathways. Results: There was a discordance in the genetic aberrations detected among tumor versus cfDNA NGS tests, confirming intra-individual genetic diversity. Specifically, alterations in the DNA repair, PI3K, and epigenetic pathways were more common in tissue based testing (Table). Additionally, the median number of mutations identified was significantly lower for cfDNA based NGS testing (median 1.5) compared to tissue based NSG testing (median 10.0) (p < 0.0001). Conclusions: Discordance in the type of genomic aberrations in tissue versus cfDNA testing suggests intra-individual genetic diversity and may have implications in treatment selection when using these tests. Lower number of aberrations detected by the cfDNA testing may have occurred due to lower sensitivity of NGS by cfDNA compared to the tissue based NGS. The higher frequency of aberrations on tissue based testing suggests that tissue based testing should be used preferentially in clinical trials and practice. This data is hypothesis generating and needs further investigation in a larger cohort. [Table: see text]

Distributed electrode Mach-Zehnder modulator with double-pass phase shifters and integrated inductors

A novel high-speed Mach-Zehnder modulator (MZM) fully integrated into a 90 nm CMOS process is presented. The MZM features 'double-pass' optical phase shifter segments, and the first use of integrated inductors in a 'velocity-matched' distributed-electrode configuration.

Toxins which activate adenylate cyclase

Cholera toxin and other heat-labile enterotoxins have the same subunit structure (A5B) and all catalyse the mono ADP-ribosylation of Ns, a regulator of adenylate cyclase, probably at an arginine residue. They also ADP-ribosylate a variety of other membrane and soluble proteins at much slower rates. The rates differ from protein to protein but it may be that every arginine residue in every protein is ADP-ribosylated at some slow rate. A guanine nucleotide triphosphate is required for the ADP-ribosylation of the major (Ns) and minor substrates alike. It used to be thought that all the substrates were GTP-binding proteins but this cannot be so. Rather, the GTP is required because it has to bind to some additional site on the membrane, termed 'S', in a cooperative event that involves a soluble protein called cytosolic factor (CF). If we expose erythrocyte membranes to CF and the GTP analogue Gpp(NH)p we can later extract in detergent a factor or complex that confers upon naive erythrocyte membranes the ability to be ADP-ribosylated. Pertussis toxin also has an A5B structure and acts on an intracellular substrate for ADP-ribosylation, namely the negative regulator of adenylate cyclase, called Ni. ADP-ribosylation prevents the reduction of cyclase activity by inhibitory hormones. The ADP-ribosylation of Ns or Ni does not affect the rate of ADP-ribosylation of the other protein.

ADP-ribosylation of p21ras and related proteins by Pseudomonas aeruginosa exoenzyme S

Pseudomonas aeruginosa exoenzyme S ADP-ribosylates p21ras and several related proteins. ADP-ribosylation of p21ras does not alter interactions with guanine nucleotides. The ras-related GTP-binding proteins, including Rab3, Rab4, Ral, Rap1A, and Rap2, are also substrates; given these results, we propose a model for the role of exoenzyme S in pathogenesis.

Characterization of the C3 gene of Clostridium botulinum types C and D and its expression in Escherichia coli

Clostridium botulinum type C and D strains produce exoenzyme C3, which ADP-ribosylates the Rho protein, a 21-kDa regulatory GTP-binding protein. In a previous work, we demonstrated that the C3 gene is encoded by bacteriophages C and D of C. botulinum by using DNA-DNA hybridizations with oligonucleotides deduced from the C3 protein N-terminal sequence. The C3 coding gene was cloned and sequenced, but its upstream DNA region could not be studied because of its instability in Escherichia coli. In this work, the upstream DNA region of the C3 gene was directly amplified by the polymerase chain reaction and sequenced. The C3 gene encodes a polypeptide of 251 amino acids (27,823 Da) consisting of a 40-amino-acid signal peptide and a mature protein of 211 amino acids (23,546 Da). The C3 mature protein was expressed in E. coli under the control of the trc promoter. The recombinant polypeptide obtained was recognized by C3 antibodies and ADP-ribosylated the Rho protein. The C3 gene nucleotide sequence is identical on C and D phage DNAs. At the amino acid sequence level, no similarity was found among C3, other ADP-ribosylating toxins, or tetanus or botulinal A, C1, and D neurotoxins.

Pseudomonas aeruginosa exoenzyme S requires a eukaryotic protein for ADP-ribosyltransferase activity

Pseudomonas aeruginosa exoenzyme S ADP-ribosylates several GTP-binding proteins of apparent Mr = 23,000-25,000. Exoenzyme S absolutely requires a soluble eukaryotic protein, which we have named FAS (Factor Activating exoenzyme S), in order to ADP-ribosylate all substrates. The rate of ADP-ribosylation of all exoenzyme S substrates increases linearly with time and with the FAS concentration. FAS is wide-spread in eukaryotes but appears to be absent from prokaryotes. We have estimated the molecular mass of the protein to be approximately 29,000 daltons and its pI to be 4.3-4.5. Several bacterial toxins share this sort of requirement for the presence of a eukaryotic protein for enzymic activity. In particular, FAS resembles ADP-ribosylation factor, a 21,000-dalton GTP-binding protein which performs an analogous function for cholera toxin. However, we can find no evidence that FAS binds GTP. In the presence of FAS, exoenzyme S ADP-ribosylates several proteins in lysates of P. aeruginosa. The requirement for a eukaryotic protein for enzymic activity, which is common to several bacterial toxins, may be a device to identify the eukaryotic environment and to ensure that the enzymes cannot function within and harm the toxin-producing bacteria.

