New strategies in the diagnosis and treatment of immune-checkpoint inhibitor-mediated colitis

Immune-checkpoint inhibitor-mediated colitis(IMC)is an increasingly recognized adverse event in cancer immunotherapy,particularly associated with immune checkpoint inhibitors(ICIs)such as anti-cytotoxic T-lymphocyte antigen-4 and anti-programmed cell death protein-1 antibodies.As this revolutionary immunotherapy gains prominence in cancer treatment,understanding,diagnosing,and effectively managing IMC becomes paramount.IMC represents a unique challenge due to its immune-mediated nature and potential for severe complications.However,a precise picture of IMC pathophysiology is currently unavailable.Therefore,we aimed to summarize the existing data while acknowledging the need for further research.This comprehensive review explores the mechanisms underlying ICIs,gastrointestinal adverse effects,and,in particular,IMC’s incidence,prevalence,and features.Our review also emphasizes the importance of recognizing IMC’s distinct clinical and histopathological features to differentiate it from other forms of colitis.Furthermore,this paper highlights the urgentneed for evolving diagnostic methods,therapeutic strategies,and a multidisciplinary approach to effectively manage IMC.

Research Progress of Drug Therapy for Diabetes

Diabetes is mainly a series of symptoms of glucose metabolism disorder caused by relative or absolute insufficiencies of insulin.Most patients are accompanied by protein,fat,water and electrolyte disorders,including diabetes type 1 and diabetes type 2,of which diabetes type 2 accounts for more than 90%.The incidence rate of diabetes is high,the course of disease is long,and it is difficult to cure.Most patients need long-term medication.This study analyzed the clinical manifestations and predisposing factors of diabetes,and explored the progress of drug treatment of diabetes,which is summarized as follows.

Observation on the Clinical Effect of Applying Venetoclax Combined with Demethylation Drug Therapy in Patients with Acute Myeloid Leukemia

Objective: To investigate the therapeutic effect of applying venetoclax combined with demethylating drugs in treating patients with acute myeloid leukemia (AML). Methods: Eighty cases of AML patients treated with venetoclax combined with demethylating drugs in our hospital were selected from March 2021 to March 2024, including 40 cases of primary treatment patients and 40 cases of relapsed and refractory patients. The efficacy and safety of the combined drug therapy was analyzed. Results: The primary treatment group was presented with a complete remission (CR) rate of 40.5%, partial remission (PR) rate of 47.50%, no response (NR) rate of 12.50%, and a remission rate of 87.50%. The relapsed- refractory group was presented with a CR rate of 37.50%, PR rate of 42.50%, NR rate of 17.50%, and a remission rate of 87.50%. There was no statistical significance between the groups (P > 0.05). The hematological adverse reactions of the combined treatment for AML were leukopenia and the non-hematological adverse reactions were mainly infections, with an incidence rate of 87.50%. Conclusion: The efficacy of venetoclax combined with demethylating drugs in AML was remarkable and the treatment regimen can be adjusted according to the treatment-resistant response.

Intestinal complications in Brazilian patients with ulcerative colitis treated with conventional therapy between 2011 and 2020

