TGF-β in correlation with tumor progression, immunosuppression and targeted therapy in colorectal cancer

Colorectal cancer (CRC) is a complex malignancy responsible for the second-highest cancer deaths worldwide. TGF-β maintains normal cellular homeostasis by inhibiting the cell cycle and inducing apoptosis, but its elevated level is correlated with colorectal cancer progression, as TGF-β is a master regulator of the epithelial-to-mesenchymal transition, a critical step of metastasis. Tumors, including CRC, use elevated TGF-β levels to avoid immune surveillance by modulating immune cell differentiation, proliferation, and effector function. Presently, the treatment of advanced CRC is mainly based on chemotherapy, with multiple adverse effects. Thus, there is a need to develop alternate tactics because CRC continue to be mostly resistant to the present therapeutic regimen. TGF-β blockade has emerged as a promising therapeutic target in cancer therapy. Blocking TGF-β with phytochemicals and other molecules, such as antisense oligonucleotides, monoclonal antibodies, and bifunctional traps, alone or in combination, may be a safer and more effective way to treat CRC. Furthermore, combination immunotherapy comprising TGF-β blockers and immune checkpoint inhibitors is gaining popularity because both molecules work synergistically to suppress the immune system. Here, we summarize the current understanding of TGF-β as a therapeutic target for managing CRC and its context-dependent tumor-promoting or tumor-suppressing nature.

Identification of novel inhibitors from Urtica spp against TNBC targeting JAK2 receptor for breast cancer therapy

Breast cancer is the most prevalent form of cancer in women globally, and TNBC (triple-negative breast cancer) is its aggressive type since it lacks the usual targets. JAK2/STAT3 pathway can be an important lead in anticancer drug discovery, as restraining the downstream signalling of this pathway results in the induction of cell apoptosis. Moreover, various limitations associated with chemotherapy are the reason to find an alternative herbal-based therapy. For this study, we collected Urtica dioica and U. parviflora from different regions of Uttarakhand, followed by preparation of their leaf and stem extracts in different solvents. The GC-MS analysis of these extracts revealed a total of 175 compounds to be present in them. Further, by molecular docking approach, we studied the interaction between these compounds and JAK2, and 12 major compounds with better binding energy than the control Paclitaxel were identified. In addition, the selected hits were also reported to display better pharmacokinetic properties. Moreover, extracts from both the Urtica spp. displayed significant anticancer activity against MDA-MB-231(TNBC cell line) and exhibited lower cytotoxicity in healthy cell lines, i.e. HEK293T, indicating that these extracts were safer to use. Hence, the findings in our study can be crucial in the area of herbal-based target-specific drug development against breast cancer.

Plant-beneficial Bacillus, Pseudomonas, and Staphylococcus spp. from Kumaon Himalayas and their drought tolerance response

Plant growth-promoting rhizobacteria (PGPR) have been shown to augment plant responses against drought and other abiotic stresses. In the present study, we isolated 27 bacteria from the rhizosphere of various plants cultivated in the Kumaon Himalayas., and to measure their abiotic stress tolerance, these 27 isolates were subjected to variations in pH, temperature, and drought. All 27 isolates were also screened for various plant growth-promoting traits. Among these, the four isolates RR1, ASC1, AFS3, and NG4 demonstrated various plant growth promotion activities including the synthesis of indole-3-acetic acid (IAA), siderophores, ammonia, and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase production, and concomitantly high tolerance to abiotic stresses. Moreover, 16S rRNA sequencing of these four isolates validated their identities as Bacillus, Pseudomonas, and Staphylococcus sp. Finally, to assess the in-vivo drought tolerance potential of these four isolates, a pot-trial experiment was undertaken in wheat cultivar VL-892. The results demonstrated that inoculating wheat plants with these four PGPR isolates greatly improved plant growth under drought circumstances by increasing root and shoot length and both fresh and dry weight of root and shoot. This study endeavors to discover the biochemical and molecular diversity of cultivable PGPR in six remotely located districts of Uttarakhand. In conclusion, the drought-tolerant PGPR strains described in this study are plant-beneficial and can effectively mobilize nutrients under drought conditions. Consequently, they could be used as bioinoculants to alleviate drought stress in wheat plants, in a sustainable manner. To the best of our knowledge, this is the first report of exploring the diversity and characterization of PGPR from the Kumaon Himalayas and their drought evaluation.

