The European Exenatide study of long-term exenatide vs. glimepiride for type 2 diabetes: rationale and patient characteristics

AIM

To describe the rationale for the European Exenatide (EUREXA) clinical study and describe the characteristics of the patient cohort.

METHODS

EUREXA is a multinational study of long-term effects of add-on exenatide vs. glimepiride in patients with type 2 diabetes and failure of diet/lifestyle plus metformin monotherapy. Metformin failure was defined as hemoglobin A1c (HbA1c) > or = 6.5% and patients were overweight/obese (BMI > or = 25 to < 40 kg/m(2)). The primary end point is time to failure of combination treatment, defined from HbA1c concentration according to current criteria. At baseline, an oral glucose tolerance test (OGTT) was performed, fasting blood was taken for lipid profile and patients were randomized to add-on exenatide (5 microg b.i.d. for 4 weeks then 10 microg b.i.d.) or glimepiride (1 mg/day titrated to maximum dose).

RESULTS

A total of 1039 patients were entered in the study, with mean (+/- s.d.) age 57.2 +/- 9.6 years, body mass index (BMI) 32.4 +/- 4.1 kg/m(2), duration of diabetes 5.6 +/- 4.5 years and HbA1c 7.4 +/- 0.7%. A history of cardiovascular disease (CVD) was present for 64.8% of patients overall and duration of diabetes was statistically significantly longer for patients with CVD than without (p = 0.010). Lipid abnormalities were reported for 48.9% of patients and 40.9% were taking at least one lipid-lowering medication.

CONCLUSION

Patients included in the EUREXA study had early failure of glucose control with metformin and presented typical features of type 2 diabetes: overweight/obesity and high prevalence of lipid abnormalities and CVD. In this population, the effects of exenatide vs. glimepiride will be evaluated over at least 2.5 years.

Effects of prednisone on blood lactate concentrations in healthy dogs

BACKGROUND

Glucocorticoids affect carbohydrate and lactate metabolism.

HYPOTHESIS

Administration of prednisone to healthy dogs will result in clinically relevant hyperlactatemia.

ANIMALS

Twelve healthy adult Beagle dogs.

METHODS

Prospective, controlled experimental study. Twelve healthy adult Beagles were divided into 2 groups (3 of each sex per group). One group served as control. The other group received 2 treatments: low, 1 mg/kg prednisone PO q24h for 2 weeks; high, 4 mg/kg prednisone PO q24h for 2 weeks. A washout period of 6 weeks separated the treatments. Blood samples were drawn for whole blood lactate measurement on day (D) 0, D4, and D14 and measured in duplicate.

RESULTS

Compared with the control group, low and high groups had significantly higher blood lactate concentrations at D4 and D14. There was no difference at D0. There was no effect of time within the control group. In the low and high groups, blood lactate concentration was increased at D4 and D14 versus D0. Blood lactate concentration was greater in the high group than the low group at D14 only.

CONCLUSIONS AND CLINICAL IMPORTANCE

Dogs treated with prednisone experience statistically significant increases in blood lactate concentrations, which can result in type B hyperlactatemia. In such cases, improving tissue perfusion, treatment for the commonest form of hyperlactatemia (type A) would be unnecessary.

The pro-apoptotic K-Ras 4A proto-oncoprotein does not affect tumorigenesis in the ApcMin/+ mouse small intestine

Background

Alterations in gene splicing occur in human sporadic colorectal cancer (CRC) and may contribute to tumour progression. The K-ras proto-oncogene encodes two splice variants, K-ras 4A and 4B, and K-ras activating mutations which jointly affect both isoforms are prevalent in CRC. Past studies have established that splicing of both the K-ras oncogene and proto-oncogene is altered in CRC in favour of K-ras 4B. The present study addressed whether the K-Ras 4A proto-oncoprotein can suppress tumour development in the absence of its oncogenic allele, utilising the Apc^Min/+ (Min) mouse that spontaneously develops intestinal tumours that do not harbour K-ras activating mutations, and the K-ras^{tmΔ4A/tmΔ4A} mouse that can express the K-ras 4B splice variant only. By this means tumorigenesis in the small intestine was compared between Apc^Min/+, K-ras^+/+ and Apc^Min/+, K-ras^{tmΔ4A/tmΔ4A} mice that can, and cannot, express the K-ras 4A proto-oncoprotein respectively.