BACKGROUND This was an observational, descriptive, and retrospective study from 2011 to 2020 from the Department of Informatics of the Brazilian Healthcare System database.AIM To describe the intestinal complications(IC) of patients with ulcerative colitis(UC) who started conventional therapies in Brazil’s public Healthcare system.METHODS Patients ≥ 18 years of age who had at least one claim related to UC 10th revision of the International Statistical Classification of Diseases and Related Health Problems(ICD-10) code and at least 2 claims for conventional therapies were included. IC was defined as at least one claim of: UC-related hospitalization, procedures code for rectum or intestinal surgeries, and/or associated disease defined by ICD-10 codes(malignant neoplasia of colon, stenosis, hemorrhage, ulcer and other rectum or anus disease, megacolon, functional diarrhea volvulus, intussusception and erythema nodosum). Descriptive statistics, annual incidence, and incidence rate(IR) [per 100 patient-years(PY)] over the available follow-up period were calculated.RESULTS In total, 41229 UC patients were included(median age, 48 years;65% women) and the median(interquartile range) follow-up period was 3.3(1.8-5.3) years. Conventional therapy used during follow-up period included: mesalazine(87%), sulfasalazine(15%), azathioprine(16%) or methotrexate(1%) with a median duration of 1.9(0.8-4.0) years. Overall IR of IC was 3.2 cases per 100 PY. Among the IC claims, 54% were related to associated diseases, 20% to procedures and 26% to hospitalizations. The overall annual incidence of IC was 2.9%, 2.6% and 2.5% in the first, second and third year after the first claim for therapy(index date), respectively. Over the first 3 years, the annual IR of UC-related hospitalizations ranged from 0.8% to 1.1%;associated diseases from 0.9% to 1.2%-in which anus or rectum disease, and malignant neoplasia of colon were the most frequently reported;and procedure events from 0.6% to 0.7%, being intestinal resection and polyp removal the most frequent ones.CONCLUSION Study shows that UC patients under conventional therapy seem to present progression of disease developing some IC, which may have a negative impact on patients and the burden on the health system.

Ionizable drug delivery systems for efficient and selective gene therapy

Gene therapy has shown great potential to treat various diseases by repairing the abnormal gene function.However,a great challenge in bringing the nucleic acid formulations to the market is the safe and effective delivery to the specific tissues and cells.To be excited,the development of ionizable drug delivery systems(IDDSs)has promoted a great breakthrough as evidenced by the approval of the BNT162b2 vaccine for prevention of coronavirus disease 2019(COVID-19)in 2021.Compared with conventional cationic gene vectors,IDDSs can decrease the toxicity of carriers to cell membranes,and increase cellular uptake and endosomal escape of nucleic acids by their unique pH-responsive structures.Despite the progress,there remain necessary requirements for designing more efficient IDDSs for precise gene therapy.Herein,we systematically classify the IDDSs and summarize the characteristics and advantages of IDDSs in order to explore the underlying design mechanisms.The delivery mechanisms and therapeutic applications of IDDSs are comprehensively reviewed for the delivery of plasmid DNA(pDNA)and four kinds of RNA.In particular,organ selecting considerations and high-throughput screening are highlighted to explore efficiently multifunctional ionizable nanomaterials with superior gene delivery capacity.We anticipate providing references for researchers to rationally design more efficient and accurate targeted gene delivery systems in the future,and indicate ideas for developing next generation gene vectors.

Current medical therapy for ulcerative colitis

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Pseudomembranous colitis associated with a triple therapy for Helicobacter pylori eradication

Helicobacter pylori(H.pylori)is one of the most common chronic bacterial infections in humans,affecting half of world’s population.Therapy for H.pylori infection has proven to be both effective and safe.The oneweek triple therapy including proton pump inhibitor,clarithromycin,and amoxicillin or metronidazole is still recommended as a first-line treatment to eradicate H.pylori infection in countries with low clarithromycin resistance.Generally,this therapy is well-tolerated,with only a few and usually minor side effects.However,rare but severe adverse effects such as pseudomembranous colitis have been reported,Clostridium difficile(C.difficile)infection being the main causative factor in all cases.We report the cases of two women who developed pseudomembranous colitis after a 1-wk triple therapy consisting of pantoprazole 20 mg bid,clarithromycin 500 mg bid,and amoxicillin 1 g bid to eradicate H.pylori infection.A limited colonoscopy showed typical appearance of pseudomembranous colitis,and the stool test for C.difficile toxins was positive.Rapid resolution of symptoms and negative C.difficile toxins were obtained in both patients with oral vancomycin.No relapse occurred during a four and eleven-month,respectively,follow up.These cases suggest that physicians should have a high index of suspicion for pseudomembranous colitis when evaluate patients with diarrhea following H.pylori eradication therapy.