Molecular docking and molecular dynamics simulation approaches for evaluation of laccase-mediated biodegradation of various industrial dyes

Dyes are being increasingly utilized across the globe, but there is no appropriate method of bioremediation for their full mineralization from the environment. Laccases are key enzymes that help microbes to degrade dyes as well as their intermediate metabolites. Various dyes have been reported to be degraded by bacteria, but it is still unclear how these enzymes function during dye degradation. To effectively eradicate toxic dyes from the system, it is essential to understand the molecular function of enzymes. As a result, the interaction of laccase with different toxic dyes was investigated using molecular docking. Based on the highest binding energy we have screened ten dyes with positive interaction with laccase. Evaluating the MD simulation results, three out of ten dyes were more stable as potential targets for degradation by laccase of Bacillus subtilis. As a result, subsequent research focused solely on the results of three substrates: pigment red, fuchsin base, and Sudan IV. Analysis of MD simulation revealed that pigments red 23, fuchsin base, and Sudan IV form hydrogen and hydrophobic bond as well as Vander Waals interactions with the active site of laccase to keep it stable in aqueous solution. The conformation of laccase is greatly altered by the inclusion of all three substrates in the active site. The MD simulation findings show that laccase complexes remain stable throughout the catalytic reaction. Therefore, this research provides a molecular understanding of laccase expression and its role in the bioremediation of the pigments red 23, fuchsin base, and Sudan IV.Communicated by Ramaswamy H. Sarma.

A Review on Immunological Responses to SARS-CoV-2 and Various COVID-19 Vaccine Regimens

The transmission of SARS-CoV-2 has caused serious health crises globally. So far, 7 vaccines that are already being assessed in Phase IV clinical trials are, Comirnaty/ Pfizer; Spikevax/Moderna (m RNA vaccine); Vaxzevria or Covishield; Ad26.COV2.S; Ad5-nCoV (adenoviral vector-based vaccine); CoronaVac and BBIBP-CorV (inactivated virus vaccine). Besides, there are about 280 vaccines that are undergoing preclinical and clinical trials including Sputnik-V, Covaxin or BBV152, and NVX-CoV2373. These vaccines are being studied for their immunological responses and efficiency against COVID-19, and have been reported to demonstrate effective T and B cell responses. However, the long-lasting immunity of these vaccine regimens still needs to be investigated. An in-depth understanding of the vaccine efficacy and immune control mechanism is imperative for the rational purposing and implementation of the vaccines. Hence, in this review, we have comprehensively discussed the immune response induced in COVID-19 patients, as well as in the convalescent individuals to avoid reinfection. Moreover, we have also summarized the immunological responses and prophylactic efficacy of various COVID-19 vaccine regimens. In this context, this review can give insights into the development of effective vaccines against SARS-CoV-2 and its variants in the future.

AB0358 SAFETY, TOLERABILITY, PHARMACOKINETICS, RECEPTOR OCCUPANCY, AND SUPPRESSION OF T-CELL-DEPENDENT ANTIBODY RESPONSE IN A PHASE 1 STUDY WITH KPL-404, AN ANTI-CD40 MONOCLONAL ANTIBODY

Background

T-cell priming and T-cell-dependent B-cell responses require an intact cluster of differentiation (CD)40/CD40L pathway. CD40 is expressed on the surface of B-cells, dendritic cells, antigen-presenting cells, and non-immune cell types; its ligand, CD40L (CD154), is expressed on the surface of activated T-cells, platelets, and other cell types. Blockade of CD40/CD40L interaction has been shown to ablate primary and secondary T-cell dependent antibody response (TDAR).

