Long-acting cabotegravir and rilpivirine dosed every 2 months in adults with HIV-1 infection: 152-week results from ATLAS-2M, a randomized, open-label, Phase 3b, noninferiority study

BACKGROUND

Cabotegravir (CAB) + rilpivirine (RPV) dosed intramuscularly monthly or every 2 months is a complete long-acting (LA) regimen for the maintenance of HIV-1 virologic suppression. Here, we report the ATLAS-2M study Week 152 results.

METHODS

ATLAS-2M is a Phase 3b, randomized, multicenter study assessing the efficacy and safety of CAB+RPV LA every 8 weeks (Q8W) vs. every 4 weeks (Q4W). Virologically suppressed (HIV-1 RNA <50 copies/mL) individuals were randomized to receive CAB+RPV LA Q8W or Q4W. Endpoints included the proportion of participants with plasma HIV-1 RNA ≥50 copies/mL and <50 copies/mL, incidence of confirmed virologic failure (CVF; two consecutive measurements of ≥200 copies/mL), safety, and tolerability.

RESULTS

1045 participants received CAB+RPV LA (Q8W, n=522; Q4W, n=523). CAB+RPV LA Q8W demonstrated noninferior efficacy vs. Q4W dosing, with 2.7% (n=14) and 1.0% (n=5) of participants having HIV-1 RNA ≥50 copies/mL, respectively. The adjusted treatment difference in proportions was 1.7% (95% CI 0.1 to 3.3), meeting the pre-specified noninferiority threshold of 4%. At Week 152, 87% of participants maintained HIV-1 RNA <50 copies/mL (Q8W, 87% [n=456]; Q4W, 86% [n=449]). Overall, 12 (2.3%) participants in the Q8W arm and two (0.4%) participants in the Q4W arm had CVF. Eight and 10 participants with CVF had treatment-emergent resistance-associated mutations to RPV and integrase inhibitors, respectively. Safety profiles were comparable, with no new safety signals observed since Week 48.

CONCLUSIONS

These data demonstrate the durability of virologic suppression with CAB+RPV LA Q8W or Q4W for ∼3 years, and confirm the long-term efficacy, safety, and tolerability of CAB+RPV LA as a complete regimen for the maintenance of HIV-1 virologic suppression.

Long-acting cabotegravir and rilpivirine dosed every 2 months in adults with HIV-1 infection (ATLAS-2M), 48-week results: a randomised, multicentre, open-label, phase 3b, non-inferiority study

BACKGROUND

Phase 3 clinical studies showed non-inferiority of long-acting intramuscular cabotegravir and rilpivirine dosed every 4 weeks to oral antiretroviral therapy. Important phase 2 results of every 8 weeks dosing, and supportive modelling, underpin further evaluation of every 8 weeks dosing in this trial, which has the potential to offer greater convenience. Our objective was to compare the week 48 antiviral efficacy of cabotegravir plus rilpivirine long-acting dosed every 8 weeks with that of every 4 weeks dosing.

METHODS

ATLAS-2M is an ongoing, randomised, multicentre (13 countries; Australia, Argentina, Canada, France, Germany, Italy, Mexico, Russia, South Africa, South Korea, Spain, Sweden, and the USA), open-label, phase 3b, non-inferiority study of cabotegravir plus rilpivirine long-acting maintenance therapy administered intramuscularly every 8 weeks (cabotegravir 600 mg plus rilpivirine 900 mg) or every 4 weeks (cabotegravir 400 mg plus rilpivirine 600 mg) to treatment-experienced adults living with HIV-1. Eligible newly recruited individuals must have received an uninterrupted first or second oral standard-of-care regimen for at least 6 months without virological failure and be aged 18 years or older. Eligible participants from the ATLAS trial, from both the oral standard-of-care and long-acting groups, must have completed the 52-week comparative phase with an ATLAS-2M screening plasma HIV-1 RNA less than 50 copies per mL. Participants were randomly assigned 1:1 to receive cabotegravir plus rilpivirine long-acting every 8 weeks or every 4 weeks. The randomisation schedule was generated by means of the GlaxoSmithKline validated randomisation software RANDALL NG. The primary endpoint at week 48 was HIV-1 RNA ≥50 copies per mL (Snapshot, intention-to-treat exposed), with a non-inferiority margin of 4%. The trial is registered at ClinicalTrials.gov, NCT03299049 and is ongoing.

FINDINGS

Screening occurred between Oct 27, 2017, and May 31, 2018. Of 1149 individuals screened, 1045 participants were randomised to the every 8 weeks (n=522) or every 4 weeks (n=523) groups; 37% (n=391) transitioned from every 4 weeks cabotegravir plus rilpivirine long-acting in ATLAS. Median participant age was 42 years (IQR 34-50); 27% (n=280) female at birth; 73% (n=763) white race. Cabotegravir plus rilpivirine long-acting every 8 weeks was non-inferior to dosing every 4 weeks (HIV-1 RNA ≥50 copies per mL; 2% vs 1%) with an adjusted treatment difference of 0·8 (95% CI -0·6-2·2). There were eight (2%, every 8 weeks group) and two (<1%, every 4 weeks group) confirmed virological failures (two sequential measures ≥200 copies per mL). For the every 8 weeks group, five (63%) of eight had archived non-nucleoside reverse transcriptase inhibitor resistance-associated mutations to rilpivirine at baseline. The safety profile was similar between dosing groups, with 844 (81%) of 1045 participants having adverse events (excluding injection site reactions); no treatment-related deaths occurred.

INTERPRETATION

The efficacy and safety profiles of dosing every 8 weeks and dosing every 4 weeks were similar. These results support the use of cabotegravir plus rilpivirine long-acting administered every 2 months as a therapeutic option for people living with HIV-1.

FUNDING

ViiV Healthcare and Janssen.

Long-acting cabotegravir and rilpivirine dosed every 2 months in adults with HIV-1 infection (ATLAS-2M), 96-week results: a randomised, multicentre, open-label, phase 3b, non-inferiority study

BACKGROUND

Long-acting cabotegravir and rilpivirine administered monthly or every 2 months might address the challenges associated with daily oral antiretroviral therapy. The ATLAS-2M week 48 results showed non-inferiority of long-acting cabotegravir and rilpivirine administered every 8 weeks compared with that of every 4 weeks. In this study, we report the efficacy, safety, and tolerability results from the week 96 analysis.