Promising biological therapies for ulcerative colitis: A review of the literature

Ulcerative colitis(UC) is a chronic lifelong condition characterized by alternating flare-ups and remission. There is no single known unifying cause, and the pathogenesis is multifactorial, with genetics, environmental factors, microbiota, and the immune system all playing roles. Current treatment modalities for UC include 5-aminosalicylates, corticosteroids, immunosuppressants(including purine antimetabolites, cyclosporine, and tacrolimus), and surgery. Therapeutic goals for UC are evolving. Medical treatment aims to induce remission and prevent relapse of disease activity. Infliximab, an anti-tumor necrosis factor(TNF)-α monoclonal antibody, is the first biological agent for the treatment of UC. Over the last decade, infliximab and adalimumab(anti-TNF-α agents) have been used for moderate to severe UC, and have been shown to be effective in inducing and maintaining remission. Recent studies have indicated that golimumab(another anti-TNF-α agent), tofacitinib(a Janus kinase inhibitor), and vedolizumab and etrolizumab(integrin antagonists), achieved good clinical remission and response rates in UC. Recently, golimumab and vedolizumab have been approved for UC by the United States Food and Drug Administration. Vedolizumab may be used as a first-line alternative to anti-TNF-α therapy in patients with an inadequate response to corticosteroids and/or immunosuppressants. Here, we provide updated information on various biological agents in the treatment of UC.

Triggers of histologically suspected drug-induced colitis

BACKGROUND Drug toxicity is a common and even serious problem in the gastrointestinal tract that is thought to be caused by a broad spectrum of agents.Although withdrawal of the causative agent would cure the disease knowledge is scarce and mostly derives from case reports and series.AIM To investigate potential triggers of drug-induced colitis(DiC).METHODS We conducted a retrospective,observational case control study.Patients were assigned to DiC or one of two age-and gender-matched control groups(noninflammatory controls and inflammatory colitis of another cause)based on histopathological findings.Histopathology was reassessed in a subset of patients(28 DiC with atherosclerosis,DiC without atherosclerosis and ischaemic colitis each)for validation purposes.Medical history was collected from the electronic database and patient records.Statistical analysis included chi-squared test,t-test,logistic and multivariate regression models.RESULTS Drug-induced colitis was detected in 211 endoscopically sampled biopsy specimens of the colon mucosa(7%of all screened colonoscopic biopsy samples);a total of 633 patients were included equally matched throughout the three groups(291 males,mean age:62.1±16.1 years).In the univariate analysis,DiC was associated with diuretics,dihydropyridines,glycosides,ASS,platelet aggregation inhibitors,nonsteroidal anti-inflammatory drugs(NSAIDs),statins and fibrates,and with atherosclerosis,particularly coronary heart disease,and hyperlipoproteinaemia.Echocardiographic parameters did not show substantial differences.In the multivariate analysis only fibrates[odds ratio(OR)=9.1],NSAIDs(OR=6.7)and atherosclerosis(OR=2.1)proved to be associated with DiC.Both DiC reassessment groups presented milder inflammation than ischaemic colitis.The DiC patients with atherosclerosis exhibited histological features from both DiC without atherosclerosis and ischaemic colitis.CONCLUSION Several drugs indicated for the treatment of cardiovascular and related diseases are associated with DiC.Atherosclerosis and microcirculatory disturbances seem to play an important pathogenetic role.

Older adults with acute severe ulcerative colitis have similar steroid non-response and colectomy rates as younger adults