Objectives

We hypothesized that KPL-404, an anti-CD40 monoclonal antibody which inhibits interaction between CD40 and CD40L, would block T-cell dependent, B-cell-mediated autoimmunity in this Phase 1 study in healthy participants.

Methods

This randomized, double-blind, placebo-controlled, first-in-human study of KPL-404 in healthy participants was designed with two single-ascending-dose arms: single intravenous (IV) doses of 0.03 mg/kg, 0.3 mg/kg, 1 mg/kg, 3 mg/kg, or 10 mg/kg and single subcutaneous (SC) doses of 1 mg/kg or 5 mg/kg. The primary objective was safety and tolerability of KPL-404; secondary and exploratory objectives included pharmacokinetic (PK) parameters, TDAR inhibition, and receptor occupancy (RO). To evaluate TDAR inhibition, participants post-KPL-404 administration were immunized with 1 mg intramuscular injection of the test antigen Keyhole Limpet Hemocyanin (KLH) on day 4 and day 29 to elicit a primary and secondary Immunoglobulin (Ig) response, respectively. To evaluate RO, free and total CD40 receptor levels (percent change from baseline) on B-cells (whole blood) were measured using flow cytometry.

Results

There were no dose-limiting or dose-related safety findings in healthy participants after KPL-404 administration. One unrelated serious adverse event (patella fracture following a fall) occurred in the 10 mg/kg IV arm. The PK profile of KPL-404 in serum after IV or SC administration had low to moderate variability between individuals; elimination was dose-dependent and consistent with target-mediated drug disposition (TMDD) (Figure 1a). For participants receiving 10 mg/kg IV, full receptor occupancy was observed through day 71 (Figure 1b), complete TDAR suppression was observed through Day 57 (Figure 1c), and anti-drug antibodies to KPL-404 were suppressed for at least 57 days; the suppression of antibody responses to the drug itself is an independent indicator of target engagement and pharmacodynamic effect. For participants receiving 5 mg/kg SC, full receptor occupancy was observed through day 43 (Figure 1b), and complete TDAR suppression was observed through Day 29 (Figure 1c). The TDAR response to KLH antigen correlated with the observed full RO.

Conclusion

The safety and tolerability data and the PK/PD profile of KPL-404 support further investigation of KPL-404 in a broad range of autoimmune diseases, including rheumatoid arthritis. These data support the optionality for studying chronic KPL-404 dosing in patients with subcutaneous and/or intravenous administration.

Disclosure of Interests

Manoj Samant Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., Alistair Wheeler Consultant of: Kiniksa Pharmaceuticals Corp., Guang-Liang Jiang Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., Moses Njenga Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., Madeline Spiers Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., Arian Pano Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., John F. Paolini Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp.

AB0379 DOSE-DEPENDENT SUPPRESSION OF T CELL-DEPENDENT ANTIBODY RESPONSE IN HEALTHY VOLUNTEERS BY KPL-404, AN ANTI-CD40 MONOCLONAL ANTIBODY, SUPPORTS CHRONIC DOSING STUDY IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background

An unmet need remains in patients with failure and/or inadequate response (IR) to biological disease-modifying antirheumatic drugs (bDMARD-IR) and/or Janus kinase inhibitors (JAKi-IR). The CD40/CD40L (CD154) costimulatory pathway is linked to inflammation and joint destruction in RA via production of autoantibodies and inflammatory mediators. KPL-404 is a humanized IgG4 antibody engineered to bind CD40 without triggering Fc effector functions (Muralidharan, 2019), which are known to have been associated with thromboembolic events seen in the first generation of CD40L-targeting therapies.

