HIV-1耐药性基因型检测法在临床治疗随访中的应用

目的 探索HIV-1耐药性基因型检测法在高效抗逆转录病毒疗法（HAART）治疗组中监测HIV-1耐药性病毒株的临床应用。方法 从接受HAART的HIV-1感染者血浆中抽提病毒RNA,采用套式RT-PCR方法扩增HIV-1的PR和RT基因片段,并对扩增片段进行序列测定和分析。结果HIV-1耐药性基因型检测法能够从血浆病毒载量在 1000拷贝/ml以上的样本中得到扩增产物。在 16例接受 HAART的 HIV-1感染者中,发现 1例感染者 DP31的 PR和 RT基因出现了突变,这些突变为L63P、T215F、K219Q和M184V。所有突变均与公开报道的结果一致,并被证明与HIV-1的耐药性有关。另外,DP31在接受HAART前已出现T215F、K219Q的耐药性突变,究其原因,还有待进一步研究。结论HIV-1耐药性基因型检测法能有效地监测接受HAART的HIV-1感染者血浆中耐药性病毒株的存在。该方法提供的结果准确、可靠,并且为临床医生评价HAART效果,合理选择和及时优化药物组合方案提供了可靠的依据。     

Approach to treatment of patients with virologic failure to multiple regimens

Second-line and rescue antiretrovirals regimens have a poor success record only 30-45% achieves viral suppression. This rate will be improved if salvage therapy is individualized with a better understanding what causes previous failures, establishing reasonable goals of therapy for the patient and speaking with him about the pros and the cons of the new regimens.Before deciding the change we must have available the first and the present HIV RNA levels, absolute CD4 T cell count and changes in these counts, prior antiretroviral therapies, resistance test, assessment of adherence to medications, and preparation of the patient for the implications of the new regimens. Carrying out drug salvage levels and the inhibitory quotient probably can be important.In patients on therapy with detectable but low (< 5,000 copies/ml) stable HIV RNA levels the risk of clinical or immunologic failure is low. Recent reports provide support for a conservative strategy, particularly for those patients with limited therapeutic options.In-patients who are failing their second regimen it is important to use at least two new susceptible drugs, with a high potency and using combinations that assure high drug levels. In this population treatment interruption as a strategy for managing drug resistance is in study.New therapies such as DAPD, tenofovir, TMC 120, lopinavir, tipranavir and T-20 offer significant promise for the treatment of drug-experienced patients.     

Phenotypic or genotypic resistance testing for choosing antiretroviral therapy after treatment failure: a randomized trial

OBJECTIVE: To assess the respective value of phenotype versus genotype versus standard of care for choosing antiretroviral therapy in patients failing protease inhibitor-containing regimens. METHODS: Patients with plasma HIV-1 RNA exceeding 1000 copies/ml were randomly allocated to phenotyping, genotyping, or standard of care. RESULTS: Five-hundred and forty-one patients were randomized, 190 to phenotyping, 192 to genotyping and 159 to standard of care. The baseline median CD4 cell count (280 x 106 cells/l), the plasma HIV-1 RNA level (4.3 log10 copies/ml), and the number of drugs previously received (n = 6) were similar in the three arms. More patients in the standard-of-care arm received at least three new drugs (55% versus 20% in the other arms; P < 0.001) and a regimen containing drugs from the three different classes. Plasma HIV-1 RNA was < 200 copies/ml at week 12 in 35% of patients in the phenotyping arm, 44% in the genotyping arm and 36% in the standard-of-care arm (phenotyping versus standard of care, P = 0.918; genotyping versus standard of care, P = 0.120). In a secondary analysis of 179 patients experiencing a first protease inhibitor failure, the percentage of patients achieving HIV-1 RNA < 200 copies/ml was significantly higher in the genotyping arm (65%) than in the phenotyping (45%) and the standard-of-care arms (45%) (genotyping versus standard of care, P = 0.022). CONCLUSIONS: Overall, resistance assays did not demonstrate benefit over standard of care. In patients with the most limited protease inhibitor experience, a significant benefit was observed in the genotyping arm.     