BACKGROUND There is paucity of data on outcomes of acute severe ulcerative colitis(ASUC)in older adults(≥60 years of age).AIM To assess steroid non-response rates during the index admission for ASUC in older adults.Secondary outcomes were response to medical rescue therapy and colectomy rates;at index admission,3 and 12 mo.METHODS This retrospective multicentre cohort study included ASUC admissions who received intravenous steroids between January 2013 and July 2020 at two tertiary hospitals.Electronic medical records were reviewed to collect clinical,biochemical,and endoscopic data.A modified Poisson regression model was used for analysis.RESULTS Of 226 ASUC episodes,45(19.9%)occurred in patients≥60 years of age.Steroid non-response rates were comparable in older adults and patients<60 years of age[19(42.2%)vs 85(47%),P=0.618],crude risk ratio(RR)=0.89[95%confidence interval(CI):0.61-1.30],adjusted RR=0.99(0.44-2.21).Rates of response to medical rescue therapy in older adults was comparable to the younger cohort[76.5%vs 85.7%,P=0.46,crude RR=0.89(0.67-1.17)].Index admission colectomy[13.3%vs 10.5%,P=0.598,crude RR=1.27(0.53-2.99),adjusted RR=1.43(0.34-6.06)],colectomy at 3 mo[20%vs 16.6%,P=0.66,crude RR=1.18(0.61-2.3),adjusted RR=1.31(0.32-0.53)]and colectomy at 12 mo[20%vs 23.2%,P=0.682,crude RR=0.85(0.45-1.57),adjusted RR=1.21(0.29-4.97)],were similar between the two groups.CONCLUSION In older adults with ASUC,the steroid non-response rate,response to medical rescue therapy,and colectomy rate at index admission,3 and 12 mo is similar to patients less than 60 years of age.

Dual pH and microbial-sensitive galactosylated polymeric nanocargoes for multi-level targeting to combat ulcerative colitis

Ulcerative colitis(UC)is a type of inflammatory bowel disease characterized by inflammation,ulcers and irritation of the mucosal lining.Oral drug delivery in UC encounters challenges because of multifaceted barriers.Dexamethasone-loaded galactosylated-PLGA/Eudragit S100/pullulan nanocargoes(Dexa-GP/ES/Pu NCs)have been developed with a dual stimuli-sensitive coating responsive to both colonic pH and microbiota,and an underneath galactosylated-PLGA core(GP).The galactose ligand of the GP preferentially binds to the macrophage galactose type-lectin-C(MGL-2)surface receptor.Therefore,both stimuli and ligand-mediated targeting facilitate nanocargoes to deliver Dexa specifically to the colon with enhanced macrophage uptake.Modified emulsion method coupled with a solvent evaporation coating technique was employed to prepare Dexa-GP/ES/Pu NCs.The nanocargoes were tested using in vitro,ex vivo techniques and dextran sodium sulfate(DSS)induced UC model.Prepared nanocargoes had desired physicochemical properties,drug release,cell uptake and cellular viability.Investigations using a DSS-colitis model showed high localization and mitigation of colitis with downregulation of NF-ĸB and COX-2,and restoration of clinical,histopathological,biochemical indices,antioxidant balance,microbial alterations,FTIR spectra,and epithelial junctions’integrity.Thus,Dexa-GP/ES/Pu NCs found to be biocompatible nanocargoes capable of delivering drugs to the inflamed colon with unique targeting properties for prolonged duration.

HIV-1 Subtype Diversity and Factors Affecting Drug Resistance among Patients with Virologic Failure in Antiretroviral Therapy in Hainan Province,China,2014–2020

Objective This study aimed to determine the HIV-1 subtype distribution and HIV drug resistance(HIVDR)in patients with ART failure from 2014 to 2020 in Hainan,China.Methods A 7-year cross-sectional study was conducted among HIV/AIDS patients with ART failure in Hainan.We used online subtyping tools and the maximum likelihood phylogenetic tree to confirm the HIV subtypes with pol sequences.Drug resistance mutations(DRMs)were analyzed using the Stanford University HIV Drug Resistance Database.Results A total of 307 HIV-infected patients with ART failure were included,and 241 available pol sequences were obtained.Among 241 patients,CRF01_AE accounted for 68.88%,followed by CRF07_BC(17.00%)and eight other subtypes(14.12%).The overall prevalence of HIVDR was 61.41%,and the HIVDR against non-nucleoside reverse transcriptase inhibitors(NNRTIs),nucleotide reverse transcriptase inhibitors(NRTIs),and protease inhibitors(PIs)were 59.75%,45.64%,and 2.49%,respectively.Unemployed patients,hypoimmunity or opportunistic infections in individuals,and samples from 2017 to 2020 increased the odd ratios of HIVDR.Also,HIVDR was less likely to affect female patients.The common DRMs to NNRTIs were K103N(21.99%)and Y181C(20.33%),and M184V(28.21%)and K65R(19.09%)were the main DRMs against NRTIs.Conclusion The present study highlights the HIV-1 subtype diversity in Hainan and the importance of HIVDR surveillance over a long period.

