Early Detection Of Treatment Failure Research Articles

Management of spontaneous pyogenic spondylodiscitis: a descriptive cohort study

BackgroundSpontaneous spondylodiscitis (SD) is an inflammation of the vertebral endplate and the intervertebral disc with no prior surgery or intervention. The treatment of spontaneous pyogenic SD mainly consists of systemic antibiotics and rest. Some cases require surgery due to failure of medical treatment or due to neurological compromise. Due to the disease heterogeneity, there are no standardized, widely adopted treatment protocols. We conducted this study to assess the clinical outcome of the different treatment modalities.ResultsThis is a retrospective analysis of prospectively collected data of patients with spontaneous non-tuberculous spondylodiscitis. Thirty-eight patients were identified, including 14 males and 24 females. The mean age was 49 years. Twenty-three patients underwent surgery from the start while 15 patients received conservative medical treatment. Among the latter, 8 patients showed disease progression and required surgical intervention. The ODI/NDI at 1 year (mean = 8) was significantly better than before treatment (mean = 18). Among 11 patients with motor deficit at presentation, 8 improved and 3 remained stable. There were 14 complications, including 11 minor and 3 major, requiring one revision surgery.ConclusionsSurgical decompression and debridement with or without instrumented fusion for complicated SD cases is a safe and effective treatment modality. Close follow-up is needed in case of conservative treatment for early detection of treatment failure and disease progression. Baseline characteristic variabilities in patients with spontaneous pyogenic SD could predict conservative treatment failure, but this needs to be validated in larger series.

Can TTMV clearance predict recurrence in HPV HNSCC?

6066 Background: Patients with locally advanced (LA) HPV HNSCC are treated with various types of induction chemotherapy (IC) followed by standard (sd) or reduced (rd) chemoradiation (CRT). Tumor tissue-modified viral HPV DNA (TTMV) pairs with PET-CT in predicting an early detection of treatment failure in HPV-related HNSCC. Mid-treatment TTMV assessment in HPV-related HNSCC can help identify patients who are eligible to receive a lower dose of IC and/or CRT or those who may require close follow-up. Methods: Patients with LA HPV+ HNSCC with high-risk features (radiographic ECE, T4 primary, >N2c) and <20 pack-year (py) smoking history were treated with IC followed by rdCRT (56 Gy); sdCRT (70 Gy) was used in non-responders. 16/23 received IC with TPF, 1/23 TP, and 6/23 TP-PD1, and all patients received carboplatin weekly with their CRT. Regeneron trial patients who received TP-Cemiplimab (PD1) IC followed by sdCRT are also continuing adjuvant Cemiplimab alone for 6 months (NCT05376553). PET-CT-confirmed residual, recurrent, or metastatic diseases were defined as treatment failures; TTMV + patients only if PET-CT confirmed. Results: 23 subjects treated with IC followed by CRT between 2/4/21-1/26/24, who had pre- and post-treatment TTMV were included in our analysis. The median pre-IC TTMV was 8082 (27 – 90770). The median follow-up time from treatment start was 21 months. 9/23 patients had full clearance TTMV after 1 cycle of IC defined as rapid responders (RR). 11/23 patients still had positive TTMV after 1st cycle of IC were defined as slow responders (SR). 1 patient had no TTMV done after 1 cycle of IC but was elevated after 2nd IC; he was defined as SR. 2 patients had a positive pre-IC TTMV, but no TTMV was drawn during IC to see if RR. 1 of 2 patients was TTMV negative prior to CRT, and 2/2 had a 1st post IC negative TTMV done 1 week after CRT started. They were both included in the analysis but defined as unknown response status. TTMV testing was done for all 23 subjects after CRT; all were negative. All subjects have TTMV testing done during their surveillance visits. Among 9/23 RR, none developed a failure. Among 12/23 SR, 3 patients developed a failure: 1/3 was TTMV+ but PET-, being followed with TTMV and PET-CT; and 2/3 were confirmed failures, TTMV+ and PET+; 1 locoregional, 1 metastatic. 2 patients were not known to be a SR or RR and had no recurrence. Among 23 patients, NPV of TTMV to detect failure was 100%, but PPV was 96% (1/23). Conclusions: IC followed in rapid clearance of TTMV in 39% of patients, and all remained disease-free. 3/11 (27%) with persistently elevated TTMV after cycle 1 relapsed as of this time point. This small study was not large enough to be practice-changing. However, this is significantly hypothesis-generating and should be tested in a larger trial to help identify patients for de-escalation (RR) or closer surveillance (SR).