METHODS

ATLAS-2M is a randomised, multicentre, open-label, phase 3b, non-inferiority trial conducted in 13 countries, evaluating the safety and efficacy of maintenance treatment with intramuscular injections of long-acting cabotegravir and rilpivirine, administered every 8 weeks versus every 4 weeks, to people living with HIV-1. Virologically suppressed adults with HIV-1, either already receiving intramuscular long-acting cabotegravir and rilpivirine every 4 weeks (ie, ATLAS study rollover participants) or oral standard of care, were randomly assigned (1:1), in an unblinded fashion, to receive either intramuscular long-acting cabotegravir (600 mg) and rilpivirine (900 mg) every 8 weeks (ie, the every 8-week dosing group) or intramuscular long-acting cabotegravir (400 mg) and rilpivirine (600 mg) every 4 weeks (ie, the every 4-week dosing group). Randomisation was generated using the GlaxoSmithKline-validated randomisation software RANDALL NG (version 1.3.3). The primary endpoint at week 48 was the proportion of participants with plasma HIV-1 RNA measurements of 50 copies per mL or more (ie, the US Food and Drug Administration [FDA] Snapshot algorithm), which has been published previously. Here, we present the week 96 results: the proportion of participants with plasma HIV-1 RNA measurements of less than 50 copies per mL (FDA Snapshot algorithm), with a non-inferiority margin of -10%; the proportion of participants with plasma HIV-1 RNA measurements of 50 copies per mL or more (FDA Snapshot algorithm), with a non-inferiority margin of 4%; the proportion of participants with protocol-defined confirmed virological failure (ie, two consecutive plasma HIV-1 RNA measurements ≥200 copies per mL); safety; pharmacokinetics; and tolerability. This study is registered with ClinicalTrials.gov, number NCT03299049, and is currently ongoing.

FINDINGS

Between Oct 27, 2017, and May 31, 2018, a total of 1149 participants were screened; of whom, 1049 (91%) were randomly assigned and 1045 (91%) initiated treatment (522 in the every 8-week dosing group and 523 in the every 4-week dosing group). The median age was 42 years (IQR 34-50). 280 (27%) of 1045 participants were assigned female at birth and 764 (73%) were white. At week 96 (FDA Snapshot algorithm), 11 (2%) of 522 participants in the every 8-week dosing group and six (1%) of 523 in the every 4-week dosing group had an HIV-1 RNA measurement of 50 copies per mL or more, with an adjusted treatment difference of 1·0 (95% CI -0·6 to 2·5), meeting the prespecified non-inferiority threshold of 4%; 475 (91%) of 522 participants in the every 8-week dosing group and 472 (90%) of 523 in the every 4-week dosing group maintained an HIV-1 RNA measurement of less than 50 copies per mL, with an adjusted treatment difference of 0·8 (95% CI -2·8 to 4·3), which met the prespecified non-inferiority threshold of -10%. One participant in the every 8-week dosing group met the confirmed virological failure criterion since the week 48 analysis at week 88, resulting in a total of nine participants in the every 8-week dosing group and two in the every 4-week dosing group having confirmed virological failure. No new safety signals were identified, and no treatment-related deaths occurred. Injection site reactions were the most common adverse event, occurring in 412 (79%) of 522 participants in the every 8-week dosing group and 400 (76%) of 523 in the every 4-week dosing group. Most injection site reactions were grade 1 or 2 (7453 [99%] of 7557 in both groups), with a median duration of 3 days (IQR 2-5).

INTERPRETATION

Long-acting cabotegravir and rilpivirine dosed every 8 weeks had non-inferior efficacy compared with that of every 4 weeks through the 96-week analysis, with both regimens maintaining high levels of virological suppression. These results show the durable safety, efficacy, and acceptability of dosing long-acting cabotegravir and rilpivirine monthly and every 2 months as maintenance therapy for people living with HIV-1.

FUNDING

ViiV Healthcare and Janssen Research & Development.

Intraspecific variation in thermal acclimation and tolerance between populations of the winter ant, Prenolepis imparis

Thermal phenotypic plasticity, otherwise known as acclimation, plays an essential role in how organisms respond to short-term temperature changes. Plasticity buffers the impact of harmful temperature changes; therefore, understanding variation in plasticity in natural populations is crucial for understanding how species will respond to the changing climate. However, very few studies have examined patterns of phenotypic plasticity among populations, especially among ant populations. Considering that this intraspecies variation can provide insight into adaptive variation in populations, the goal of this study was to quantify the short-term acclimation ability and thermal tolerance of several populations of the winter ant, Prenolepis imparis. We tested for correlations between thermal plasticity and thermal tolerance, elevation, and body size. We characterized the thermal environment both above and below ground for several populations distributed across different elevations within California, USA. In addition, we measured the short-term acclimation ability and thermal tolerance of those populations. To measure thermal tolerance, we used chill-coma recovery time (CCRT) and knockdown time as indicators of cold and heat tolerance, respectively. Short-term phenotypic plasticity was assessed by calculating acclimation capacity using CCRT and knockdown time after exposure to both high and low temperatures. We found that several populations displayed different chill-coma recovery times and a few displayed different heat knockdown times, and that the acclimation capacities of cold and heat tolerance differed among most populations. The high-elevation populations displayed increased tolerance to the cold (faster CCRT) and greater plasticity. For high-temperature tolerance, we found heat tolerance was not associated with altitude; instead, greater tolerance to the heat was correlated with increased plasticity at higher temperatures. These current findings provide insight into thermal adaptation and factors that contribute to phenotypic diversity by revealing physiological variance among populations.

Week 48 Resistance Analyses of the Once-Daily, Single-Tablet Regimen Darunavir/Cobicistat/Emtricitabine/Tenofovir Alafenamide (D/C/F/TAF) in Adults Living with HIV-1 from the Phase III Randomized AMBER and EMERALD Trials

Darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg is being investigated in two Phase III trials, AMBER (NCT02431247; treatment-naive adults) and EMERALD (NCT02269917; treatment-experienced, virologically suppressed adults). Week 48 AMBER and EMERALD resistance analyses are presented. Postbaseline samples for genotyping/phenotyping were analyzed from protocol-defined virologic failures (PDVFs) with viral load (VL) ≥400 copies/mL at failure/later time points. Post hoc analyses were deep sequencing in AMBER, and HIV-1 proviral DNA from baseline samples (VL <50 copies/mL) in EMERALD. Through week 48 across both studies, no darunavir, primary PI, or tenofovir resistance-associated mutations (RAMs) were observed in HIV-1 viruses of 1,125 participants receiving D/C/F/TAF or 629 receiving boosted darunavir plus emtricitabine/tenofovir-disoproxil-fumarate. In AMBER, the nucleos(t)ide analog reverse transcriptase inhibitor (N(t)RTI) RAM M184I/V was identified in HIV-1 of one participant during D/C/F/TAF treatment. M184V was detected pretreatment as a minority variant (9%). In EMERALD, in participants with prior VF and genoarchive data (N = 140; 98 D/C/F/TAF and 42 control), 4% had viruses with darunavir RAMs, 38% with emtricitabine RAMs, mainly at position 184 (41% not fully susceptible to emtricitabine), 4% with tenofovir RAMs, and 21% ≥ 3 thymidine analog-associated mutations (24% not fully susceptible to tenofovir) detected at screening. All achieved VL <50 copies/mL at week 48 or prior discontinuation. D/C/F/TAF has a high genetic barrier to resistance; no darunavir, primary PI, or tenofovir RAMs were observed through 48 weeks in AMBER and EMERALD. Only one postbaseline M184I/V RAM was observed in HIV-1 of an AMBER participant. In EMERALD, baseline archived RAMs to darunavir, emtricitabine, and tenofovir in participants with prior VF did not preclude virologic response.

Phase 3 Study of Ibalizumab for Multidrug-Resistant HIV-1

BACKGROUND

Ibalizumab, a humanized IgG4 monoclonal antibody, blocks the entry of human immunodeficiency virus type 1 (HIV-1) by noncompetitive binding to CD4.