Keratinocyte growth factor gene therapy ameliorates ulcerative colitis in rats

AIM:To investigate the effect of keratinocyte growth factor(KGF) gene therapy in acetic acid-induced ulcerative colitis in rat model.METHODS:The colitis of Sprague-Dawley rats was induced by intrarectal infusion of 1 mL 5%(v/v) acetic acid.Twenty-four hours after exposed to acetic acid,rats were divided into three experimental groups:control group,attenuated Salmonella typhimurium Ty21a strain(SP) group and SP strain carrying human KGF gene(SPK) group,and they were separately administered orally with 10% NaHCO3,SP or SPK.Animals were sacrificed and colonic tissues were harvested respectively on day 3,5,7 and 10 after administration.Weights of rats,colonic weight/length ratio and stool score were evaluated.Histological changes of colonic tissues were examined by hematoxylin and eosin(HE) staining method.The expression of KGF,KGF receptor(KGFR) and TNF-α were measured either by enzyme-linked immunosorbent assay or Western blotting.Immunohistochemistry was used to detect the cellular localization of KGFR and Ki67.In addition,superoxide dismutase(SOD) activity and malondialdehyde(MDA) contents in the homogenate were measured.RESULTS:Body weight and colonic weight/length ratio were declined in SPK group compared with SP and control groups(body weight:272.78 ± 17.92 g vs 243.72 ± 14.02 g and 240.68 ± 12.63 g,P < 0.01;colonic weight/length ratio:115.76 ± 7.47 vs 150.32 ± 5.99 and 153.67 ± 5.50 mg/cm,P < 0.01).Moreover,pathological changes of damaged colon were improved in SPK group as well.After administration of SPK strain,KGF expression increased markedly from the 3rd d,and remained at a high level till the 10th d.Furthermore,KGFR expression and Ki67 expression elevated,whereas TNF-α expression was inhibited in SPK group.In the group administered with SPK,SOD activity increased significantly(d 5:26.18 ± 5.84 vs 18.12 ± 3.30 and 18.79 ± 4.74 U/mg,P < 0.01;d 7:35.48 ± 3.35 vs 22.57 ± 3.44 and 21.69 ± 3.94 U/mg,P < 0.01;d 10:46.10 ± 6.23 vs 25.35 ± 4.76 and 27.82 ± 6.42 U/mg,P < 0.01) and MDA contents decreased accordingly(d 7:7.40 ± 0.88 vs 9.81 ± 1.21 and 10.45 ± 1.40 nmol/mg,P < 0.01;d 10:4.36 ± 0.62 vs 8.41 ± 0.92 and 8.71 ± 1.27 nmol/mg,P < 0.01),compared with SP and control groups.CONCLUSION:KGF gene therapy mediated by attenuated Salmonella ameliorates ulcerative colitis induced by acetic acids,and it may be a safe and effective treatment for ulcerative colitis.

Severe chest pain in a pediatric ulcerative colitis patient after 5-aminosalicylic acid therapy