Revolutionizing HIV-1 Viral Load Monitoring in India: The Potential of Dried Blood Spot Analysis for Expanding Access and Improving Care.

India continues to grapple with a significant burden of HIV infections. Despite notable progress in prevention and treatment efforts, multiple challenges, such as high-risk populations, inadequate testing facilities, and limited access to healthcare in remote areas, persist. Though the Government of India offers HIV-1 plasma viral load testing at various medical centers, aiding treatment decisions and monitoring antiretroviral therapy effectiveness, enhancing care for individuals living with HIV under the National AIDS Control Program (NACP), the nation's large population and diverse demographics further complicate its outreach and response. Hence, strategic interventions and alternative methods of testing remain crucial to curbing HIV transmission and improving the quality of life for those affected. Dried blood spot (DBS) sampling has emerged as a convenient and cost-effective alternative for HIV-1 viral load testing, revolutionizing the landscape of diagnostic and monitoring strategies for HIV infection. Though the plasma-based viral load remains the gold standard for monitoring HIV-1, DBS-based HIV-1 viral load testing holds immense promise for improving access to care, particularly in resource-limited settings where traditional plasma-based methods may be logistically challenging. DBS entails the collection of a small volume of blood onto filter paper, followed by drying and storage. This approach offers numerous advantages, including simplified sample collection, transportation, and storage, reducing the need for cold-chain logistics. Recent studies have demonstrated the feasibility and accuracy of DBS-based HIV-1 viral load testing, revealing a strong correlation between DBS and plasma measurements. Its implementation can enhance the early detection of treatment failure, guide therapeutic decisions, and ultimately contribute to better clinical outcomes for HIV-infected individuals. Hence, this review explores the principles, advancements, feasibility, and implications of DBS-based HIV-1 viral load testing.

Current ARTs, Virologic Failure, and Implications for AIDS Management: A Systematic Review.

Antiretroviral therapies (ARTs) have revolutionized the management of human immunodeficiency virus (HIV) infection, significantly improved patient outcomes, and reduced the mortality rate and incidence of acquired immunodeficiency syndrome (AIDS). However, despite the remarkable efficacy of ART, virologic failure remains a challenge in the long-term management of HIV-infected individuals. Virologic failure refers to the persistent detectable viral load in patients receiving ART, indicating an incomplete suppression of HIV replication. It can occur due to various factors, including poor medication adherence, drug resistance, suboptimal drug concentrations, drug interactions, and viral factors such as the emergence of drug-resistant strains. In recent years, extensive efforts have been made to understand and address virologic failure in order to optimize treatment outcomes. Strategies to prevent and manage virologic failure include improving treatment adherence through patient education, counselling, and supportive interventions. In addition, the regular monitoring of viral load and resistance testing enables the early detection of treatment failure and facilitates timely adjustments in ART regimens. Thus, the development of novel antiretroviral agents with improved potency, tolerability, and resistance profiles offers new options for patients experiencing virologic failure. However, new treatment options would also face virologic failure if not managed appropriately. A solution to virologic failure requires a comprehensive approach that combines individualized patient care, robust monitoring, and access to a range of antiretroviral drugs.

Dynamic Contrast-Enhanced MR Perfusion: Role in Diagnosis and Treatment Follow-Up in Patients with Vertebral Body Tumors.

Recent therapeutic advances have led to increased survival times for patients with metastatic disease. Key to survival is early diagnosis and subsequent treatment as well as early detection of treatment failure allowing for therapy modifications. Conventional MR imaging techniques of the spine can be at times suboptimal for identifying viable tumor, as structural changes and imaging characteristics may not differ pretreatment and posttreatment. Advanced imaging techniques such as DCE-MRI can allow earlier and more accurate noninvasive assessment of viable disease by characterizing physiologic changes and tumor microvasculature.

Plasma IL13Rα2 as a novel liquid biopsy biomarker for glioblastoma.