METHODS

In this single-group, open-label, phase 3 study, we enrolled 40 adults with multidrug-resistant (MDR) HIV-1 infection in whom multiple antiretroviral therapies had failed. All the patients had a viral load of more than 1000 copies of HIV-1 RNA per milliliter. After a 7-day control period in which patients continued to receive their current therapy, a loading dose of 2000 mg of ibalizumab was infused; the viral load was quantified 7 days later. Through week 25 of the study, patients received 800 mg of ibalizumab every 14 days, combined with an individually optimized background regimen including at least one fully active agent. The primary end point was the proportion of patients with a decrease in viral load of at least 0.5 log₁₀ copies per milliliter from baseline (day 7) to day 14.

RESULTS

A total of 31 patients completed the study. The mean baseline viral load was 4.5 log₁₀ copies per milliliter, and the mean CD4 count was 150 per microliter. Of the 40 patients in the intention-to-treat population, 33 (83%) had a decrease in viral load of at least 0.5 log₁₀ copies per milliliter from baseline (P<0.001 for the comparison with the control period). The mean viral-load decrease was 1.1 log₁₀ copies per milliliter. During the control period, 1 patient, who received the optimized background regimen prematurely, had a decrease in viral load of 0.5 log₁₀ copies per milliliter. At week 25, patients who had received ibalizumab plus an optimized background regimen had a mean decrease of 1.6 log₁₀ copies per milliliter from baseline; 43% of the patients had a viral load of less than 50 copies per milliliter, and 50% had a viral load of less than 200 copies per milliliter. Among 10 patients who had virologic failure or rebound, in vitro testing identified 9 who had a lower degree of susceptibility to ibalizumab than at baseline. The most common adverse event was diarrhea (in 20% of patients). Four patients died from causes related to underlying illnesses; 1 had a serious adverse event (the immune reconstitution inflammatory syndrome) that was deemed to be related to ibalizumab therapy.

CONCLUSIONS

In patients with MDR HIV-1 infection who had advanced disease and limited treatment options, ibalizumab had significant antiviral activity during a 25-week study. Evidence of the emergence of diminished ibalizumab susceptibility was observed in vitro in patients who had virologic failure. (Funded by the Orphan Products Clinical Trials Grants Program of the Food and Drug Administration and TaiMed Biologics; TMB-301 ClinicalTrials.gov number, NCT02475629 .).

Forty-eight-Week Safety and Efficacy On-Treatment Analysis of Ibalizumab in Patients with Multi-Drug Resistant HIV-1

Background

Management of multi-drug-resistant (MDR) HIV-1 remains a challenge. The advent of antiretroviral (ARVs) with novel mechanisms of action are needed to expand therapeutic options for MDR patients. Ibalizumab (IBA) is a humanized monoclonal antibody with a unique binding specificity to the CD4 domain 2, allowing it to block viral entry into host cells without CD4 depletion. Patients completing the 24-week Phase 3 study (TMB-301) continued treatment in study TMB-311. Here, we report the durable efficacy and long-term safety of IBA with an optimized background regimen (OBR) through 48 weeks of treatment.

Methods

TMB-301 was an open-label study investigating the antiviral activity and safety of IBA plus OBR in highly treatment-experienced patients with MDR HIV-1. Patients received an intravenous loading dose of 2,000mg followed by 800mg doses every 2 weeks for 24 weeks. 7 days after loading dose, an OBR was added with at least 1 additional sensitive agent throughout the study. Following completion of the 24-week TMB-301 study, patients continued to receive IBA at 800mg every 2 weeks under TMB-311 for up to 48 weeks. Safety and efficacy were assessed until 48 weeks.

Results

A total of 31 patients enrolled in TMB-301 completed the 24-week treatment period. Of 31 patients, 27 entered study TMB-311. These patients were highly resistant patients - 59% and 33% of patients had exhausted ≥3 and ≥4 ARV classes, respectively, and 7% of patients had HIV-1 resistant to all approved ARVs. IBA plus OBR was well tolerated. Of the 27 patients, 24 (89%) continued to receive treatment until Week 48. The three patients discontinued early due to non IBA-related reasons. No new or unexpected safety concerns emerged between Week 24 and 48. The potent suppression of viremia observed Week 24 was sustained through Week 48. Median viral load (VL) reduction from BL was 2.5 log₁₀ at both Week 24 and 48. Of 27 patients (59%) 16 had VL <50 copies/ml and 17 (63%) patients had VL < 200 copies/ml. All 15 patients with VL < 50 copies/ml at Week 24 maintained viral suppression to Week 48.

Conclusion

IBA plus OBR continued to achieve high rates of virologic suppression through Week 48. The results support the durable efficacy and long-term safety of IBA in highly treatment-experienced MDR patients and offer a valuable treatment option for patients.

Disclosures

B. Emu, TaiMed Biologics: Employee and Shareholder, Salary; P. N. Kumar, TaiMed: Advisory Board and Investigator, Consulting fee and Grant recipient; G. Richmond, TaiMed: Investigator, Research support; S. Weinheimer, TaiMed: Employee, Salary; C. Marsolais, TaiMed: Commercial partner, Salary and Salary from Theratechnologies, commercial partner; S. Lewis, TaiMed: Employee, Salary and Salary from Theratechnologies, commercial partner

Sword 1 and 2: Subgroup Analysis of 48 Week Results by Age, Race and Gender

Background

Switching to the 2-drug regimen (2DR) of DTG+RPV was proven non-inferior to continuing a suppressive PI-, INI- or NNRTI- based current antiretroviral regimen (CAR) at Week 48. This analysis evaluated the efficacy and safety of switching from CAR to DTG+RPV by age, race and gender subgroups.

Methods

Two identically designed, open-label, multicenter, global, phase III, non-inferiority studies compared the efficacy and safety of switching from a 3 or 4-drug CAR to DTG + RPV once daily in HIV-1-infected adults, with HIV-1 RNA&lt;50 c/mL. Primary endpoint was proportion of patients with VL&lt;50 c/mL at Wk48 using FDA Snapshot. Additional analysis were performed to summarize efficacy base on age, race and gender subgroups for each individual study and pooled.

Results

1024 patients were randomized and exposed (DTG+RPV 513; CAR 511), across both studies. Treatment arms were well matched for demographic and baseline characteristics. Median age across both arms was 43.4 years, with 29% and 28% ≥ 50 years in DTG+RPV and CAR, respectively. 23% and 21% were female while 18% and 22% were non-white for DTG+RPV and CAR. For the pooled studies and for SWORD-1 and SWORD-2 individually, switching to DTG+RPV was non-inferior to CAR at Wk48. Similar response rates were observed in the DTG+RPV arm compared with CAR across subgroups (Table 1). More AEs were reported in the DTG+/RPV arm across all subgroups except Asian race; no unexpected AEs were identified for either drug.

Conclusion

Switch to a novel, once daily 2DR of DTG+RPV in patients with a suppressed viral load, was an effective and well tolerated treatment option across age, race, and gender subgroups which were consistent with overall results.