Severe reactions to mesalamine products are rarely seen in pediatric patients. We report a case of a 12-year-old boy who had a severe cardiac reaction to a mesalamine product Asacol. Past medical history is significant for ulcerative colitis (UC) diagnosed at 9 years of age. Colo- noscopy one week prior to admission revealed pancoli- tis. He was treated with Asacol 800 mg three times per day and prednisone 20 mg/d. He was subsequently ad- mitted to the hospital for an exacerbation of his UC and started on intravenous solumedrol. He had improvement of his abdominal pain and diarrhea. The patient com- plained of new onset of chest pain upon initiating Asacol therapy. Electrocardiogram (ECG) revealed non-specific ST-T wave changes with T-wave inversion in the lateral leads. Echocardiogram (ECHO) revealed low-normal to mildly depressed left ventricular systolic function. The left main coronary artery and left anterior descending artery were mildly prominent measuring 5 mm and 4.7 mm, respectively. His chest pain completely resolved within 24-36 h of discontinuing Asacol. A repeat echo- cardiogram performed two days later revealed normal left ventricular function with normal coronary arteries (< 3.5 mm). Onset of chest pain after Asacol and im- mediate improvement of chest pain, as well as improve- ment of echocardiogram and ECG findings after discon- tinuing Asacol suggests that our patient suffered from a rare drug-hypersensitivity reaction to Asacol.

Early aggressive therapy for severe extensive ulcerative colitis

The current ulcerative colitis (UC) treatment algorithm involves a step-up therapeutic strategy, mainly aiming at inducing and maintaining its clinical remission. Although this therapeutic strategy may seem to be cost-efficient and reduce the risk of side effects, recent trials and case reports have shown that top-down therapy using in· iximab induces a rapid clinical response, enhances patient quality of life, promotes mucosal healing, reduces surgeries and indirect cost of treatment for patients with severe UC. Moreover, since long-term treatment with in· iximab is safe and well tolerated, early aggressive top-down therapeutic strategy may be a more effective approach, at least in a subgroup of severe extensive UC patients.

Dysregulation of innate immunity in ulcerative colitis patients who fail anti-tumor necrosis factor therapy

AIM To study the innate immune function in ulcerative colitis(UC) patients who fail to respond to anti-tumor necrosis factor(TNF) therapy.METHODS Effects of anti-TNF therapy, inflammation and medications on innate immune function were assessed by measuring peripheral blood mononuclear cell(PBMC) cytokine expression from 18 inflammatory bowel disease patients pre- and 3 mo post-anti-TNF therapy. Toll-like receptor(TLR) expression and cytokine production post TLR stimulation was assessed in UC "responders"(n = 12) and "non-responders"(n = 12) and compared to healthy controls(n = 12). Erythrocyte sedimentation rate(ESR) and C-reactive protein(CRP) levels were measured in blood to assess disease severity/activity and inflammation. Pro-inflammatory(TNF, IL-1β, IL-6), immuno-regulatory(IL-10), Th1(IL-12, IFNγ) and Th2(IL-9, IL-13, IL-17A) cytokine expression was measured with enzyme-linked immunosorbent assay while TLR cellular composition and intracellular signalling was assessed with FACS.RESULTS Prior to anti-TNF therapy, responders and nonresponders had similar level of disease severity and activity. PBMC's ability to respond to TLR stimulation was not affected by TNF therapy, patient's severity of the disease and inflammation or their medication use. At baseline, non-responders had elevated innate but not adaptive immune responses compared to responders(P < 0.05). Following TLR stimulation, nonresponders had consistently reduced innate cytokine responses to all TLRs compared to healthy controls(P < 0.01) and diminished TNF(P < 0.001) and IL-1β(P < 0.01) production compared to responders. This innate immune dysfunction was associated with reduced number of circulating plasmacytoid dendritic cells(p DCs)(P < 0.01) but increased number of CD4+ regulatory T cells(Tregs)(P = 0.03) as well as intracellular accumulation of IRAK4 in non-responders following TLR-2,-4 and-7 activation(P < 0.001). CONCLUSION Reduced innate immunity in non-responders may explain reduced efficacy to anti-TNF therapy. These serological markers may prove useful in predicting the outcome of costly anti-TNF therapy.

Biological therapy for ulcerative colitis:An update

Of the diverse biological agents used for patients with ulcerative colitis, the anti-tumor necrosis factor-αagents infliximab and adalimumab have been used in large-scale clinical trials and are currently widely used in the treatment of inflammatory bowel disease patients. Recent studies have indicated that golimumab,oral tofacitinib and vedolizumab reportedly achieved good clinical response and remission rates in ulcerative colitis patients. Thus, we believe that the detailed investigation of various studies on clinical trials may provide important information for the selection of appropriate biological agents, and therefore, we have extensively reviewed such trials in the present study.