Glioblastoma (GBM) is the most common and deadliest brain tumor with unrelenting and rapid disease progression. The standard of care for GBM is surgical excision followed by radiation with concurrent and adjuvant temozolomide-centered chemotherapy (TMZ). Treatment failure and resistance is the rule and despite advances in imaging technology, early detection of treatment failure or impending resistance remains a challenge. There is a dire, unmet, need in clinical practice for minimally-invasive diagnostic tools to enable timely understanding of disease progression and treatment response. Here, we aim to address this clinical need by leveraging a unique characteristic of GBM: the overexpression of the α2 variant of the IL-13 receptor in over 75% of GBM tumors. In this study we examined patients with primary GBM from Penn State and Cleveland Clinic compared to healthy controls. IL13Rα2 was detectable in plasma of GBM patients using ELISA but detection could be optimized by PEG precipitation to enrich for extracellular vesicles (EVs). Patients with GBM had elevated levels of plasma IL13Rα2, which correlated to levels of this receptor in the tumor tissue. Elevated plasma levels of IL13Rα2 predicted longer overall survival (OS) (19.8 vs. 13.2 months). Similarly, detection of IL13Rα2 + cells in tumor tissue also predicted longer OS (22.1 vs. 12.2 months). These findings strongly suggest that expression of the IL13Rα2 receptor confer survival advantage in GBM patients, which can be determined through a minimally-invasive liquid biopsy. Detection of plasma IL13Rα2 can also be used to select GBM patients for targeted tumor therapy.

Circulating Tumor DNA Monitoring Reveals Molecular Progression before Radiologic Progression in a Real-life Cohort of Patients with Advanced Non-small Cell Lung Cancer.

The clinical potential of liquid biopsy in patients with advanced cancer is real-time monitoring for early detection of treatment failure. Our study aimed to investigate the clinical validity of circulating tumor DNA (ctDNA) treatment monitoring in a real-life cohort of patients with advanced non-small cell lung cancer (NSCLC). Patients with advanced or noncurative locally advanced NSCLC were prospectively included in an exploratory study (NCT03512847). Selected cancer-specific mutations were measured in plasma by standard or uniquely designed droplet digital PCR assays before every treatment cycle during first-line treatment until progressive disease (PD). Correlation between an increase in ctDNA (= molecular progression) and radiologic PD was investigated, defined as lead time, and the corresponding numbers of likely futile treatment cycles were determined. Utility of ctDNA measurements in clarifying the results of nonconclusive radiologic evaluation scans was evaluated. Cancer-specific mutations and longitudinal plasma sampling were present in 132 of 150 patients. ctDNA was detectable in 88 (67%) of 132 patients treated by respectively chemotherapy (n = 41), immunotherapy (n = 43), or combination treatment (n = 4). In 66 (90%) of 73 patients experiencing PD, a ctDNA increase was observed with a median lead time of 1.5 months before radiologic PD. Overall, 119 (33%) of 365 treatment cycles were administered after molecular progression. In addition, ctDNA measurements could clarify the results in 38 (79%) of 48 nonconclusive radiologic evaluations. ctDNA monitoring leads to earlier detection of treatment failure, and clarifies the majority of nonconclusive radiologic evaluations, giving the potential of sparing patients from likely futile treatments and needless adverse events. Treatment monitoring by ctDNA has the clinical potential to reveal PD before radiologic evaluation and consequently spare patients with advanced cancer from likely ineffective, costly cancer treatments and adverse events.

Regenerative endodontic therapy for external inflammatory lateral resorption following traumatic dental injuries: Evidence assessment of best practices.

External inflammatory lateral resorption (EILR) following dental trauma is a severe complication that can lead to significant root loss and tooth extraction. The aim of this project was to review current evidence in the literature on regenerative endodontic therapy (RET) for EILR following traumatic injuries and assess the best treatment practices. Publications appearing in PubMed, from January 1, 2001 to January 9, 2022 were studied. Inclusion criteria were: (a) Publications in English; (b) Publications on RET and EILR; (c) Teeth subjected to dental trauma; and (d) Presence of intracanal bleeding and blood clots. Exclusion criteria were: (a) Conference proceedings; (b) Lectures; (c) Abstracts; and (d) Letters to editor; (e) Non-English publications. 355 publications were analysed. Nine met all inclusion criteria. In 10 (58.8%) teeth, triple antibiotic paste was used for an average of 26 days. Double antibiotic paste was used in 3 (17.6%) teeth for an average of 14 days. In 3 (17.6%) cases, calcium hydroxide (Ca(OH)2 ) was used for 14 days and negative pressure irrigation was applied once on 1 (6%) tooth. Using RET to treat EILR has some advantages compared to long term CA(OH)2 dressing. RET requires shorter dressing time compared to CA(OH)2 . This can significantly improve patient compliance. Additionally, in immature teeth, RET helps to arrest root resorption leading to continued root maturogenesis and revascularization. It is recommended that a meticulous follow-up should be conducted when RET is performed to assure early detection of treatment failure. RET appears to be a good treatment modality producing biologic repair and improving prognosis in cases of EILR in post-traumatic tooth/pulp injuries. The key limitation of this study is that all publications included were either case reports or case series that usually tend to report successful outcome.