Disclosures

S. Walmsley, Merck: Board Member, Consultant, Grant Investigator, Investigator, Scientific Advisor and Speaker’s Bureau, Consulting fee, Grant recipient, Research grant and Speaker honorarium; ViiV Healthcare: Board Member, Consultant, Grant Investigator, Investigator, Scientific Advisor and Speaker’s Bureau, Consulting fee, Grant recipient, Research grant and Speaker honorarium; Gilead Sciences: Board Member, Consultant, Grant Investigator, Investigator, Scientific Advisor and Speaker’s Bureau, Consulting fee, Grant recipient, Research grant and Speaker honorarium; GSK: Board Member, Consultant, Grant Investigator, Investigator, Scientific Advisor and Speaker’s Bureau, Consulting fee, Grant recipient, Research grant and Speaker honorarium; Janssen: Board Member, Consultant, Grant Investigator, Investigator, Scientific Advisor and Speaker’s Bureau, Grant recipient, Research grant and Speaker honorarium; BMS: Grant Investigator, Investigator, Scientific Advisor and Speaker’s Bureau, Consulting fee, Grant recipient, Research grant and Speaker honorarium; G. Richmond, Viiv Healthcare: Investigator, Research support; &#x2028;

F. Bredeek, ViiV Healthcare: Investigator and Scientific Advisor, Consulting fee and Research support; M. Ramgopal, viiv: Investigator, Consulting fee; C. C. Hung, Gilead Sciences: Board Member and Speaker’s Bureau, Consulting fee and Speaker honorarium; ViiV: Board Member and Investigator, Consulting fee and Research support; Abbvie: Board Member and Investigator, Consulting fee and Research grant; Bristol-Myers Squibb: Investigator, Research support; Jassen: Board Member and Investigator, Consulting fee and Research support; E. Blair, ViiV Healthcare: Employee and Shareholder, Salary; L. Kahl, ViiV Healthcare: Employee and Shareholder, Salary; M. Underwood, ViiV Healthcare: Employee, Salary; K. Angelis, GlaxoSmithKline: Employee, Salary; K. Vandermeulen, Jansen: Employee, Salary; B. Wynne, ViiV Healthcare: Employee, Salary; M. Aboud, ViiV Healthcare: Employee, Salary

Dolutegravir versus raltegravir in antiretroviral-experienced, integrase-inhibitor-naive adults with HIV: week 48 results from the randomised, double-blind, non-inferiority SAILING study

BACKGROUND

Dolutegravir (GSK1349572), a once-daily HIV integrase inhibitor, has shown potent antiviral response and a favourable safety profile. We evaluated safety, efficacy, and emergent resistance in antiretroviral-experienced, integrase-inhibitor-naive adults with HIV-1 with at least two-class drug resistance.

METHODS

ING111762 (SAILING) is a 48 week, phase 3, randomised, double-blind, active-controlled, non-inferiority study that began in October, 2010. Eligible patients had two consecutive plasma HIV-1 RNA assessments of 400 copies per mL or higher (unless >1000 copies per mL at screening), resistance to two or more classes of antiretroviral drugs, and had one to two fully active drugs for background therapy. Participants were randomly assigned (1:1) to once-daily dolutegravir 50 mg or twice-daily raltegravir 400 mg, with investigator-selected background therapy. Matching placebo was given, and study sites were masked to treatment assignment. The primary endpoint was the proportion of patients with plasma HIV-1 RNA less than 50 copies per mL at week 48, evaluated in all participants randomly assigned to treatment groups who received at least one dose of study drug, excluding participants at one site with violations of good clinical practice. Non-inferiority was prespecified with a 12% margin; if non-inferiority was established, then superiority would be tested per a prespecified sequential testing procedure. A key prespecified secondary endpoint was the proportion of patients with treatment-emergent integrase-inhibitor resistance. The trial is registered at ClinicalTrials.gov, NCT01231516.

FINDINGS

Analysis included 715 patients (354 dolutegravir; 361 raltegravir). At week 48, 251 (71%) patients on dolutegravir had HIV-1 RNA less than 50 copies per mL versus 230 (64%) patients on raltegravir (adjusted difference 7·4%, 95% CI 0·7 to 14·2); superiority of dolutegravir versus raltegravir was then concluded (p=0·03). Significantly fewer patients had virological failure with treatment-emergent integrase-inhibitor resistance on dolutegravir (four vs 17 patients; adjusted difference -3·7%, 95% CI -6·1 to -1·2; p=0·003). Adverse event frequencies were similar across groups; the most commonly reported events for dolutegravir versus raltegravir were diarrhoea (71 [20%] vs 64 [18%] patients), upper respiratory tract infection (38 [11%] vs 29 [8%]), and headache (33 [9%] vs 31 [9%]). Safety events leading to discontinuation were infrequent in both groups (nine [3%] dolutegravir, 14 [4%] raltegravir).

INTERPRETATION

Once-daily dolutegravir, in combination with up to two other antiretroviral drugs, is well tolerated with greater virological effect compared with twice-daily raltegravir in this treatment-experienced patient group.

FUNDING

ViiV Healthcare.

Safety and efficacy of dolutegravir in treatment-experienced subjects with raltegravir-resistant HIV type 1 infection: 24-week results of the VIKING Study

Background. Dolutegravir (DTG; S/GSK1349572), a human immunodeficiency virus type 1 (HIV-1) integrase inhibitor, has limited cross-resistance to raltegravir (RAL) and elvitegravir in vitro. This phase IIb study assessed the activity of DTG in HIV-1–infected subjects with genotypic evidence of RAL resistance.

Methods. Subjects received DTG 50 mg once daily (cohort I) or 50 mg twice daily (cohort II) while continuing a failing regimen (without RAL) through day 10, after which the background regimen was optimized, when feasible, for cohort I, and at least 1 fully active drug was mandated for cohort II. The primary efficacy end point was the proportion of subjects on day 11 in whom the plasma HIV-1 RNA load decreased by ≥0.7 log₁₀ copies/mL from baseline or was <400 copies/mL.

Results. A rapid antiviral response was observed. More subjects achieved the primary end point in cohort II (23 of 24 [96%]), compared with cohort I (21 of 27 [78%]) at day 11. At week 24, 41% and 75% of subjects had an HIV-1 RNA load of <50 copies/mL in cohorts I and II, respectively. Further integrase genotypic evolution was uncommon. Dolutegravir had a good, similar safety profile with each dosing regimen.

Conclusion. Dolutegravir 50 mg twice daily with an optimized background provided greater and more durable benefit than the once-daily regimen. These data are the first clinical demonstration of the activity of any integrase inhibitor in subjects with HIV-1 resistant to RAL.

Conformer specific dissociation dynamics of iodocyclohexane studied by velocity map imaging

The photodissociation dynamics of iodocyclohexane has been studied using velocity map imaging following excitation at many wavelengths within its A-band (230 ≤ λ ≤ 305 nm). This molecule exists in two conformations (axial and equatorial), and one aim of the present experiment was to explore the extent to which conformer-specific fragmentation dynamics could be distinguished. Ground (I) and spin-orbit excited (I∗) state iodine atom products were monitored by 2 + 1 resonance enhanced multiphoton ionization, and total kinetic energy release (TKER) spectra and angular distributions derived from analysis of images recorded at all wavelengths studied. TKER spectra obtained at the longer excitation wavelengths show two distinct components, which can be attributed to the two conformers and the different ways in which these partition the excess energy upon C-I bond fission. Companion calculations based on a simple impulsive model suggest that dissociation of the equatorial (axial) conformer preferentially yields vibrationally (rotationally) excited cyclohexyl co-fragments. Both I and I∗ products are detected at the longest parent absorption wavelength (λ ∼ 305 nm), and both sets of products show recoil anisotropy parameters, β > 1, implying prompt dissociation following excitation via a transition whose dipole moment is aligned parallel to the C-I bond. The quantum yield for forming I∗ products, Φ(I∗), has been determined by time resolved infrared diode laser absorption methods to be 0.14 ± 0.02 (at λ = 248 nm) and 0.22 ± 0.05 (at λ = 266 nm). Electronic structure calculations indicate that the bulk of the A-band absorption is associated with transition to the 4A(') state, and that the (majority) I atom products arise via non-adiabatic transfer from the 4A(') potential energy surface (PES) via conical intersection(s) with one or more PESs correlating with ground state products.