Methods

The relative levels of expression of the K-ras splice variants in normal small intestine and small intestinal tumours were quantified by real-time RT-qPCR analysis. Inbred (C57BL/6) Apc^Min/+, K-ras^+/+ and Apc^Min/+, K-ras^{tmΔ4A/tmΔ4A} mice were generated and the genotypes confirmed by PCR analysis. Survival of stocks was compared by the Mantel-Haenszel test, and tumour number and area compared by Student's t-test in outwardly healthy mice at approximately 106 and 152 days of age. DNA sequencing of codons 12, 13 and 61 was performed to confirm the intestinal tumours did not harbour a K-ras activating mutation.

Results

The K-ras 4A transcript accounted for about 50% of K-ras expressed in the small intestine of both wild-type and Min mice. Tumours in the small intestine of Min mice showed increased levels of K-ras 4B transcript expression, but no appreciable change in K-ras 4A transcript levels. No K-ras activating mutations were detected in 27 intestinal tumours derived from Min and compound mutant Min mice. K-Ras 4A deficiency did not affect mouse survival, or tumour number, size or histopathology.

Conclusion

The K-Ras 4A proto-oncoprotein does not exhibit tumour suppressor activity in the small intestine, even though the K-ras 4A/4B ratio is reduced in adenomas lacking K-ras activating mutations.

Efficacy of tadalafil once daily in men with diabetes mellitus and erectile dysfunction

AIMS

Erectile dysfunction (ED) is a common comorbidity in men with diabetes mellitus. Tadalafil 10 or 20 mg taken on demand is efficacious and safe for men with diabetes and ED. Recently, continuous treatment with tadalafil has been proposed, addressing ED management as any other chronic condition. This study examined whether once-daily tadalafil 2.5 and 5 mg is efficacious for men with diabetes and ED.

METHODS

This randomized, double-blind, placebo-controlled, multicentre, 12-week study enrolled 298 men with diabetes and ED to once-daily treatment with placebo, tadalafil 2.5 mg or tadalafil 5 mg. Primary efficacy measures were International Index of Erectile Function Erectile Function (IIEF EF) Domain score, and patient success rates for vaginal penetration and completion of intercourse. Patient satisfaction, endothelial function biomarkers, and safety were also assessed.

RESULTS

Patients receiving either dose of tadalafil had clinically and statistically significant improvements in IIEF EF and statistically significant improvements in mean success rates for vaginal penetration, completion of intercourse, and overall treatment satisfaction (P < or = 0.005 tadalafil vs. placebo, all measures). Endothelial dysfunction biomarkers were unchanged. The most common adverse events were headache, back pain and dyspepsia.

CONCLUSIONS

In this first study of men with diabetes and ED, once-daily tadalafil 2.5 and 5 mg was efficacious and well tolerated, suggesting this may be an alternative to on-demand treatment for some men, eliminating the need to plan sex within a limited timeframe.

Effects on kidney disease, fertility and development in mice inheriting a protein-truncating Denys-Drash syndrome allele (Wt1tmT396)

Denys-Drash syndrome (DDS) is caused by heterozygous mutations of the Wilms' tumour suppressor gene, WT1, characterised by early-onset diffuse mesangial sclerosis often associated with male pseudohermaphroditism and/or Wilms' tumourigenesis. Previously, we reported that the Wt1tmT396 allele induces DDS kidney disease in mice. In the present study heterozygotes (Wt1tmT396/+) were generated on inbred (129/Ola), crossbred (B6/129) and MF1 second backcross (MF1-N2) backgrounds. Whereas male heterozygotes on each background were fertile, inbred heterozygous females were infertile. Kidney disease (proteinuria and sclerosis) was not congenital and developed significantly earlier in inbred mice, although with variable onset. Disease onset in MF1-N2 stocks occurred later in Wt1tmT396/+ mice than reported previously for Wt1R394W/+ mice, and while no kidney disease has been reported in B6/129 Wt1+/- mice, B6/129 Wt1tmT396/+ mice were affected. Offspring of both male and female B6/129 and MF1-N2 Wt1tmT396/+ mice developed kidney disease, but its incidence was significantly higher in offspring of female heterozygotes. Wt1tmT396/tmT396 embryos exhibited identical developmental abnormalities to those reported for Wt1-/- embryos. The results indicate that the Wt1 (tmT396) allele does not predispose to Wilms' tumourigenesis or male pseudohermaphroditism, its effect on kidney disease and female fertility depends on genetic background, stochastic factors may affect disease onset, and disease transmission is subject to a partial parent-of-origin effect. Since the Wt1tmT396 allele has no detectable intrinsic functional activity in vivo, and kidney disease progression is affected by the type of Wt1 mutation, the data support the view that DDS nephropathy results from a dominant-negative action rather than WT1 haploinsufficiency or gain-of-function.