Plasma-derived exosomes as biomarkers for therapy monitoring in head and neck cancer patients treated with surgery and (chemo)radiotherapy

Abstract Background Head and neck squamous cell carcinomas (HNSCC) are highly immunosuppressive and aggressive malignancies. Exosomes are small extracellular vesicles that mediate intercellular communication. HNSCC patients have a significantly higher exosome load compared to healthy donors. Here, we evaluated the potential of plasma-derived exosomes as biomarkers for therapy monitoring in advanced HNSCC treated with conventional therapy. Methods Plasma from 17 HNSCC patients was collected before, during, and after treatment by surgery with adjuvant (chemo)radiation and at time of recurrence. Total exosomal protein (TEP) of exosomes was measured to estimate exosome load. Flow cytometry was used to evaluate relative fluorescence intensity (RFI) of tumor-associated and immunoregulatory proteins on exosomes. Effects of exosomes on CD8+ T cells and adenosine production by CD39+ T cells was assessed by flow cytometry and mass spectrometry. Results TEP levels and tumor-derived exosomes varied during and after therapy with an overall decrease in the tumor-free follow up but with an increase at time of recurrence. RFI values of immune checkpoints on exosomes, their potential for T cell inhibition, and adenosine production changed during and after therapy. Recurrent patients showed a different immunoinhibitory profile compared to disease-free patients. Exosomal PD-L1 emerged as the earliest discriminator for treatment failure and disease-free survival. Conclusions Plasma-derived exosomes from HNSCC patients emerge as promising non-invasive biomarkers for early detection of treatment failure. These exosomes can accurately inform about changes in patients’ immune status and may alert of impeding recurrence.

Changes in circulating exosome molecular profiles following surgery/(chemo)radiotherapy: early detection of response in head and neck cancer patients

BackgroundHead and neck cancers (HNSCC) are highly immunosuppressive. Plasma-derived exosomes of HNSCC patients carry immunomodulatory molecules, and their cargo correlates with clinical parameters. Here, we evaluated the exosomal molecular profile for early detection of treatment failure in locally advanced HNSCC patients treated with conventional therapy.MethodsPlasma from 17 HNSCC patients was collected before, during, and after treatment by surgery with adjuvant (chemo)radiation and at recurrence. Exosomes were isolated by size-exclusion chromatography. Total exosomal protein (TEP) was used to estimate exosome load and on-bead flow cytometry to evaluate relative fluorescence intensity (RFI) of tumour-associated and immunoregulatory proteins on exosomes. Exosomal effects on the activity of and adenosine production by T cells was assessed by flow cytometry and mass spectrometry.ResultsTEP and the ratio of tumour-/immune-cell-derived exosomes varied during and after therapy with an overall decrease in the tumour-free follow-up but an increase at recurrence. RFI values of immunoregulatory proteins on exosomes, their ability for T cell inhibition and adenosine production changed during and after therapy. PD-L1 was the earliest discriminator for treatment failure and disease-free survival.ConclusionsMonitoring of plasma exosomes during therapy represents a promising opportunity for early detection of treatment failure and risk stratification to delay/avoid recurrence.

Virologic response of treatment experienced HIV-infected Ugandan children and adolescents on NNRTI based first-line regimen, previously monitored without viral load

BackgroundMany HIV-infected African children gained access to antiretroviral treatment (ART) through expansion of PEPFAR programs since 2004 and introduction of “Test and Treat” WHO guidelines in 2015. As ART access increases and children transition from adolescence to adulthood, treatment failure is inevitable. Viral load (VL) monitoring in Uganda was introduced in 2016 replacing clinical monitoring. However, there’s limited data on the comparative effectiveness of these two strategies among HIV-infected children in resource-limited settings (RLS).MethodsHIV-infected Ugandan children aged 1–12 years from HIV-care programs with > 1 year of first-line ART using only immunologic and clinical criteria to monitor response to treatment were screened in 2010. Eligible children were stratified by VL ≤ 400 and > 400 copies/ml randomized to clinical and immunological (control) versus clinical, immunological and VL monitoring to determine treatment failure with follow-up at 12, 24, 36, and 48 weeks. Plasma VL was analyzed retrospectively for controls. Mixed-effects logistic regression models were used to compare the prevalence of viral suppression between study arms and identify factors associated with viral suppression.ResultsAt baseline all children (n = 142) were on NNRTI based ART (75% Nevirapine, 25% efavirenz). One third of ART-experienced children had detectable VL at baseline despite high CD4%. Median age was 6 years (interquartile range [IQR]: 5–9) and 43% were female. Overall, the odds of viral suppression were not different between study arms: (arm by week interaction, p = 0.63), adjusted odds ratio [aOR]: 1.07; 95%CI: 0.53, 2.17, p = 0.57) and did not change over time (aOR: 0 vs 24 week: 1.15; 95% CI: 0.91, 1.46, p = 0.24 and 0 vs 48 weeks: 1.26; 95%CI: 0.92, 1.74, p = 0.15). Longer duration of a child’s ART exposure was associated with lower odds of viral suppression (aOR: 0.61; 95% CI: 0.42, 0.87, p < .01). Only 13% (9/71) of children with virologic failure were switched to second-line ART, in spite of access to real-time VL.ConclusionWith increasing ART exposure, viral load monitoring is critical for early detection of treatment failure in RLS. Clinicians need to make timely informed decisions to switch failing children to second-line ART.Trial registrationClinicalTrials.gov NCT04489953, 28 Jul 2020. Retrospectively registered. (https://register.clinicaltrials.gov).