The zinc fingers of human poly(ADP-ribose) polymerase are differentially required for the recognition of DNA breaks and nicks and the consequent enzyme activation. Other structures recognize intact DNA

The recognition of double-stranded DNA breaks and single-stranded nicks by human poly(ADP-ribose) polymerase and the consequent enzymic activation were examined using derivatives of the enzyme expressed in Escherichia coli. The N-terminal 162 residues encompass two zinc fingers. Deletion or mutation of the first finger results in a loss of activation by DNA with either single-stranded or double-stranded damage. Destruction of the second finger reduces activation by double-stranded DNA breaks only slightly, but eliminates activation by single-stranded DNA nicks. These data suggest that activation by single-stranded DNA nicks requires two zinc fingers, but activation by double-stranded DNA breaks requires only the finger closer to the N terminus. Variant proteins that lack both zinc fingers are enzymically inactive but still exhibit weak DNA binding, which is independent of DNA damage. Thus, other regions are also capable of binding intact DNA, but the recognition of a strand nick or break which occasions the synthesis of poly(ADP-ribose) specifically requires the zinc fingers.

Speech Sounds Perception Test: nonrandom response locations form a logical fallacy in structure

The response format of the Speech Sounds Perception Test confounds speech perception with irrelevant method variance. To rectify this problem the response format was revised by randomizing the response locations. An empirical comparison of the revised and original forms was undertaken with forensic (n=59) and psychiatric (n=67) samples. The empirical results coupled with the logical problem in the original form indicates that a revision is necessary.

Several GTP-binding proteins, including p21c-H-ras, are preferred substrates of Pseudomonas aeruginosa exoenzyme S

Pseudomonas aeruginosa exoenzyme S has appeared to be relatively indiscriminate in its choice of substrates, but in fact it ADP-ribosylates only a small subset of cellular proteins and exhibits a marked preference for several different membrane-associated proteins of apparent Mr = 23,000-25,000, at least some of which appear to bind GTP. One of these is the p21 product of the proto-oncogene c-H-ras, which can be labeled to completion. ADP-ribosylation does not alter the interaction of p21c-H-ras with guanyl nucleotides, but does cause a shift in electrophoretic mobility that implies a large conformational change. Exoenzyme S modifies all of its substrates at arginine residues.

The mammalian G protein rhoC is ADP-ribosylated by Clostridium botulinum exoenzyme C3 and affects actin microfilaments in Vero cells

Clostridium botulinum C3 is a recently discovered exoenzyme that ADP-ribosylates a eukaryotic GTP-binding protein of the ras superfamily. We show now that the bacterially-expressed product of the human rhoC gene is ADP-ribosylated by C3 and corresponds in size, charge and behavior to the dominant C3 substrate of eukaryotic cells. C3 treatment of Vero cells results in the disappearance of microfilaments and in actinomorphic shape changes without any apparent direct effect upon actin. Thus the ADP-ribosylation of a rho protein seems to be responsible for microfilament disassembly and we infer that the unmodified form of a rho protein may be involved in cytoskeletal control.

Exoenzyme S of Pseudomonas aeruginosa ADP-ribosylates the intermediate filament protein vimentin

Exoenzyme S, which had been thought to be unselective, catalyzes the ADP-ribosylation of only a subset of cellular proteins. The intermediate filament protein vimentin is one of the more abundant substrates. Disassembled vimentin, and proteolytic fragments of vimentin that cannot form filaments, is more readily ADP-ribosylated than is filamentous vimentin.

Actin-specific ADP-ribosyltransferase produced by a Clostridium difficile strain

By screening possible ADP-ribosyltransferase activities in culture supernatants from various Clostridium species, we have found one Clostridium difficile strain (CD196) (isolated in our laboratory) that is able to produce, in addition to toxins A and B, a new ADP-ribosyltransferase that was shown to covalently modify cell actin as Clostridium botulinum C2 or Clostridium perfringens E iota toxins do. The molecular weight of the CD196 ADP-ribosyltransferase (CDT) was determined to be 43 kilodaltons, and its isoelectric point was 7.8. No cytotoxic activity on Vero cells or lethal activity upon injection in mice was associated with this enzyme. CDT was neither related to C. difficile A or B toxins nor to C. botulinum C2 toxin component I. However, Vero cells cultivated in the presence of C. difficile B toxin had a lower amount of actin able to be ADP-ribosylated by CDT or C2 toxin in vitro. Antibodies raised against CDT reacted by immunoblot analysis with a 43-kilodalton protein of C. perfringens type E culture supernatant producing the iota toxin.