Critical care nursing education and practice in Canada and Australia: a comparative review

Critical care nursing is an area of policy concern with respect to staffing projections, skill mix and educational preparation in both Canada and Australia. Despite many similarities between the health systems of these two countries, differences exist in both undergraduate and graduate specialty nursing education. In Australia, specialist education is primarily delivered via the tertiary sector as a formalised qualification, whereas the current Canadian model displays significant variation in duration, content, and mode of delivery. This paper provides a comparative perspective on the educational preparation of critical care nurses in these two countries. Consideration of alternative models of specialty nursing education may provide a method to improve recruitment and retention of staff while maintaining quality of care.

Dermatological toxicities of panitumumab in the treatment of patients with metastatic colorectal cancer (mCRC) from three clinical studies

14551

Introduction: Epidermal growth factor receptor (EGFr) expression in CRC is associated with metastatic potential and poor prognosis. Panitumumab, a fully human monoclonal antibody against EGFr, was approved for the treatment of patients with refractory mCRC. The main side effects of panitumumab include dermatological manifestations that have been termed “rash”. However, classification of the dermatological manifestations has not been clearly described. Methods: We summarized the dermatological manifestations of 19 patients from 3 clinical studies investigating the the safety and efficacy of panitumumab monotherapy in mCRC in a single institution. Two of these studies were open lable, phase 2 in design which enrolled patients with documented disease progression (PD) during or after adequate doses of fluoropyrimidine, irinotecan, and oxaliplatin chemotherapy. In the other panitumumab was given in combination with irinotecan or oxaliplatin with bevacuzumab, 5FU, and leucovorin. Pts received panitumumab at 6mg/kg Q2W until PD or intolerability. Skin assessments were made q2w. Results: Five patients were men (26%) and 14 (73%) women; 12 were Caucasian (63%) and 7 (36%) African American. The median age was 53 (Range 38–80). Tumor response, disease control, and skin manifestations did not correlate with tumor EGFr levels as assessed by immunohisxtochemistry (Dako EGFR pharmDxtm). No enhancement of skin toxicity was observed when panitumumab was combined with chemotherapy. The median number of cycles received was 11 (Range 3–20). All pts experienced erythema; 17 macular/papular; 13 pustular; 18 acneiform rash; 15 pruritis; 3 honey crusting; 15 dry/flaking; 11 paronychia; 9 hirsuitism; 9 trichomegaly; and all 7 African American patients had significant hyperpigmentation. Photograph illustrations of each category and severity will be presented. Conclusion: Rash associated with panitumumab is common and can be classified according to the clinical dermatological manifestations; specific treatment strategies should be developed and evaluated accordingly. This is the first report of hirsuitism in women and hyperpigmentation in African Americans.

[Table: see text]

Phase I study of topotecan (T) with weekly 5-fluorouracil (5FU)/leucorin (LV) in patients with advanced malignancies

13018

Background: Topotecan (T) is a semi-synthetic camptothecin analog with a broad spectrum of activity targeting the nuclear enzyme topoisomerase I. Daily iv schedules (up to 5) can result in dose limiting neutropenia. Reported synergy in vitro between topoisomerase I inhibitor and 5 FU/LV led us to explore a weekly schedule of 5FU, LV, and T in refractory tumors. Methods: Entry criteria: metastatic or locally advanced solid tumors; up to two prior chemotherapy regimens; prior adjuvant regimen admissible; no chemotherapy or radiation therapy within 4 weeks; adequate hepatic, hematologic, renal function. Exclusion: active second malignancy; CNS metastases; prior topotecan; allergy to related agents; active uncontrolled infection or conditions that would interfere with the study. Treatment was administered days 1, 8, 15, 22 of a 42 day cycle as LV 20 mg/meter (m)2 over 15 minutes intravenously (iv), 5 FU 400mg/m2 bolus, iv, and T at the specified dose (1.5mg/m2, 1.75, 2.0, up to 4 mg) over 30 minutes iv. Cohorts were advanced after at least three pts had completed 42 d. Study is reported through cohort 9: 5 FU 400/m2, LV 20/m2, topotecan 4 mg/m2. Results: Pt characteristics: 19 F, 25 M; ages 29–80, median 62. Tumor types: Pancreas (9), colorectal (6), lung (6), liver (3), salivary gland (5), sinus (2), nasopharynx (2) esophagus (2), and tongue, larynx, ovary granulosa cell tumor (gct), endometrium, mixed mullerian, mesothelioma, sarcoma, gastric (1 each). Related toxicities: gr 3/4 neutropenia 9%/2%, Hb 11%/0, platelets 4.5%/0, fatigue 4.5%/0. Stable disease of ≥ 4 cycles was observed in 18%: pancreas (2), ovarian (1), endometrium (1), salivary gland (3) (2 adenoid cystic, 1 adenocarcinoma). Conclusions: 5 FU, LV and T is well tolerated as a weekly out patient schedule (4 of 6 wks). It achieved minor response in one patient with gct for 8+ cycles and stable disease for ≥ 4 cycles in 6 pts. It is worthy of further exploration for gynecologic, salivary gland and pancreatic cancers.