Molecular response to imatinib in patients with chronic myeloid leukemia in Tanzania

Imatinib is the mainstay of treatment of patients with chronic myeloid leukemia (CML) in Tanzania. Monitoring molecular response to therapy by real-time polymerase chain reaction at defined milestones is necessary for early detection of treatment failure. However, this assay is not routinely performed in Tanzania; therefore, the depth of molecular response among patients with CML is not known. A total of 158 patients with previously diagnosed CML who received imatinib treatment were recruited from January 2019 and followed up through October 2020 at Ocean Road Cancer Institute. Information was obtained at the time of diagnosis and follow-up. Blood samples were collected in EDTA tubes to measure the BCR/ABL ratio on the Gene Xpert system for molecular response determination. The median age of the 158 adult patients was 45 years (range, 18-86). By reference to established treatment milestones, only 37 (23.4%) achieved optimal molecular response. Signs of advanced-stage disease, in particular the need for red cell transfusions before diagnosis (adjusted odds ratio [AOR], 3.4; 95% CI, 1.32-9.17) and cytopenias (AOR, 2.26; 95% CI, 1.03-4.96) necessitating drug interruptions were statistically validated predictors of treatment failure on multivariate, multinomial logistic regression. Patient survival at the 22-month follow-up was lowest, with 78.6% (95% CI, 69.4-85.4) in the failure-to-respond category and highest in patients achieving optimal response 97.0% (95% CI, 80.9-99.6). In summary, the majority of patients with CML treated with imatinib in Tanzania do not obtain deep molecular response. This outcome can be attributed to late diagnosis, the development of cytopenias requiring multiple drug interruptions, and poor adherence to treatment.

Molecular detection of 7SL-derived small RNA is a promising alternative for trypanosomosis diagnosis.

Equine trypanosomosis comprises different parasitic diseases caused by protozoa of the subgenus Trypanozoon: Trypanosoma equiperdum (causative agent of dourine), Trypanosoma brucei (nagana) and Trypanosoma evansi (surra). Due to the absence of a vaccine and the lack of efficacy of the few available drugs, these diseases represent a major health and economic problem for international equine trade. Development of affordable, sensitive and specific diagnostic tests is therefore crucial to ensure the control of these diseases. Recently, it has been shown that a small RNA derived from the 7SL gene (7SL-sRNA) is produced in high concentrations in sera of cattle infected with Trypanosoma congolense, Trypanosoma vivax and Trypanosoma brucei. Our objective was to determine whether 7SL-sRNA could serve as a marker of active infection in equids experimentally infected with Trypanosoma equiperdum by analysing the sensitivity, specificity and stability of the 7SL-sRNA. Using a two-step RT-qPCR, we were able to detect the presence of 7SL-sRNA between 2 and 7days post-infection, whereas seroconversion was detected by complement fixation test between 5 and 14days post-infection. There was a rapid loss of 7SL-sRNA signal from the blood of infected animals one day post-trypanocide treatment. The 7SL-sRNA RT-qPCR allowed an early detection of a treatment failure revealed by glucocorticoid-induced immunosuppression. In addition, the 7SL-sRNA remains detectable in positive sera after 7days of storage at either 4°C, room temperature or 30°C, suggesting that there is no need to refrigerate serum samples before analysis. Our findings demonstrate continual detection of 7SL-sRNA over an extended period of experimental infection, with signals detected more than six weeks after inoculation. The detection of a strong and consistent 7SL-sRNA signal even during subpatent parasitemia and the early detection of treatment failure highlight the very promising nature of this new diagnostic method.