In a first-in-human Phase 1 single ascending dose study, 52 healthy volunteers received single doses of KPL-404 administered either subcutaneously (SC) or intravenously (IV) with no dose-limiting safety findings, infectious episodes, or toxicities (Samant, 2021). The study demonstrated that with 10 mg/kg IV, full receptor occupancy (RO) was observed through day 71, and there was complete suppression of T-cell dependent antibody response (TDAR) to keyhole limpet hemocyanin challenge on day 1 and re-challenge on day 29 through day 57. With 5 mg/kg SC, full RO was observed through day 43, and there was complete suppression of TDAR through at least day 29. Complete suppression of ADA to KPL-404, an independent indicator of target engagement, was also observed while KPL-404 serum concentrations were above approximately 0.1 to 0.2 µg/mL and continued for at least 50 days and 57 days after 5 mg/kg SC and 10 mg/kg IV administration, respectively.

Objectives

Using Phase 1 and nonclinical data, identify chronic dosing regimens anticipated to yield PK in the sub-therapeutic, therapeutic, and supra-therapeutic ranges to be utilized in a Multiple Ascending Dose Phase 2 Study.

Methods

A PK model was used to simulate multiple dosing scenarios, including: 2.5, 5, and 10 mg/kg SC qwk, q2wk, and q4wk, as well as 10 mg/kg IV q4wk. The model was used to identify optimal Phase 2 dosing schedules by generating 1000 virtual subjects using the typical parameter estimates with between-subject variability included.

Results

Following SC administration, all subjects were predicted to achieve complete ADA suppression for the full dosing interval at/above 2.5 mg/kg SC q2wk. At 2 mg/kg SC q2wk (starting dose level), simulated steady-state 8-week data predicted PK in a sub-therapeutic range for most subjects and an approximately 31- and 18-fold safety margin relative to preclinical NOAEL dose. At 5 mg/kg SC q2wk, 100% of patients were predicted to be in a therapeutic range, indicating a potential practical efficacious dose level. At 10 mg/kg SC q2wk, 100% of patients were predicted to be in the supratherapeutic range.

These results support a Multiple Ascending Dose (MAD) Phase 2 study design, with PK lead-in comprised of 3 Cohorts at 2, 5, or 10 mg/kg SC q2wk (each randomized 6:2) and Proof-of-Concept phase (Cohort 4) comprised of 48-60 subjects randomized 1:1:1 to 10 mg/kg, 5 mg/kg, and placebo SC q2wk. The ongoing study will evaluate efficacy (Disease Activity of 28 joints using C-reactive protein [DAS28-CRP]), safety, PK, and pharmacodynamics (PD) of escalating doses levels of KPL-404 compared with placebo in patients with moderate to severe RA (bDMARD-IR or JAKi-IR). The study also allows the flexibility of optional cohorts including additional dosing regimens and/or subpopulations identified based on clinical response and biomarkers.

Conclusion

Inhibition of the CD40-CD154 co-stimulatory interaction holds promise for the management of a spectrum of autoimmune diseases. KPL-404 demonstrated prolonged absorption/excretion capable of suppressing TDAR for extended periods allowing for use of extended dosing intervals irrespective of IV or SC dosing. These analyses supported the design of the ongoing Phase 2 study assessing the efficacy and safety KPL-404 in RA.

References

[1]Muralidharan S et al. 2019. Poster at Keystone Symposia

[2]Samant M et al. Arthritis Rheumatol. 2021; 73(suppl 10)

Disclosure of Interests

Anastassia Papandrikopoulou Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., Gerd Rüdiger Burmester Speakers bureau: Abbvie, Amgen, BMS, Lilly, MSD, Pfizer, Roche, Sanofi, Consultant of: Abbvie, Amgen, BMS, Kiniksa, Lilly, MSD, Pfizer, Roche, Sanofi, Fang Fang Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., Alan Kivitz Shareholder of: Amgen, Gilead Sciences, Inc., GlaxoSmithKline, Novartis, Pfizer, Sanofi,, Speakers bureau: AbbVie, Celgene, Flexion, Genzyme, GlaxoSmithKline, Lilly, Merck, Novartis, Pfizer, Sanofi, UCB, Horizon, Consultant of: AbbVie, Boehringer Ingelheim, Flexion, Gilead Sciences, Inc., Janssen, Pfizer, Sanofi, SUN Pharma Advanced Research, Moses Njenga Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., Arian Pano Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., Costantino Pitzalis Speakers bureau: Abbott/AbbVie, Astra-