ELECTROPHORETIC STUDY OF ANTIVIRAL SERA

1. Sera of animals immunized against Japanese B encephalitis, Venezuelan equine encephalomyelitis, and Western equine encephalomyelitis viruses were fractionated by electrophoresis. 2. Electrophoretic patterns of rabbit sera before and after immunization against Japanese B virus showed no consistent change traceable to antibody formation. 3. To determine the antibody content, the electrophoretic fractions of the respective sera were mixed in varying dilutions with infected mouse brain suspensions, and the neutralizing titers of the fractions were compared. 4. In all instances serum fractions containing γ-globulin were protective, whereas in no case did serum albumin show any virus-neutralizing activity. The Japanese B encephalitis antibody appeared to be associated entirely with the γ-globulin. The Venezuelan and Western equine encephalomyelitis antibodies were associated with the β- and γ-globulins and probably possessed an average electrophoretic mobility between that of β- and γ-globulins. 5. Normal rabbit serum similarly separated electrophoretically showed no neutralizing properties. 6. Chickens, whose electrophoretic serum pattern is markedly different from that of rabbits, were also immunized against the Japanese B encephalitis virus. Their antisera were electrophoretically fractionated and similarly subjected to neutralization tests. The specific neutralizing capacity of chicken serum was considerably lower than that of rabbit serum and no neutralizing activity was found in the fractions containing the faster moving components. The antibody appeared to be associated with component 4 which had a mobility of approximately 2.3 x 10^–5 cm.²/volt/sec.

Safety, pharmacokinetics, and antiviral activity of HGS004, a novel fully human IgG4 monoclonal antibody against CCR5, in HIV-1-infected patients

BACKGROUND

HGS004 is a fully human immunoglobulin (Ig) G4 monoclonal antibody against CC chemokine receptor 5 (CCR5) with robust in vitro activity against a diverse panel of CCR5-tropic human immunodeficiency virus type 1 (HIV-1) isolates.

METHODS

A single-blind, randomized, placebo-controlled study was conducted in patients infected with CCR5-tropic HIV-1 to evaluate the safety, pharmacokinetics, and antiviral activity of HGS004. Sixty-three subjects were randomized into 5 dose cohorts (0.4, 2, 8, 20, and 40 mg/kg) and received a single intravenous dose of HGS004 or placebo.

RESULTS

HGS004 was well tolerated, and no dose-limiting toxicities were observed. Pharmacokinetics were nonlinear across the 0.4-40-mg/kg dose range, with dose-proportional increases in maximum concentration, although the area under the curve increased more than proportionally to dose. High levels of receptor occupancy were observed for up to 28 days in the higher-dose cohorts. Plasma HIV-1 RNA reductions of >1 log(10) at day 14 were observed in 14 (54%) of 26 subjects in the 8-, 20-, and 40-mg/kg cohorts. In the 40-mg/kg cohort, 4 of 10 subjects had a >1 log(10) HIV-1 RNA reduction at day 28. Drug concentrations relative to isolate sensitivity (the ratio of the concentration at day 14 to IC(90)) predicted antiviral response on day 14.

CONCLUSIONS

HGS004 is safe and well tolerated and demonstrates meaningful antiviral activity when administered to patients infected with CCR5-tropic HIV-1.

Metabolic effects of a growth hormone-releasing factor in patients with HIV

BACKGROUND

Visceral adipose tissue accumulates during antiretroviral therapy in many patients who are infected with the human immunodeficiency virus (HIV); this process is associated with an increased cardiovascular risk. We assessed the use of a growth hormone-releasing factor analogue, tesamorelin, to decrease visceral adiposity.

METHODS

We randomly assigned 412 patients with HIV (86% of whom were men) who had an accumulation of abdominal fat to receive a daily subcutaneous injection of either 2 mg of tesamorelin or placebo for 26 weeks. The primary end point was the percent change from baseline in visceral adipose tissue as shown on computed tomography. Secondary end points included triglyceride levels, the ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol, the level of insulin-like growth factor I (IGF-I), and self-assessed body image. Glycemic measures included glucose and insulin levels.

RESULTS

The measure of visceral adipose tissue decreased by 15.2% in the tesamorelin group and increased by 5.0% in the placebo group; the levels of triglycerides decreased by 50 mg per deciliter and increased by 9 mg per deciliter, respectively, and the ratio of total cholesterol to HDL cholesterol decreased by 0.31 and increased by 0.21, respectively (P<0.001 for all comparisons). Levels of total cholesterol and HDL cholesterol also improved significantly in the tesamorelin group. Levels of IGF-I increased by 81.0% in the tesamorelin group and decreased by 5.0% in the placebo group (P<0.001). Adverse events did not differ significantly between the two study groups, but more patients in the tesamorelin group withdrew from the study because of an adverse event. No significant differences were observed in glycemic measures.

CONCLUSIONS

Daily tesamorelin for 26 weeks decreased visceral fat and improved lipid profiles, effects that might be useful in HIV-infected patients who have treatment-associated central fat accumulation. (ClinicalTrials.gov number, NCT00123253 [ClinicalTrials.gov] .).

Recombinant human growth hormone to treat HIV-associated adipose redistribution syndrome: 12 week induction and 24-week maintenance therapy

BACKGROUND

HIV-associated adipose redistribution syndrome (HARS) is an HIV-associated disorder characterized by excess truncal fat, including visceral adipose tissue (VAT).

METHODS

From baseline to week 12 in this randomized, double-blind, placebo (PL)-controlled, multicenter trial investigating effects of recombinant human growth hormone (r-hGH; Serostim; EMD Serono Inc., Rockland, MA) in patients with HARS, 325 received induction (4 mg/d of r-hGH) or PL. At week 12, patients who initially received induction were rerandomized to 2 mg of r-hGH on alternate days (maintenance) or PL to week 36. Patients who initially received PL later received 4 mg/d of r-hGH. Change in VAT was the primary outcome. Key secondary outcomes included changes in non-high-density lipoprotein cholesterol (non-HDL-C) and limb fat.

RESULTS

At week 12, induction therapy resulted in decreased VAT (-32.6 vs. 0.5 cm2; P<0.001), limb fat (-0.4 vs. 0.2 kg; P<0.001), and non-HDL-C (-13.0 vs. -2.8 mg/dL; P=0.023) compared with PL. On r-hGH induction-maintenance (baseline to week 36), patients sustained losses in VAT and trunk fat but not losses of subcutaneous fat in the abdomen or limbs. Also, non-HDL-C remained significantly decreased on r-hGH but not on PL maintenance.