Usefulness of real-time PCR during follow-up of patients treated with Benznidazole for chronic Chagas disease: Experience in two referral centers in Barcelona.

BackgroundAntitrypanosomal treatment with Benznidazole (BZ) or Nifurtimox may be recommended for patients with chronic Chagas disease (CD) to reduce the onset or progression of symptoms. However, such treatment has limited efficacy and high level of toxic effects. In addition, the current cure biomarker (serology conversion) precludes any treatment assessment unless a prolonged follow-up is arranged. PCR is thus the most useful, alternative surrogate marker for evaluating responses to treatment.The aim of this study is to describe the usefulness of real-time PCR in monitoring BZ treatment within a large cohort of chronic CD cases in Barcelona.Methodology/Principal findingsA total of 370 chronic CD patients were monitored with real-time PCR post-BZ treatment. The median follow-up was 4 years (IQR 2.2–5.3y), with a median of 3 clinical visits (IQR 2–4). Only 8 patients (2.2%) presented with at least one incident of positive real-time PCR after treatment and were therefore considered as treatment failure. Four of those failure patients had completed full course treatment, whereas the remaining cases had defaulted with a statistical difference between both groups (p = 0.02). Half of the failure patients had undergone less than 4 years of follow-up monitoring all presented with parasitemia before treatment.Conclusions/SignificanceBZ treatment failure was highly infrequent in our cohort. BZ discontinuation was a risk factor for positive real-time PCR results during clinical follow-up. Regular testing with real-time PCR during follow-up allows for early detection of treatment failure in patients with chronic CD.

Virologic Failure and its Determinant Factors among Children in First Line on Highly Active Anti Retroviral Therapy at Felegehiwot Referral Hospital, Bahir Dar, Northwest, Ethiopia: cross-sectional study

Introduction: Highly active antiretroviral therapy (HAART) played a critical role in the medical management of HIV infected individuals by restoring the immune function and minimizes HIV related outcomes. But treatment failure minimized these advantages and leads to an increment of morbidity and mortality with poor quality of life in all HIV patients. The aim at this study was to assess the prevalence of HIV-1 treatment failure and its determinants factors among children on first line HAART at Felegehiwot Referral Hospital. Methods: Cross sectional study was conducted on 238 children who had on first line HAART regimen using the inclusion criteria. Data were collected from patients’ chart starting from ART commencement (baseline data and other information) and interviewed using structured questionnaire. CD4 T-cells from whole blood and viral load from separated plasma were analyzed according to protocols. The collected data were analyzed using SPSS packages version 20. Descriptive statistics, odds ratio, bi-variate and multiple logistic regression analysis were used to show determinant factors association. Independent associations were considered with p&lt;0.05. Result: Among the 238 participants enrolled, 137(57.6%) were females. The mean ages were 8.09 years and the median months on HAART from initiation were 51.93 months. A total of 25 (10.5%) participants were found to have virologic/treatment failure. The mean CD4 T-cells at base line were 342.33 cells/ml and 672.13 cells/ml respectively. Long duration on treatment, sub-optimal drug adherence, conducting faith healing, high medication dosage and ambulatory functional status at baseline were found to be significant predictors of treatment failure and showed positive odds ratio. Conclusion: This study demonstrates high virologic failure and the determinant factors of virologic failures among HAART first line children are still changing. Therefore, evidence-based intervention and early detection of treatment failure must be made to further identify the potential causes and set standardized protective mechanisms of virologic failures.

Comparison of the Mycobacterium tuberculosis molecular bacterial load assay, microscopy and GeneXpert versus liquid culture for viable bacterial load quantification before and after starting pulmonary tuberculosis treatment

Molecular bacterial load assay (MBLA) rapidly quantifies viable Mycobacterium tuberculosis (Mtb) and may be useful for monitoring treatment response and treatment efficacy.We conducted a prospective study in 56 adults with pulmonary tuberculosis from whom 244 sputum samples were collected before and during the first month of treatment. We evaluated MBLA for early monitoring of bacterial burden and investigated bactericidal activities of first-line therapy in patients infected with drug susceptible and resistant isolates.Mtb loads measured by MBLA and culture were correlated after one-week (r = 0.56) and one-month (r = 0.73) of treatment. Correlations between culture and GeneXpert or microscopy were weaker during treatment. Mtb load by MBLA declined more rapidly than GeneXpert after one-week (2.73 Ct, P < 0.001; 0.95 Ct, P = 0.297, respectively) and one-month (8.94 Ct, P < 0.001; 6.78 Ct, P < 0.001). Mtb loads in multidrug resistant (MDR) infections were significantly greater than in both sensitive and poly/mono-resistance after one-week (P < 0.02) and one-month treatment (P = 0.001).MBLA performed better than GeneXpert and microscopy in comparison to culture for quantifying viable Mtb during treatment. It can be used for monitoring bacterial load during TB treatment, facilitating early detection of treatment failure thus improving outcomes.