Use of genotypic resistance testing to guide hiv therapy: clinical impact and cost-effectiveness

BACKGROUND: Genotypic sequencing for drug-resistant strains of HIV can guide the choice of antiretroviral therapy. OBJECTIVE: To assess the cost-effectiveness of genotypic resistance testing for patients acquiring drug resistance through failed treatment (secondary resistance) and those infected with resistant virus (primary resistance). DESIGN: Cost-effectiveness analysis with an HIV simulation model incorporating CD4 cell count and HIV RNA level as predictors of disease progression. DATA SOURCES: Published randomized trials and data from the Multicenter AIDS Cohort Study, the national AIDS Cost and Services Utilization Survey, the Red Book, and an institutional cost-accounting system. TARGET POPULATION: HIV-infected patients in the United States with baseline CD4 counts of 0.250 x 10(9) cells/L. TIME HORIZON: Lifetime. PERSPECTIVE: Societal. INTERVENTIONS: Genotypic resistance testing and clinical judgment, compared with clinical judgment alone, in two contexts: after initial treatment failure (secondary resistance testing) and before initiation of antiretroviral therapy (primary resistance testing). OUTCOME MEASURES: Life expectancy, quality-adjusted life expectancy, and cost-effectiveness in dollars per quality-adjusted life-year (QALY) gained. RESULTS OF BASE-CASE ANALYSIS: Secondary resistance testing increased life expectancy by 3 months, at a cost of $17 900 per QALY gained. The cost-effectiveness of primary resistance testing was $22 300 per QALY gained with a 20% prevalence of primary resistance but increased to $69 000 per QALY gained with 4% prevalence. RESULTS OF SENSITIVITY ANALYSIS: The cost-effectiveness ratio for secondary resistance testing remained under $25 000 per QALY gained, even when effectiveness and cost of testing and antiretroviral therapy, quality-of-life weights, and discount rate were varied. CONCLUSIONS: Genotypic antiretroviral resistance testing following antiretroviral failure is cost-effective. Primary resistance testing also seems to be reasonably cost-effective and will become more so as the prevalence of primary resistance increases.     

快速和早期病毒学应答对慢性丙型肝炎患者持续病毒学应答的预测价值

目的 探讨快速病毒学应答(RVR)和早期病毒学应答(EVR)对慢性丙型肝炎患者持续病毒学应答(SVR)的预测价值.方法 应用酶免疫方法检测105例慢性丙型肝炎患者基因型.患者给予聚乙二醇干扰素α-2a联合利巴韦林治疗.在治疗第4、12、24周和随访24周时检测患者的HCVRNA,观察不同时期的病毒学应答率以及对SVR的影响.结果 105例患者中,HCV基因1型44例,占41.9%;2型46例,占43.8%;3型15例,占14.3%.基因1型患者的RVR为51.2%,明显低于基因2或3型患者的73.8%(χ2=5.460,P=0.019);基因1型患者的EVR为73.2%,明显低于基因2或3型患者的96.7%(χ2=12.220,P=0.000);基因1型患者的SVR为43.9%,明显低于基因2或3型患者的75.4%(χ2=10.413,P=0.001).获得RVR的患者SVR为80.3%,明显高于未获得RVR的30.6%(χ2=24.662,P=0.000).RVR的阳性预测值均高于EVR,RVR的阴性预测值均低于EVR,但两者相比差异无统计学意义(P＞0.05).结论 基因1型患者的RVR、EVR和SVR均明显低于基因2或3型患者,RVR、EVR和SVR与基因型相关;RVR对慢性丙型肝炎患者SVR预测价值与EVR类似.     