Zeneca/MedImmune, BMS, Janssen/J&J, MSD, Pfizer, Roche/Genentech/Chugai, UCB.,, Consultant of: Abbott/AbbVie, Astellas, Astra-Zeneca/MedImmune, BMS, CelGene, Grunenthal, GSK,

Janssen/J&J, Kiniksa, MSD, Pfizer, Sanofi, Roche / Genentech / Chugai, UCB., Grant/research support from: Abbott/AbbVie, Astellas, Astra-Zeneca/MedImmune, BMS, Janssen/J&J, MSD, Pfizer, Roche/Genentech/Chugai, UCB., Manoj Samant Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., Steve Schmitz Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., Madeline Spiers Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., Eben Tessari Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., John Ziemniak Consultant of: Kiniksa Pharmaceuticals, Ltd., John F. Paolini Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp.

Microbial Interventions in Bioremediation of Heavy Metal Contaminants in Agroecosystem

Soil naturally comprises heavy metals but due to the rapid industrialization and anthropogenic events such as uncontrolled use of agrochemicals their concentration is heightened up to a large extent across the world. Heavy metals are non-biodegradable and persistent in nature thereby disrupting the environment and causing huge health threats to humans. Exploiting microorganisms for the removal of heavy metal is a promising approach to combat these adverse consequences. The microbial remediation is very crucial to prevent the leaching of heavy metal or mobilization into the ecosystem, as well as to make heavy metal extraction simpler. In this scenario, technological breakthroughs in microbes-based heavy metals have pushed bioremediation as a promising alternative to standard approaches. So, to counteract the deleterious effects of these toxic metals, some microorganisms have evolved different mechanisms of detoxification. This review aims to scrutinize the routes that are responsible for the heavy metal(loid)s contamination of agricultural land, provides a vital assessment of microorganism bioremediation capability. We have summarized various processes of heavy metal bioremediation, such as biosorption, bioleaching, biomineralization, biotransformation, and intracellular accumulation, as well as the use of genetically modified microbes and immobilized microbial cells for heavy metal removal.

Identification of Putative Elicitors From Plant Root Exudates Responsible for PsoR Activation in Plant-Beneficial Pseudomonas spp. by Docking and Molecular Dynamics Simulation Approaches to Decipher Plant-Microbe Interaction

Plants and rhizobacteria are coexisting since the beginning, but the exact mechanism of communication between them remains enigmatic. The PsoR protein of plant-beneficial Pseudomonas spp., a group of root-associated bacteria, is known to produce a range of antifungal and insecticidal secondary metabolites like 2,4-diacetyl phloroglucinol (DAPG), pyrrolnitrin, and chitinase making them great biocontrol agents and thus helping in plant growth promotion. To better understand the inter-kingdom signaling between plants and plant growth-promoting rhizobacteria (PGPR), the interaction of PsoR with various root exudates was investigated computationally. For this, we first modeled the PsoR protein and confirmed it using the Ramachandran plot. A total of 59 different low molecular weight phytochemicals, secreted as root exudates by plants, were identified by extensive text mining. They were virtually screened with the PsoR protein by molecular docking. Based on the lowest binding energy, ranging from -7.1 to -6.3 kcal mol^-1, the top five exudates were chosen. To analyze the stability of the docked protein-ligand complex, a molecular dynamics (MD) simulation of 100 nanoseconds was done. Two root exudates, saponarin and 2-benzoxazolinone (BOA), showed suitable binding with PsoR by forming hydrogen, hydrophobic, and Van der Waals interactions. To confirm the MD simulation results, RMSF, RG, SASA, and interaction energy were calculated. This computational study first time reports that saponarin and 2-BOA, predominantly present in the root exudates of barley and wheat, respectively, demonstrate effective binding with the modeled PsoR protein and are likely of showing cross-kingdom interactions.