Magnitude of Virological Treatment Failure and Its Determinate Factors Among Adults on First Line Antiretroviral Treatment at Defence Main Health Department - Level II & Level III Hospitals In Ethiopia

Introduction: Highly active antiretroviral therapy (HAART) played a critical role in the medical management of HIV infected individuals by restoring the immune function and minimizes HIV related outcomes. But treatment failure minimized these advantages and leads to an increment of morbidity and mortality with poor quality of life in all HIV patients. Objective: The aim of this study was to assess the virological treatment failure and its determinant factors of patients on first line HAART at five commandant Hospitals, Ethiopia. Methods: A Retrospective hospital based study design was used to determine magnitude of treatment/virology failure and its determinant factors, among HIV positive adults enrolled to HAART program at five commandant Hospitals from February 1 to May 30, 2018. Data abstracted from patient charts or electronic data base was cleaned, coded, entered and analyzed using EPI data version 3.1 and SPSS version 23 statistical software package. Descriptive statistics, proportion of treatment failure cases among those diagnosed to have treatment failure was calculated. Bi-variate and multiple logistic regressions were used to analysis association between the outcome and the independent variables were taken as significant at P&lt;0.05 (2 tail test) and 95% confidence intervals (CIs). Result: Among the 326 participants enrolled, 229(70.2%) were males. The mean ages were 36.84 years (SD+7.716) years and the median months on HAART from initiation were 81.50 months. A total of 75(23%) participants were found to have treatment failure among those 50(15.3%) immunological failure, 7(2.1%) virological failure and 16(4.9%) all Treatment failure (VF, IF&amp;CF in one). The mean CD4 T-cells at base line and at study time were 213.3 cells/ µl. Long duration on treatment (AOR= 4.231, 95% CI: 1.453-12.320) , IPT cycle (AOR = 3.060, 95% CI: 1.388-6.746), Type of drug AZT based therapy (AOR= 2.572, 95% CI: 1.357-4.875), experience of PEP (AOR=7.950, 95% CI: 1.945-66.915) and lost to follow up (AOR= 9.104, 95% CI: 2.973-27.873) were found to be significant predictors of treatment/virologic failure and showed positive odds ratio. Conclusion: This study demonstrates high treatment /virologic failure and the determinant factors of treatment/virologic failures among HAART first line adult are still changing. Therefore, evidence-based intervention and early detection of treatment failure must be made to further identify the potential causes and set standardized protective mechanisms of treatment/virologic failures.

Correlation between early dynamics in circulating tumour DNA and outcome from FOLFIRI treatment in metastatic colorectal cancer

Chemotherapy resistance remains a challenge in the clinical management of metastatic colorectal cancer (mCRC). Here, early changes in cell-free circulating tumour DNA (ctDNA) levels were explored as a marker of therapeutic efficacy. Twenty-four mCRC patients were enrolled and treated with FOLFIRI based first-line therapy. Blood samples collected pre-treatment, at day 7, 14, 21, 60 and at progression were analysed for cell-free DNA (cfDNA) and ctDNA levels using digital droplet PCR. A subset of samples were additionally analysed by targeted sequencing. Patients with high pre-treatment ctDNA or cfDNA levels (≥75th centile) had significantly shorter progression free survival (PFS) than patients with lower levels. Despite an overall decline in ctDNA levels from pre-treatment to first CT-scan, serial analysis identified seven patients with temporary increases in ctDNA consistent with growth of resistant cells. These patients had shorter PFS and shorter overall survival. Targeted sequencing analyses of cfDNA revealed dramatic changes in the clonal composition in response to treatment. Our study suggests that increasing ctDNA levels during the first cycles of first-line FOLFIRI treatment is a predictor of incipient progressive disease and poorer survival. Thus, we demonstrate the importance of monitoring ctDNA levels as early as one week after treatment onset to enable early detection of treatment failure.