CONCLUSIONS

In patients with HARS, r-hGH induction-maintenance therapy produces greater relative losses of VAT and trunk fat than of subcutaneous fat and also has beneficial effects on the lipid profile.

266 nm photolysis of CF3I and C2F5I studied by diode laser gain FM spectroscopy

Frequency modulated diode laser based absorption at 1.315 microm has been used to measure the Doppler lineshapes of the I((2)P(1/2)-(2)P(3/2)) transition in atomic iodine produced from the 266 nm photolysis of both CF(3)I and C(2)F(5)I. Wavelength resolved laser gain is seen following photolysis as excited iodine atoms ((2)P(1/2)) are produced with a quantum yield close to unity from photolysis of both parent molecules. Time resolved measurements were made and the nascent speed distribution and translational anisotropy parameter, beta were determined. Mean atomic speeds of 800 and 850 ms(-1), which correspond to 83 and 68% of the maximum possible kinetic energy release into the iodine photofragment, were determined for photolysis of CF(3)I and C(2)F(5)I, respectively. The nascent translational anisotropy parameter was found to be beta = 1.77 +/- 0.05 for CF(3)I and beta = 1.69 +/- 0.05 for C(2)F(5)I. These values are explicable in terms of parent rotational motion and non-adiabatic processes in the exit channel.

Pharmacokinetics, pharmacodynamics and safety of once-daily versus twice-daily dosing with enfuvirtide in HIV-infected subjects

OBJECTIVE

To investigate the pharmacokinetics, safety/tolerability and antiviral activity of enfuvirtide administered once-daily (QD) versus twice-daily (BID).

DESIGN

An open-label, randomized, multiple dose, two-period crossover study comparing 180 mg enfuvirtide, two injections QD versus 90 mg enfuvirtide, two injections, BID.

METHODS

Steady-state intensive pharmacokinetic samples were obtained on days 7 and 14.

RESULTS

Thirty-seven subjects received at least one dose of enfuvirtide. Thirty-three subjects completed both dosing periods. The regimens were bioequivalent based on the ratio of geometric mean area under the curve (AUC)0-tau [112 +/- 6.2 microg x h/ml QD; 115 +/- 6.4 microg x h/ml 2 x BID; QD/BID 0.98; 90% confidence interval (CI) 0.89,1.07]. The maximum observed plasma concentration within a dosing interval (Cmax) was 49% higher for QD (9.5 +/- 2.7 microg/ml) versus BID (6.3 +/- 1.7 microg/ml) and the pre-dose plasma concentration (Ctrough) was 57% lower for QD (1.6 +/- 1.1 microg/ml) versus BID (3.8 +/- 1.3 microg/ml). The LSM decrease in viral load from baseline to day 7 was 1.0 +/- 0.14 log10 (n = 18) for QD and 1.4 +/- 0.2 log10 (n = 17) for BID (LSM difference 0.385; P = 0.07). Linear regression analysis suggested that decline in viral load up to day 7 was associated with Ctrough but not Cmax or AUC. There were no significant differences in adverse events between the two dosing regimens.

CONCLUSIONS

Administration of enfuvirtide 180 mg QD results in bioequivalence compared with 90 mg BID based on AUC with a similar short-term safety profile, but a trend towards a weaker antiretroviral effect. Larger and longer-term studies are needed to determine if 180 mg once daily is an effective dosing alternative for enfuvirtide.

A controlled Phase II trial assessing three doses of enfuvirtide (T-20) in combination with abacavir, amprenavir, ritonavir and efavirenz in non-nucleoside reverse transcriptase inhibitor-naive HIV-infected adults

Enfuvirtide is a novel antiretroviral that blocks HIV-1 cell fusion and viral entry. This Phase II, controlled, open-label, randomized, multicentre dose-ranging trial explored the safety, antiviral activity and pharmacokinetics of enfuvirtide, administered by subcutaneous (s.c.) injection, in 71 HIV-1-infected, protease inhibitor-experienced, non-nucleoside reverse transcriptase inhibitor (NNRTI)-naive adults for 48 weeks. Study participants were randomized to receive enfuvirtide at a deliverable dose of 45, 67.5 or 90 mg twice daily; the 45 mg twice daily dose required 2 injections/day, while the higher doses required 4 injections/day. A background oral antiretroviral (ARV) regimen of abacavir (300 mg twice daily), amprenavir (1200 mg twice daily), ritonavir (200 mg twice daily) and efavirenz (600 mg once daily) was provided with enfuvirtide. A control group received the background ARV regimen alone. All potential participants underwent an HIV genotype at screen to ensure a homogenous population and to exclude patients with evidence of genotypic resistance to NNRTIs. Overall, the tolerability of the combination of abacavir, amprenavir, ritonavir, efavirenz and enfuvirtide was generally comparable to control through 48 weeks. No enfuvirtide dose-dependent adverse events (AEs) were observed across treatment groups. Injection site reactions (ISRs) occurred at least once in 68.5% of the enfuvirtide-treated population, and most ISRs were mild to moderate in severity, with no apparent dose relationship. Excluding ISRs, the most common treatment-emergent AEs were nausea, diarrhoea, dizziness and fatigue; with no clinically significant differences in the incidence of AEs observed between the control and enfuvirtide groups. Each treatment group benefited from ARV therapy, with a trend of increasing antiviral and immunological activity associated with increasing enfuvirtide dose. At 48 weeks, the median HIV-1 RNA change from baseline for the ITT population was -2.24 log10 copies/ml for the combined enfuvirtide groups compared with -1.87 log10 copies/ml for the control group. In addition, 54.9% of patients in the enfuvirtide group achieved HIV-1 RNA < or = 400 copies/ml versus 36.8% of patients in the control group. These results indicate that enfuvirtide has a favourable safety profile and is a promising new antiviral agent for HIV-infected patients who have been on previously failing ARV regimens.

A Controlled Phase Ii Trial Assessing Three Doses of Enfuvirtide (T-20) in Combination with Abacavir, Amprenavir, Ritonavir and Efavirenz in Non-Nucleoside Reverse Transcriptase Inhibitor-Naive HIV-Infected Adults

Enfuvirtide is a novel antiretroviral that blocks HIV-1 cell fusion and viral entry. This Phase II, controlled, open-label, randomized, multicentre dose-ranging trial explored the safety, antiviral activity and pharmacoki-netics of enfuvirtide, administered by subcutaneous (SC) injection, in 71 HIV-1-infected, protease inhibitor-experienced, non-nucleoside reverse transcriptase inhibitor (NNRTI)-naive adults for 48 weeks.

Study participants were randomized to receive enfuvirtide at a deliverable dose of 45, 67.5 or 90 mg twice daily; the 45 mg twice daily dose required 2 injections/day, while the higher doses required 4 injections/day. A background oral antiretroviral (ARV) regimen of abacavir (300 mg twice daily), amprenavir (1200 mg twice daily), ritonavir (200 mg twice daily) and efavirenz (600 mg once daily) was provided with enfuvirtide. A control group received the background ARV regimen alone. All potential participants underwent an HIV genotype at screen to ensure a homogenous population and to exclude patients with evidence of genotypic resistance to NNRTIs.