Interleukin-17-A multifaceted cytokine in viral infections

Viral infections are a major threat to the human population due to the lack of selective therapeutic measures. The morbidity and mortality reported worldwide are very alarming against viral pathogens. The proinflammatory environment is required for viral inhibition by initiating the host immune response. The host immune response fights these pathogens by secreting different cytokines. Interleukin-17 (IL-17) a proinflammatory cytokine mainly produced by T helper type 17 cells, plays a vital role in the regulation of host immune response against various pathogens, including viruses. However, dysregulated production of IL-17 induces chronic inflammation, autoimmune disorders, and may lead to cancer. Recent studies suggest that IL-17 is not only involved in the antiviral immune response but also promotes virus-mediated illnesses. In this review, we discuss the protective and pathogenic role of IL-17 against various viral infections. A detailed understanding of IL-17 during viral infections could contribute to improve therapeutic measures and enable the development of an efficient and safe IL-17 based immunotherapy.

Evaluation of the target-specific therapeutic potential of herbal compounds for the treatment of cancer

Cancer is among one of the most fatal diseases leading to millions of death around the globe. Chemotherapy is the most popular conventional approach for the treatment of cancer. However, this is usually associated with various side effects and puts the patients under extreme physical and mental stress. Besides, there are increasing concerns about drug resistance. Thus, to surmount these limitations, there is a need to explore some alternative treatments. Studies related to plant-derived compounds are crucial in the search for safer and more efficient treatments. Plants and their associated secondary metabolites have been a revolutionary approach in the field of cancer treatment, as they give answers to almost all the constraints faced by synthetic drugs. Various plants and associated secondary metabolites display a great prospective as cytotoxic anticancer agents due to their specific interference with validated drug targets, such as inhibitors of mitosis, topoisomerase I and II inhibitor, DNA interactive agent, protein kinase inhibitors, inhibitors of DNA synthesis. In this review, the therapeutic potential of various natural compounds and their derivatives are presented based on their molecular targets. These herbal compounds and their derivatives could provide a rich resource for novel anticancer drug development.

AB0370 UTILITY OF CRP AND ESR IN THE DIAGNOSIS OF GIANT CELL ARTERITIS RELAPSE IN A PHASE 2 TRIAL OF MAVRILIMUMAB

Background:

No universally accepted definition of flare currently exists in giant cell arteritis (GCA). Although relapses are defined mostly on clinical grounds (recurrence of GCA-related signs/symptoms), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) help clinicians assess disease activity. In fact, >70% of patients on glucocorticoids (GCs) alone have increased CRP or ESR when the disease is active. In contrast, tocilizumab, given its IL-6-blockade effect in the liver, rapidly reduces CRP and ESR levels, rendering them unreliable for disease activity monitoring. Mavrilimumab – a GM-CSF receptor α inhibitor with demonstrated efficacy in a Phase 2 GCA trial1 – downregulates inflammation upstream of IL-6. We hypothesized that mavrilimumab would not interfere with the utility of CRP and ESR in monitoring disease activity and in identifying GCA relapse.

Objectives:

To analyze the relationship between CRP/ESR and clinical disease activity in GCA patients treated with mavrilimumab.

Methods:

New-onset and relapsing GCA patients with active disease were recruited. GC-induced remission (no GCA symptoms and CRP <1 mg/dL or ESR <20 mm/hr) was required by baseline. Patients were randomized 3:2 to mavrilimumab 150 mg or placebo subcutaneously every 2 weeks plus a protocol-defined 26-week prednisone taper. The primary efficacy endpoint was time to relapse by Week 26. Relapse (adjudicated) was defined as recurrent GCA-related signs/symptoms, including new/worsening vasculitis on imaging, concurrent with CRP ≥1 mg/dL and/or ESR ≥30 mm/hr. CRP and ESR were also measured periodically during the trial.

This post hoc analysis assessed the association of recurrent GCA-related signs/symptoms with concurrent CRP or ESR elevation post-randomization by treatment arm. We also assessed the proportion of patients with CRP or ESR elevation without GCA-related signs/symptoms up to Week 26.