No significant financial relationships to disclose.

Update in computer-driven weaning from mechanical ventilation

Weaning from mechanical ventilation is a complex process requiring assessment and interpretation of both objective and subjective clinical parameters. For many years, automated computerised systems for various medical processes, including respiratory management, have been proposed to optimise decision-making and reduce variation amongst clinicians. SmartCare/PS, available since 2003 as a software application for the EvitaXL ventilator (Dräger Medical AG & Co. KG, Lübeck, Germany), is one of the first such ventilator systems to be made commercially available. SmartCare/PS can be described as a knowledge-based weaning system, which adjusts pressure support based on measurement of the patient's respiratory status, specifically the spontaneous respiratory rate, tidal volume and end-tidal carbon dioxide with the aim of optimising the weaning process. The primary proposed advantage of this system is an ability to provide management of ventilatory weaning through continuous physiological monitoring and real-time interventions. The relatively small number of available clinical studies indicate the system is able to deliver appropriate ventilation during pressure support weaning from both short-term and prolonged ventilation. Of potential clinical note, a recent study suggested that use of SmartCare/PS might be associated with useful reductions in the duration of weaning compared to existing clinical practice using weaning protocols. One recently published randomised trial supports this conclusion. However, given the known large variation in international critical care ventilatory practices further randomised trials are desirable.

The role of intra-luteal factors in the control of the porcine corpus luteum

In this paper we review three intra-luteal factors and their roles in the corpus luteum (CL). Insulin-like growth factor (IGF)-I, together with its receptor and IGF-binding proteins (IGFBPs), represent an important control system in the CL. IGF-I is a product of small luteal cells and has steroidogenic (i.e. luteotrophic) actions on large luteal cells via the type I receptor, while IGFBPs (e.g. BP-2 and 3; small cells) generally inhibit IGF-Is actions. IGF-I is particularly important in early CL development (up to day 7 of the oestrous cycle) in the pig. Tumour necrosis factor (TNF)-alpha is a product of luteal macrophages that infiltrate CLs in increasing numbers as the cycle progresses. TNF-alpha has been shown to play an important role in luteolysis, but we hypothesise that in the pig, this factor plays an additional role during the mid-luteal phase (days 7-13) in promoting the acquisition of luteal sensitivity to the luteolytic actions of prostaglandin (PG)F2alpha (= luteolytic sensitivity; LS). Endothelin (ET)-1 is a product of (luteal) endothelial cells, and along with its receptors (ETA and ETB) and endothelin-converting enzyme (ECE)-1, represent an intra-luteal system that also plays a role in luteolysis, in association with PGF2alpha. Since TNF-alpha induces endothelial cells to secrete ET-1, we hypothesise that ET-1 mediates the sensitising effects of TNF-alpha on the porcine CL during the mid-luteal phase (days 7-13). Finally, we hypothesise that TNF-alpha and/or ET-1 act to up-regulate luteal protein kinase C (e.g. isoforms betaII and epsilon) activity and thereby sensitises luteal cells to PGF2alpha.