Overall, the tolerability of the combination of abacavir, amprenavir, ritonavir, efavirenz and enfuvirtide was generally comparable to control through 48 weeks. No enfuvirtide dose-dependent adverse events (AEs) were observed across treatment groups. Injection site reactions (ISRs) occurred at least once in 68.5% of the enfuvirtide-treated population, and most ISRs were mild to moderate in severity, with no apparent dose relationship. Excluding ISRs, the most common treatment-emergent AEs were nausea, diarrhoea, dizziness and fatigue; with no clinically significant differences in the incidence of AEs observed between the control and enfuvirtide groups. Each treatment group benefited from ARV therapy, with a trend of increasing antiviral and immunological activity associated with increasing enfuvirtide dose. At 48 weeks, the median HIV-1 RNA change from baseline for the ITT population was –2.24 log10 copies/ml for the combined enfuvirtide groups compared with –1.87 log10 copies/ml for the control group. In addition, 54.9% of patients in the enfuvirtide group achieved HIV-1 RNA ≤400 copies/ml versus 36.8% of patients in the control group.

These results indicate that enfuvirtide has a favourable safety profile and is a promising new antiviral agent for HIV-infected patients who have been on previously failing ARV regimens.

Structure and bonding of molecules at aqueous surfaces

Significant advances toward understanding the structure of aqueous surfaces on a molecular level have been made in recent years. This review focuses on the recent contributions of surface vibrational sum frequency spectroscopy (VSFS) to this field of study. An overview of recent VSFS studies of the molecular structure and orientation of molecules at the vapor-water interface and the interface between water and an immiscible organic liquid is presented, with particular emphasis on studies that compare the molecular properties and adsorbate behavior at these two different but related interfaces. This discussion is preceded by a general introduction to VSFS studies at aqueous surfaces and a description of the fundamental principles underlying the technique.

Plasma clozapine concentrations predict clinical response in treatment-resistant schizophrenia

Steady-state blood clozapine concentrations in 58 schizophrenic patients varied more than 45-fold (40-1911 ng/mL) after fixed-dose treatment (400 mg/day). Discriminant function analysis determined that a blood clozapine concentration of 420 ng/mL optimally distinguished responders from nonresponders. After 4 weeks of treatment, only 8% of those patients with a blood clozapine concentration < 420 ng/mL responded compared with 60% of those who had a blood clozapine concentration > 420 ng/mL. When plasma concentrations were increased above 420 ng/mL (by a double-blind random assignment procedure), nonresponders increased their response rate to 73% if their plasma concentrations at Week 12 exceeded 420 ng/mL compared with a response rate of 29% if their Week 12 levels remained below 420 ng/mL (chi 2 = 4.2, p < .04).

Alterations in the PITSLRE protein kinase gene complex on chromosome 1p36 in childhood neuroblastoma

p58cdc2L1, a protein kinase implicated in apoptotic signaling, is one of eight separate kinases encoded by three tandemly duplicated and linked genes, which we have termed PITSLRE A, B and C. One allele of this complex on chromosome 1 was either deleted or translocated in each of 18 neuroblastoma cell lines with cytogenetically apparent 1p alterations. A protein encoded by this locus, PITSLRE gamma 1, was absent in three of the lines and a smaller, apparently truncated, PITSLRE polypeptide was found in another line. These findings identify a novel gene complex on chromosome 1 that encodes a protein kinase subfamily. We suggest that the PITSLRE locus may harbour one or more tumour suppressor genes affected by chromosome 1p36 modifications in neuroblastoma.

Primary pulmonary hypertension and human immunodeficiency virus infection in a non-hemophiliac man

We describe clinical and postmortem findings in a 44-year-old man with pulmonary hypertension and infection with the human immunodeficiency virus (HIV-1). Plexogenic angiopathy and veno-occlusive lesions were present, in addition to a mild, patchy pulmonary interstitial lymphoid infiltrate. The clinical data for 14 previously reported cases of HIV-associated primary pulmonary hypertension are summarized. We speculate that these vascular changes may be due to damage from a specific immune response to HIV.

Ventromedial hypothalamic lesions and cholinergic control of female sexual behavior

Ovariectomized female rats received bilateral electrolytic or sham lesions of the ventromedial nucleus of the hypothalamus (VMNH). They were tested for sexual receptivity in response to estrogen (EB) and progesterone (P) treatment. Following this they were treated with a small dose of EB and tested for their response to intraventricular microinjection of a muscarinic cholinergic agonist or a vehicle solution. Those animals with lesions involving almost the entire extent of the VMNH displayed an impaired response to EB and P and to the agonist. Lesions which spared 30-50% of the anterior portion of the VMNH did not result in an impairment to EB and P or to the agonist. It is suggested that the disruption of the cholinergic induction of receptivity by such lesions was due either to destruction of estrogen receptors located in cell bodies in the VMNH which send projections to extrahypothalamic cholinergic neurons or to estrogen- and cholinergic-responsive cells intrinsic to the VMNH which are critical for the expression of sexual receptivity.

The aberrant behavior checklist: factor structure and the effect of subject variables in American and New Zealand facilities

The Aberrant Behavior Checklist was used to collect data from a large United States institution for comparison with ratings previously obtained in New Zealand. A total of 531 subjects within the American facility and 937 residents of New Zealand institutions were studied. The United States data were factor analyzed using the same procedures that were employed to develop the scale in New Zealand. In addition, subscales of the Checklist were analyzed as a function of sex, age, country, and level of mental retardation. Finally, the effects of various medical conditions were analyzed. The original factor structure of the Checklist was validated for the United States sample, with a mean coefficient of congruence of .93 averaged across the five factors. Sex failed to influence subscale scores, whereas age, country, and severity of retardation significantly affected ratings. Deafness was unrelated to Checklist scores whereas cerebral palsy, epilepsy, psychosis, and psychoactive drug treatment were related.

Evidence for involvement of midbrain central gray in cholinergic mediation of female sexual receptivity in rats

Experiments were designed to determine the role of the midbrain central gray (MCG) in facilitation of lordosis by cholinergic agonists. In Experiment 1, estradiol-treated female rats received microinjections of carbachol into the MCG and showed a dose-related behavioral facilitation to the agonist. In Experiment 2, MCG injections of oxotremorine (OXO), a selective muscarinic receptor agonist, yielded a dose-related facilitation; this was blocked by systemic pretreatment with scopolamine (SCOP), a muscarinic antagonist. In Experiment 3, MCG-lesion animals were injected unilaterally with OXO intraventricularly following contralateral injection of SCOP or vehicle. Females with MCG damage displayed significantly less facilitation than sham-lesion animals. Pretreatment with SCOP abolished lordosis facilitation in both groups. In addition, after treatment with estradiol and progesterone, sham-lesion females showed more receptivity than MCG-lesion females. Systemic injection of SCOP produced a significant decline in lordosis for both groups. On the basis of these data, it is suggested that the MCG plays an important role in the cholinergic mediation of female sexual receptivity.