Tracking endocrine resistance in estrogen-receptor positive breast cancer in ctDNA.

e14550 Background: Endocrine therapy is the standard of care treatment for patients with estrogen-receptor positive advanced breast cancer, owing to improved tolerability and comparable efficacy to that of cytotoxic chemotherapy. Half of such cancers will progress through first line therapy (primary endocrine resistance) and half will progress after an initial period of disease control (secondary or acquired endocrine resistance). A significant challenge is to test for and identify biomarkers which can guide the likely success of endocrine therapy as a single agent or in combination with small molecule inhibitors.This is particularly challenging where metastatic deposits reside at sites where biopsy is difficult. Potential biomarkers indicative of resistance to endocrine therapy have been identified and can be detected in circulating tumour DNA (ctDNA). CtDNA is shed from tumours and is detectable in a cancer patient’s bloodstream. Information on mutational profiles can guide an oncologist in the selection of targeted therapy in addition to hormonal therapy. Methods: We have analysed formalin-fixed paraffin-embedded(FFPE) tumour samples and longitudinal liquid biopsies from 19 patients who were treated with fulvestrant in combination with a novel inhibitor of the PIK3CA/AKT pathway with next-generation sequencing using a targeted 44-gene panel. Mutations identified using this technique were tracked during the course of treatment using droplet-digital PCR(ddPCR). Results: 57 samples were tested using a 44-gene panel; 19 FFPE tumour samples and matched ctDNA samples were obtained prior therapy and ctDNA samples at disease progression. Mutations detected in PIK3CA, AKT1, ESR1and TP53 genes were trackable in longitudinal ctDNA samples using ddPCR. The association between ctDNA dynamics and outcome will be presented. Conclusions: Multiple mutations that enable the early detection of treatment failure and resistance can be tracked in ctDNA. Investigating the clinical utility of ctDNA is paramount.

Abstract 3617: Prediction of irinotecan and flurouracil efficacy in metastatic colorectal cancer by early measurement of circulating tumor DNA

Abstract Background: Chemotherapy resistance in metastatic colorectal cancer (mCRC) is a major challenge, and development of biomarkers for determining therapy efficacy is vital to ensure optimal palliative treatment. Recently, quantification of changes in circulating tumor DNA (ctDNA) levels has attracted substantial attention as a predictive marker. Here, we provide evidence that ctDNA has the potential to be used as an early marker of therapeutic efficacy of irinotecan and fluorouracil (FOLFIRI). Experimental Procedures: Patients diagnosed with mCRC, and with indication for first-line combination chemotherapy, were prospectively enrolled in this phase II study. Blood was drawn at baseline, day 7, 14, 21, 40 and then monthly until progression. Response evaluation was done at eight-week intervals by CT scanning using RECIST criteria. Chemotherapy was administered at day one and two every two weeks. The levels of cell-free DNA (cfDNA) and ctDNA were determined using sensitive digital droplet PCR assays. ctDNA assays were designed either to mutations identified by targeted sequencing or on basis of known tumor mutations detected in primary or metastatic lesions using a panel of mutation-specific qPCR based assays (KRAS, NRAS, BRAF). Results: Twenty-four patients were enrolled. A KRAS, NRAS or BRAF mutation was observed in tumor tissue of 16 patients. In 12 of these the mutations were confirmed in baseline samples and used for assessing ctDNA. For the remaining 12 patients, a mutation for ctDNA quantification was identified by targeted tumor sequencing. Patients with high baseline ctDNA levels (75th centile) had significantly shorter progression-free survival (PFS) than patients with low baseline ctDNA levels. After first treatment cycle all patients experienced a decline in ctDNA levels demonstrating initial response to treatment; however, the reduction in ctDNA was not associated with prolonged PFS or overall survival (OS). Conversely, change in ctDNA levels from first to second cycle of treatment (three weeks after treatment start) predicted FOLFIRI efficacy. Patients with increasing ctDNA levels at this time point had a significantly shorter PFS and a shorter OS than patients with stable or decreasing ctDNA levels. Conclusion: In agreement with the literature, we show that baseline tumor DNA levels predicted PFS. The initial observed decline in ctDNA levels upon administration of FOLFIRI indicates that all tumors had cancer cells sensitive to treatment; however, after elimination of these, resistant clones expanded, leading to treatment resistance. Importantly, our study demonstrates that FOLFIRI efficacy can be evaluated as early as three weeks after treatment initiation by measurement of ctDNA levels. This enables early detection of treatment failure and allows for rapid adaptation of the treatment strategy. Citation Format: Iben Lyskjær, Camilla J. Kronborg, Mads H. Rasmussen, Boe S. Sørensen, Mona Rosenkilde, Michael Knudsen, Søren R. Krag, Karen-Lise G. Spindler, Claus L. Andersen. Prediction of irinotecan and flurouracil efficacy in metastatic colorectal cancer by early measurement of circulating tumor DNA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3617.