Effect of zidovudine resistance mutations on virologic response to treatment with zidovudine-lamivudine-ritonavir: genotypic analysis of human immunodeficiency virus type 1 isolates from AIDS clinical trials group protocol 315.ACTG Protocol 315 Team

The effect of baseline drug resistance mutations on response to zidovudine, lamivudine, and ritonavir was evaluated in zidovudine-experienced persons infected with human immunodeficiency virus type 1 (HIV-1). Presence of the K70R mutation was associated with significantly higher plasma HIV-1 RNA levels at baseline. However, presence of resistance mutations did not affect the increase in plasma HIV-1 RNA during a 5-week drug washout, nor was there any effect on first-phase virus decay rates after initiation of therapy or on the probability of having plasma HIV-1 RNA levels <100 copies/mL at week 48. Polymorphisms at protease codons 10, 36, and 71 were associated with significantly faster second-phase decay rates. Suppression of plasma HIV-1 RNA despite presence of zidovudine resistance mutations implies that the presence of these mutations does not preclude a durable response to treatment with a potent 3-drug regimen.     

The long-term benefits of genotypic resistance testing in patients with extensive prior antiretroviral therapy: a model-based approach

OBJECTIVES: Resistance testing in HIV disease may provide long-term benefits that are not evident from short-term data. Our objectives were to estimate the long-term effectiveness, cost and cost-effectiveness of genotype testing in patients with extensive antiretroviral exposure. METHODS: We used an HIV simulation model to estimate the long-term effectiveness and cost-effectiveness of genotype testing. Clinical data incorporated into the model were from NARVAL, a randomized trial of resistance testing in patients with extensive antiretroviral exposure, and other randomized trials. Each simulated patient was eligible for up to three sequential regimens of antiretroviral therapy (i.e. two additional regimens beyond the trial-based regimen) using drugs not available at the time of the study, such as lopinavir/ritonavir, darunavir/ritonavir and enfuvirtide. RESULTS: In the long term, projected undiscounted life expectancy increased from 132.2 months with clinical judgement alone to 147.9 months with genotype testing. Median survival was estimated at 11.9 years in the resistance testing arm vs 10.4 years in the clinical judgement alone arm. Because of increased survival, the projected lifetime discounted cost of genotype testing was greater than for clinical judgement alone (euro313,900 vs euro263,100; US$399,000 vs US$334,400). Genotype testing cost euro69,600 (US$88,500) per quality-adjusted life year gained compared with clinical judgement alone. CONCLUSIONS: In patients with extensive prior antiretroviral exposure, genotype testing is likely to increase life expectancy in the long term as a result of the increased likelihood of receiving two active new drugs. Genotype testing is associated with cost-effectiveness comparable to that of strategies accepted in patients with advanced HIV disease, such as enfuvirtide use.     

Serum alpha-fetoprotein predicts virologic response to hepatitis C treatment in HIV coinfected patients

We explored the link between serum alpha-fetoprotein levels and virologic response in 383 HIV-hepatitis C virus coinfected patients. A low alpha-fetoprotein level (<5.0 ng/ml) was an independent predictor of sustained virologic response (odds ratio = 1.83; 95% confidence interval 1.05-3.20). Serum alpha-fetoprotein measurement should be integrated in the pretreatment assessment of prognostic factors of a virologic response.     

拉米夫定耐药后联合阿德福韦酯治疗发生再耐药的慢性乙型肝炎患者的基因型及耐药位点分析

目的研究拉米夫定(LAM)耐药后联合阿德福韦酯(ADV)抗病毒治疗中发生病毒学突破的慢性乙型肝炎(CHB)患者的耐药位点和基因分型。方法收集2010年6月-2013年6月河南省人民医院收治的89例单用LAM耐药后,联合ADV抗病毒治疗的CHB患者的血清,应用实时定量PCR进行HBV拷贝检测,通过测序进行基因分型,并对rt N236T、rt A181V、rt M204V、rt L180M耐药位点进行检测。计量资料组间比较采用t检验,计数资料组间比较采用χ2检验。结果 89例患者单用LAM治疗后均发生LAM rt M204V位点突变,联合ADV治疗后,9例发生ADV rt N236T单位点突变,5例发生ADV rt A181V单位点突变,8例发生rt A181V+rt N236T双位点联合突变,累计ADV耐药率为24.7%(22/89)。89例患者的HBV基因分型中,C基因型82例,其中8例发生rt A181V+rt N236T双位点联合突变;B基因型7例。结论与B基因型相比,C基因型CHB患者单用LAM耐药后,联合ADV治疗中更易发生rt A181V+rt N236T双位点联合突变。     