Cholinergic mediation of feminine sexual receptivity: demonstration of progesterone independence using a progestin receptor antagonist

Feminine sexual receptivity can be elicited by the intracerebral administration of muscarinic cholinergic substances in ovariectomized female rats treated with small amounts of estrogen. These experiments were designed to investigate whether this facilitative cholinergic mechanism is dependent upon progesterone. In the first experiment, estrogen-primed animals were injected with RU 38486, a progestin receptor antagonist, 1 h before progesterone or vehicle injection. Injection of RU and progesterone on Day 1 of testing produced animals which were sexually unreceptive. Furthermore, injection of the antagonist without concomitant progesterone produced animals which were unresponsive to progesterone given 24 h later. Thus, RU 38486 itself may be binding to progestin receptors in critical brain regions, preventing progesterone from binding to these same receptors. In Experiment 2, animals made sexually unreceptive by treatment with RU 38486 subsequently became receptive when injected intracerebrally with oxotremorine, a muscarinic agonist. Therefore, activation of progestin receptors does not appear necessary for the cholinergic mediation of sexual receptivity. As in Experiment 1, animals receiving progesterone on Day 1 showed a diminished response to a second progesterone injection 24 h later; an even greater decrease in this response was observed in animals that also received the antagonist on Day 1.

Evidence for involvement of midbrain central gray in cholinergic mediation of female sexual receptivity in rats

Experiments were designed to determine the role of the midbrain central gray (MCG) in facilitation of lordosis by cholinergic agonists. In Experiment 1, estradiol-treated female rats received microinjections of carbachol into the MCG and showed a dose-related behavioral facilitation to the agonist. In Experiment 2, MCG injections of oxotremorine (OXO), a selective muscarinic receptor agonist, yielded a dose-related facilitation; this was blocked by systemic pretreatment with scopolamine (SCOP), a muscarinic antagonist. In Experiment 3, MCG-lesion animals were injected unilaterally with OXO intraventricularly following contralateral injection of SCOP or vehicle. Females with MCG damage displayed significantly less facilitation than sham-lesion animals. Pretreatment with SCOP abolished lordosis facilitation in both groups. In addition, after treatment with estradiol and progesterone, sham-lesion females showed more receptivity than MCG-lesion females. Systemic injection of SCOP produced a significant decline in lordosis for both groups. On the basis of these data, it is suggested that the MCG plays an important role in the cholinergic mediation of female sexual receptivity.

Computers working for medicine

A demonstration of the use of Viewdata Systems in clinical trials is presented. The potential of these systems in several areas of medicine is shown and related to their speed of development in the last 2 years. Particular reference is made to the use of computers in the assessment of patients with affective disorders.

Further evidence for masculinization of female rats by males located caudally in utero

The morphology and behavior of female rodents is partially masculinized as a result of residence near males in the same uterine horn (Clemens effect). Two hypothetical mechanisms have been proposed to account for this effect. In the first hypothesis ("contiguity") androgens secreted by males in utero are proposed to diffuse across the amniotic membrane, reaching adjacent fetuses. In the second hypothesis ("caudal male") androgens are transported via the cervical-to-ovarian blood flow and may diffuse directly between closely apposed uterine veins and arteries. This study was designed to test directly which of these mechanisms appears more influential in masculinizing the morphology of female rats. Pregnant Sprague-Dawley rats were decapitated early on Day 22 of gestation and pups were Caesarean delivered. Their anogenital distance and body weight were recorded, location in utero coded by means of footpad tatooing, and each litter fostered to a maternal female. Measurements were taken again when the animals were weaned. Statistical analysis revealed that the presence of one or more males caudal to a female in the uterine horn has a more critical influence on that female's morphology than contiguity per se. Such a mechanism may result in partial masculinization of dimorphic behaviors later in life.

Improving profoundly mentally retarded adults' performance on a position discrimination

The relative importance of stimulus manipulations antecedent to or consequent on the response was investigated in three experiments related to position discrimination. In the first experiment, two different stimuli (either a piece of candy or a toy cat) were hidden under one of three boxes in full view of 2 profoundly mentally retarded adults. The behavior of uncovering the hidden object was measured using a combined multiple baseline and reversal design. In Experiment II, an entire unit of profoundly retarded adults was screened to determine the prevalence of the effects observed in Experiment I. In Experiment III, an attempt was made to determine whether the difference in antecedents (candy vs. kitty) or consequences accounted for the superior performance when the candy was hidden. In this experiment, using a reversal design with four profoundly retarded adults, we found that the antecedent manipulation (hiding the candy vs. hiding the toy cat) resulted in better performance than did the manipulation of the consequence (handing subjects the candy or allowing them to uncover and consume it).

Survey of bruxism in an institutionalized mentally retarded population

Bruxism was assessed in a population of 358 institutionalized mentally retarded individuals using two independent indexes: toothwear and staff reports. Bruxism based upon toothwear was found in 58%. Bruxism identified by staff reports was found in 41% of the population. No sex differences were observed. Three bruxer subgroups were identified: daytime only (17%), night only (8%), and day and night (16%). Older residents were more likely to grind their teeth than were younger residents. These results, when compared with other reports, suggest that bruxism is more likely to occur in the institutionalized mentally retarded population than in the nonretarded population.

Maternal discrimination of pup sex in rats

In recent studies (Moore, 1981, 1982; Moore & Morelli, 1979), it has been found that maternal female rats spend more time licking the anogenital region of male than female offspring. This discrimination of pup sex has important implications for the development of a number of sex differences in behavior later in life, and the present study was designed to re-examine Moore's observations while allowing each pup to be individually identified. Litters of Sprague-Dawley rats were delivered by Caesarean section, and the footpads of each animal were tattooed with India ink to permit identification throughout testing. Each litter was then fostered to a maternal female and remained with her except when observations of maternal licking were made--on the fourth, seventh, and tenth days after delivery. On each of these days, the foster mother was placed in a test chamber for 30 min, and each pup was then presented individually for a 10-min session. During this time the number and duration of anogenital licking episodes were recorded. We found, as did Moore, that adult females do distinguish between their male and female pups, spending significantly more time licking the anogenital region of the males in their litters on all but the first day of testing. The possibility that the attentional bias toward male young has important consequences for behavior later in life and contributes to behavioral differences between the sexes (Beach, 1979; Moore, 1982) makes the identification of individual animals throughout development important in the analysis of these effects.

Shaping bladder and bowel continence in developmentally retarded preschool children

A program to improve bladder and bowel continence was evaluated in a preschool with four developmentally retarded children. During baseline, the children were taken to the toilet on a regular schedule, once an hour. The training program increased this frequency to once every 15 minutes for the 1st week, every 30 minutes the 2nd week, every hour the 3rd week, and every 2 hours in the 4th week. Using the toilet appropriately was reinforced with social praise and liquids. Accidents resulted in a brief verbal reprimand and simple correction (i.e., going to the bathroom, changing clothes, and sitting on the toilet). All four children showed improvement in their bladder and bowel continence. Results of the program are discussed in terms of improved efficiency of toilet training programs and their use with developmentally retarded preschool children.

Evaluation of a treatment for a hand-mouthing stereotypy

A treatment procedure to reduce a hand-mouthing stereotypy was evaluated with three profoundly mentally retarded women. The procedure consisted of simple correction (a verbal reprimand and physically guiding the hands down) and differentially reinforcing the absence of hand-mouthing. The treatment procedure was initially effective for all three women and resulted in durable maintenance for two of them.