The K-Ras 4A isoform promotes apoptosis but does not affect either lifespan or spontaneous tumor incidence in aging mice

Ras proteins function as molecular switches in signal transduction pathways, and, here, we examined the effects of the K-ras4A and 4B splice variants on cell function by comparing wild-type embryonic stem (ES) cells with K-ras(tmDelta4A/tmDelta4A) (exon 4A knock-out) ES cells which express K-ras4B only and K-ras(-/-) (exons 1-3 knock-out) ES cells which express neither splice variant, and intestinal epithelium from wild-type and K-ras(tmDelta4A/tmDelta4A) mice. RT-qPCR analysis found that K-ras4B expression was reduced in K-ras(tmDelta4A/tmDelta4A) ES cells but unaffected in small intestine. K-Ras deficiency did not affect ES cell growth, and K-Ras4A deficiency did not affect intestinal epithelial proliferation. K-ras(tmDelta4A/tmDelta4A) and K-ras(-/-) ES cells showed a reduced capacity for differentiation following LIF withdrawal, and K-ras(-/-) cells were least differentiated. K-Ras4A deficiency inhibited etoposide-induced apoptosis in ES cells and intestinal epithelial cells. However, K-ras(tmDelta4A/tmDelta4A) ES cells were more resistant to etoposide-induced apoptosis than K-ras(-/-) cells. The results indicate that (1) K-Ras4A promotes apoptosis while K-Ras4B inhibits it, and (2) K-Ras4B, and possibly K-Ras4A, promotes differentiation. The findings raise the possibility that alteration of the K-Ras4A/4B isoform ratio modulates tumorigenesis by differentially affecting stem cell survival and/or differentiation. However, K-Ras4A deficiency did not affect life expectancy or spontaneous overall tumor incidence in aging mice.

Interleukin-17 family and IL-17 receptors

Interleukin-17 (IL-17) is a pro-inflammatory cytokine secreted by activated T-cells. Recently discovered related molecules are forming a family of cytokines, the IL-17 family. The prototype member of the family has been designated IL-17A. Due to recent advances in the human genome sequencing and proteomics five additional members have been identified and cloned: IL-17B, IL-17C, IL-17D, IL-17E and IL-17F. The cognate receptors for the IL-17 family identified thus far are: IL-17R, IL-17RH1, IL-17RL (receptor like), IL-17RD and IL-17RE. However, the ligand specificities of many of these receptors have not been established. The IL-17 signaling system is operative in disparate tissues such as articular cartilage, bone, meniscus, brain, hematopoietic tissue, kidney, lung, skin and intestine. Thus, the evolving IL-17 family of ligands and receptors may play an important role in the homeostasis of tissues in health and disease beyond the immune system. This survey reviews the biological actions of IL-17 signaling in cancers, musculoskeletal tissues, the immune system and other tissues.

Interleukin-17 family and IL-17 receptors

Interleukin-17 (IL-17) is a pro-inflammatory cytokine secreted by activated T-cells. Recently discovered related molecules are forming a family of cytokines, the IL-17 family. The prototype member of the family has been designated IL-17A. Due to recent advances in the human genome sequencing and proteomics five additional members have been identified and cloned: IL-17B, IL-17C, IL-17D, IL-17E and IL-17F. The cognate receptors for the IL-17 family identified thus far are: IL-17R, IL-17RH1, IL-17RL (receptor like), IL-17RD and IL-17RE. However, the ligand specificities of many of these receptors have not been established. The IL-17 signaling system is operative in disparate tissues such as articular cartilage, bone, meniscus, brain, hematopoietic tissue, kidney, lung, skin and intestine. Thus, the evolving IL-17 family of ligands and receptors may play an important role in the homeostasis of tissues in health and disease beyond the immune system. This survey reviews the biological actions of IL-17 signaling in cancers, musculoskeletal tissues, the immune system and other tissues.

[Comparison between line immunoassay (LIA) and enzyme-linked immunosorbent assay (ELISA) for the determination of antibodies to extractable nuclear antigenes (ENA) with reference to other laboratory results and clinical features]

INTRODUCTION

The line immunoassay (LIA) for the determination of antibodies to individual extractable antinuclear antigens (ENA) is a development of the enzyme-linked immunosorbent assay (ELISA) in which the antigens to be tested are adsorbed onto a nylon test strip. In addition, the antigen subspecificities B/B' and D in the case of Sm, the 70 kD, A and C components in the case of U1-snRNP and the Ro52 and Ro60 components in the case of SSA/Ro are present separately on the strips. The aim of the study was to determine whether the line immunoassay is suitable for routine laboratory use by means of a comparison with the ELISA.