Results:

Seventy patients were enrolled (mavrilimumab, N=42; placebo, N=28). The association of CRP or ESR elevation with unequivocal GCA-related signs/symptoms post-randomization was consistent regardless of treatment arm: 8/8 in the mavrilimumab group and 13/13 in the placebo group (Table 1). During relapse, median (range) CRP was 1.8 (1.4 – 8.4) mg/dL (mavrilimumab group) and 1.8 (1.1 – 9.0) mg/dL (placebo group). Corresponding ESR values were 39.5 (30 – 102) mm/hr (mavrilimumab group) and 49 (31 – 101) mm/hr (placebo group). Four mavrilimumab recipients had self-limited, equivocal GCA-related signs/symptoms without concurrent CRP or ESR elevation; all 4 completed the prespecified GC taper by Week 26 without need for rescue GCs, so relapse was not confirmed. At least 1 elevated CRP or ESR value in the absence of GCA-related signs/symptoms was observed in 58.8% of mavrilimumab recipients and 93.3% of placebo recipients by Week 26.

Conclusion:

The observed association of CRP or ESR elevation with GCA-related signs/symptoms is consistent with the upstream mechanism and supports the utility of the stringent protocol definition of relapse. The frequency and magnitude of CRP and ESR elevations at relapse were similar in both treatment groups, suggesting that CRP and ESR remain useful in assessments of disease activity in mavrilimumab-treated patients. CRP and ESR elevations without GCA-related signs/symptoms occurred more often in placebo recipients.

References:

[1]Cid, Unizony et al. Arthritis Rheumatol. 2020; 72 (suppl 10)

Table 1.

CRP and ESR levels in patients with or without GCA relapse

Assessment§MavrilimumabPlaceboMavrilimumabPlaceboN=42N=28N=42N=28With RelapseWithout Relapse# of patients8 (19.1)13 (46.4)34 (81.0)15 (53.6) Elevated CRP* or ESR†8 (100.0)13 (100.0)20 (58.8)14 (93.3)  Elevated CRP*7 (87.5)10 (76.9)10 (29.4)11 (73.3)   Median (range) mg/dL1.8 (1.4 - 8.4)1.8 (1.1 - 9.0)2.6 (1.3 – 7.0)2.0 (1.0 – 6.6) Elevated ESR†6 (75.0)9 (69.2)16 (47.1)10 (66.7)  Median (range) mm/hr39.5 (30 - 102)49.0 (31 - 101)41.5 (30 - 110)53.5 (30 - 82)

§# (%), except where indicated otherwise.

*CRP ≥ 1 mg/dL

†ESR ≥ 30 mm/hr

Disclosure of Interests:

Sebastian Unizony Consultant of: Janssen and Kiniksa, Grant/research support from: Genentech, Maria C. Cid Speakers bureau: Roche and Kiniksa, Paid instructor for: GSK and Vifor, Consultant of: Janssen, GSK, and Abbvie, Grant/research support from: Kiniksa, Elisabeth Brouwer Speakers bureau: Dr. E.Brouwer as an employee of the UMCG received speaker fees and consulting fees from Roche in 2017 2018 which were paid to the UMCG., Consultant of: Dr. E.Brouwer as an employee of the UMCG received speaker fees and consulting fees from Roche in 2017 2018 which were paid to the UMCG., Lorenzo Dagna Speakers bureau: Abbvie, Amgen, Biogen, BMS, Celltrion, Galapagos, Glaxo SmithKline, Novartis, Pfizer, Roche, Sanofi-Genzyme, SOBI, Consultant of: Abbvie, Amgen, Biogen, BMS, Celltrion, Galapagos, Glaxo SmithKline, Novartis, Pfizer, Roche, Sanofi-Genzyme, SOBI; clinical trial for Kiniksa, Grant/research support from: Abbvie, Amgen, BMS, Celltrion, Galapagos, Novartis, Pfizer, Roche, Sanofi-Genzyme, SOBI, Merk Sharp &Dohme, Janssen, Kiniksa, Bhaskar Dasgupta Paid instructor for: Educational grant symposium/workshop for Roche-chugai, Sanofi, and Abbvie, Consultant of: CI UK for the Kiniksa trial, Grant/research support from: Educational grant symposium/workshop for Roche-chugai, Sanofi, and Abbvie, Bernhard Hellmich Consultant of: Honoraria paid to the institution for participation in the clinical trial, Eamonn Molloy: None declared, Carlo Salvarani: None declared, Bruce C. Trapnell Consultant of: Consultant member of DSMB for Kiniksa., Kenneth J Warrington Consultant of: Clinical trial support from Eli Lilly and Kiniksa, Ian Wicks: None declared, Manoj Samant Shareholder of: Kiniksa Pharmaceuticals, Employee of: Kiniksa Pharmaceuticals, Teresa Zhou Shareholder of: Kiniksa Pharmaceuticals, Employee of: Kiniksa Pharmaceuticals, Lara Pupim Shareholder of: Kiniksa Pharmaceuticals, Employee of: Kiniksa Pharmaceuticals, John F. Paolini Shareholder of: Kiniksa Pharmaceuticals, Employee of: Kiniksa Pharmaceuticals