Frequency and prognostic role of mucosal healing in patients with Crohn's disease and ulcerative colitis after one-year of biological therapy

AIM:To assess the endoscopic activity before and after a one-year period of biological therapy and to evaluate the frequency of relapses and need for retreatment after stopping the biologicals in patients with Crohn’s disease(CD)and ulcerative colitis(UC).METHODS:The data from 41 patients with CD and 22 patients with UC were assessed.Twenty-four CD patients received infliximab,and 17 received adalimumab.The endoscopic severity of CD was quantified with the simplified endoscopic activity score for Crohn’s disease in CD and with the Mayo endoscopic subscore in UC.RESULTS:Mucosal healing was achieved in 23 CD and7 UC patients.Biological therapy had to be restarted in78%of patients achieving complete mucosal healing with CD and in 100%of patients with UC.Neither clinical remission nor mucosal healing was associated with the time to restarting the biological therapy in either CD or UC.CONCLUSION:Mucosal healing did not predict sustained clinical remission in patients in whom the biological therapies had been stopped.

MATHEMATICAL MODELING AND BIFURCATION ANALYSIS FOR A BIOLOGICAL MECHANISM OF CANCER DRUG RESISTANCE

Drug resistance is one of the most intractable issues in targeted therapy for cancer diseases.It has also been demonstrated to be related to cancer heterogeneity,which promotes the emergence of treatment-refractory cancer cell populations.Focusing on how cancer cells develop resistance during the encounter with targeted drugs and the immune system,we propose a mathematical model for studying the dynamics of drug resistance in a conjoint heterogeneous tumor-immune setting.We analyze the local geometric properties of the equilibria of the model.Numerical simulations show that the selectively targeted removal of sensitive cancer cells may cause the initially heterogeneous population to become a more resistant population.Moreover,the decline of immune recruitment is a stronger determinant of cancer escape from immune surveillance or targeted therapy than the decay in immune predation strength.Sensitivity analysis of model parameters provides insight into the roles of the immune system combined with targeted therapy in determining treatment outcomes.

Discontinuation of therapy in inflammatory bowel disease: Current views

The timely introduction and adjustment of the appropriate drug in accordance with previously well-defined treatment goals is the foundation of the approach in the treatment of inflammatory bowel disease(IBD).The therapeutic approach is still evolving in terms of the mechanism of action but also in terms of the possibility of maintaining remission.In patients with achieved long-term remission,the question of de-escalation or discontinuation of therapy arises,considering the possible side effects and economic burden of long-term therapy.For each of the drugs used in IBD(5-aminosalycaltes,immunomodulators,biological drugs,small molecules)there is a risk of relapse.Furthermore,studies show that more than 50%of patients who discontinue therapy will relapse.Based on the findings of large studies and meta-analysis,relapse of disease can be expected in about half of the patients after therapy withdrawal,in case of monotherapy with aminosalicylates,immunomodulators or biological therapy.However,longer relapse-free periods are recorded with withdrawal of medication in patients who had previously been on combination therapies immunomodulators and anti-tumor necrosis factor.It needs to be stressed that randomised clinical trials regarding withdrawal from medications are still lacking.Before making a decision on discontinuation of therapy,it is important to distinguish potential candidates and predictive factors for the possibility of disease relapse.Fecal calprotectin level has currently been identified as the strongest predictive factor for relapse.Several other predictive factors have also been identified,such as:High Crohn's disease activity index or Harvey Bradshaw index,younger age(<40 years),longer disease duration(>40 years),smoking,young age of disease onset,steroid use 6-12 months before cessation.An important factor in the decision to withdraw medication is the success of re-treatment with the same or other drugs.The decision to discontinue therapy must be based on individual approach,taking into account the severity,extension,and duration of the disease,the possibility of side adverse effects,the risk of relapse,and patient’s preferences.