METHODS

Sera from 92 patients stored in our serum bank with known ENA profile as determined by ELISA and with at least one antibody to ENA were tested again with LIA. The clinical features and other available laboratory data taken from the patient records were used to classify the disease according to the relevant diagnostic criteria. In discrepant cases, antibodies to ENA were also determined by Western blot. These data were used to determine which of the two methods gave the more plausible results and to calculate the sensitivity and specificity for each autoantibody.

RESULTS

There was good correlation between the two methods, especially for anti-CENP-B (centromere protein B) and anti-Jo1 (histidyl-tRNA transferase) antibodies. For anti-Sm, there was a trend toward higher specificity with the LIA in patients with systemic lupus erythematosus (SLE) if antibodies to Sm D were detected. The LIA was significantly more specific for the detection of antibodies to ribonucleoprotein (RNP) in mixed connective tissue disease and, if antibodies to the 70 kD component were present, also in SLE, although the sensitivity was significantly lower in this case. For anti-SSA/Ro, the specificity of the LIA was significantly higher than ELISA if anti-Ro60 was detected. In the case of anti-SS-B/La, anti-Scl70 (topoisomerase I), anti-CENP-B (centromere protein B) und anti-Jo-1 (histidyl-tRNA transferase), the sensitivity and specificity of the two methods were not significantly different. The LIA was significantly more specific but less sensitive for the detection of anti histone antibodies.

CONCLUSION

The suitability of the LIA for routine laboratory determinations was confirmed.

["Freud and fetichism": previously unpublished minutes of the Vienna Psychoanalytic Society]

On the occasion of this session held by the Viennese Psychoanalytic Society on the 24th of February 1909, Freud made a presentation on fetchism that was the point of departure for a reflection that led him to the theorization of the article of 1927. Being careful to differentiate his position from that of other authors having shown an interest for the subject, he clearly stressed the role of infantile sexuality as an etiological factor, and in particular the link between fetichism and repression. The discussion that followed the presentation shows that Freud and Adler's positions were beginning to diverge, the latter replacing the notion of instincts that Freud held to be involved in the mechanism of repression, by that of "fear of degradation" and of "sensitivity". These Minutes that had been thought to have disappeared are studied within the more general framework of the meetings of the Viennese Psychoanalytic Society.

Endurance, pain and resumption in fully flexed postures

In this study effects of low loads in fully flexed postures were investigated. Thirteen men who were unused to the postures participated. Thirteen professional construction workers with long experience of suchlike postures were also studied. Pain reactions during and after loading were observed, as well as endurance time and the recovery process, here by studying the resumption time. Endurance and resumption times differed little from those given by models used for more common postures. Pain from the legs and not from the back limited the working ability in 86% of the endurance tests. Thirdly, the construction workers had significantly longer endurance time and shorter resumption time.

Safety and bactericidal activity of rifalazil in patients with pulmonary tuberculosis

Rifalazil, also known as KRM-1648 or benzoxazinorifamycin, is a new semisynthetic rifamycin with a long half-life of approximately 60 h. Rifalazil has potent bactericidal activity against Mycobacterium tuberculosis in vitro and in animal models of tuberculosis (TB). Prior studies in healthy volunteers showed that once-weekly doses of 25 to 50 mg of rifalazil were well tolerated. In this randomized, open-label, active-controlled phase II clinical trial, 65 subjects with sputum smear-positive pulmonary TB received one of the following regimens for the first 2 weeks of therapy: 16 subjects received isoniazid (INH) (5 mg/kg of body weight) daily; 16 received INH (5 mg/kg) and rifampin (10 mg/kg) daily; 17 received INH (5 mg/kg) daily plus 10 mg of rifalazil once weekly; and 16 received INH (5 mg/kg) daily and 25 mg of rifalazil once weekly. All subjects were then put on 6 months of standard TB therapy. Pretreatment and day 15 sputum CFU of M. tuberculosis were measured to assess the bactericidal activity of each regimen. The number of drug-related adverse experiences was low and not significantly different among treatment arms. A transient decrease in absolute neutrophil count to less than 2,000 cells/mm(3) was detected in 10 to 20% of patients in the rifalazil- and rifampin-containing treatment arms without clinical consequences. Decreases in CFU counts were comparable among the four treatment arms; however, the CFU results were statistically inconclusive due to the variability in the control arms. Acquired drug resistance did not occur in any patient. Studies focused on determining a maximum tolerated dose will help elucidate the full anti-TB effect of rifalazil.