Optimizing the clinical application of cardiopulmonary exercise testing in patients with heart failure

Cardiopulmonary exercise testing (CPX) is a well-accepted evaluation technique in patients with heart failure (HF). Even so, interpretation of the wealth of data obtained from CPX remains a challenge. The body of evidence demonstrating the clinical value of CPX in HF point toward several key variables that should be assessed in each patient. These variables include ventilatory efficiency, aerobic capacity, expired carbon dioxide and heart rate recovery. Furthermore, a simple clinical evaluation form, prompting the assessment of key variables, has yet to be developed. The purpose of the present clinical case study in a patient with HF is to highlight key CPX variables and propose a clinical evaluation form.     

Early virologic response to treatment with peginterferon alfa-2b plus ribavirin in patients with chronic hepatitis C

Interferon-based regimens for the treatment of chronic hepatitis C have become increasingly effective and are able to eradicate virus in more than one half of cases. Early identification of patients who will not respond is desirable because treatment might be stopped, thereby avoiding the expense and inconvenience of unnecessary therapy. We examined the accuracy of different degrees of viral inhibition during the early weeks of treatment (early virologic response [EVR]) with pegylated interferon alfa-2b and ribavirin (PEG/R) in identifying patients who would not respond to therapy. The best definition of EVR was a reduction in hepatitis C virus (HCV) RNA by at least 2 logs after the first 12 weeks of treatment compared with baseline. Between 69% and 76% of patients achieved this threshold, depending on the treatment regimen, and sustained virologic response (SVR) occurred in 67% to 80% of these patients. Patients who did not reach EVR did not respond to further therapy. If treatment had been stopped in patients without EVR, drug costs would have been reduced by more than 20%. In conclusion, early confirmation of viral reduction following initiation of antiviral therapy for chronic hepatitis C is worthwhile. It provides a goal to motivate adherence during the first months of therapy and a milepost at which to reassess the need for continued treatment. Most patients who are able to complete the first 12 weeks of therapy achieve EVR and have a high probability of SVR. Patients who fail to achieve EVR will not clear virus even if an additional 9 months of therapy is received. Therapy can be confidently discontinued in those cases.     

Effects of treatment intensification with hydroxyurea in HIV-infected patients with virologic suppression

BACKGROUND: Virologic rebound can result from suboptimal antiviral potency in combination antiretroviral therapy. DESIGN: Multicenter, partially blinded, prospective, randomized study of 202 HIV-infected subjects to determine whether therapy intensification improves long-term rates of virologic suppression. METHODS: Subjects had plasma HIV RNA < 200 copies/ml, CD4 cell count of > 200 x 10(6) cells/l, and treatment with indinavir (IDV) + zidovudine (ZDV) + lamivudine (3TC) for at least 6 months before randomization to stay on this regimen or to receive IDV + didanosine (ddI) + stavudine (d4T) plus or minus hydroxyurea (HU) (600 mg twice daily). Treatment failure was defined as either confirmed rebound of HIV RNA level to > 200 copies/ml or a drug toxicity necessitating treatment discontinuation. RESULTS: Treatment failure occurred more frequently in subjects randomized to the HU-containing arm (32.4%), than in those taking IDV + ddI + d4T (17.6%) or IDV + ZDV + 3TC (7.6%). The time to treatment failure was shorter for the HU-containing arm compared with the IDV + ZDV + 3TC (P < 0.0001) or IDV + ddI + d4T arms (P = 0.032). Dose-limiting toxicities rather than virologic rebound accounted for the differences between treatment failure among the study arms. Pancreatitis led to treatment discontinuation in 4% of subjects in treatment arms containing ddI + d4T. Three subjects with pancreatitis died, all randomized to the HU-containing arm. CONCLUSIONS: Switching to IDV + ddI + d4T + HU in patients treated with IDV + ZDV + 3TC was associated with a worse outcome, principally because of drug toxicity.