LB0001 MAVRILIMUMAB IMPROVES OUTCOMES IN PHASE 2 TRIAL IN NON-MECHANICALLY-VENTILATED PATIENTS WITH SEVERE COVID-19 PNEUMONIA AND SYSTEMIC HYPERINFLAMMATION

Background:

Granulocyte/macrophage-colony stimulating factor (GM-CSF) is a cytokine both vital to lung homeostasis and important in regulating inflammation and autoimmunity1,2,3 that has been implicated in the pathogenesis of respiratory failure and death in patients with severe COVID-19 pneumonia and systemic hyperinflammation.4-6 Mavrilimumab is a human anti GM-CSF receptor α monoclonal antibody capable of blocking GM-CSF signaling and downregulating the inflammatory process.

Objectives:

To evaluate the effect of mavrilimumab on clinical outcomes in patients hospitalized with severe COVID-19 pneumonia and systemic hyperinflammation.

Methods:

This on-going, global, randomized, double-blind, placebo-controlled seamless transition Phase 2/3 trial was designed to evaluate the efficacy and safety of mavrilimumab in adults hospitalized with severe COVID-19 pneumonia and hyperinflammation. The Phase 2 portion comprised two groups: Cohort 1 patients requiring supplemental oxygen therapy without mechanical ventilation (to maintain SpO2 ≥92%) and Cohort 2 patients requiring mechanical ventilation, initiated ≤48 hours before randomization. Here, we report results for Phase 2, Cohort 1: 116 patients with severe COVID- 19 pneumonia and hyperinflammation from USA, Brazil, Chile, Peru, and South Africa; randomized 1:1:1 to receive a single intravenous administration of mavrilimumab (10 or 6 mg/kg) or placebo. The primary efficacy endpoint was proportion of patients alive and free of mechanical ventilation at Day 29. Secondary endpoints included [1] time to 2-point clinical improvement (National Institute of Allergy and Infectious Diseases COVID-19 ordinal scale), [2] time to return to room air, and [3] mortality, all measured through Day 29. The prespecified evidentiary standard was a 2-sided α of 0.2 (not adjusted for multiplicity).

Results:

Baseline demographics were balanced among the intervention groups; patients were racially diverse (43% non-white), had a mean age of 57 years, and 49% were obese (BMI ≥ 30). All patients received the local standard of care: 96% received corticosteroids (including dexamethasone) and 29% received remdesivir. No differences in outcomes were observed between the 10 mg/kg and 6 mg/kg mavrilimumab arms. Results for these groups are presented together. Mavrilimumab recipients had a reduced requirement for mechanical ventilation and improved survival: at day 29, the proportion of patients alive and free of mechanical ventilation was 12.3 percentage points higher with mavrilimumab (86.7% of patients) than placebo (74.4% of patients) (Primary endpoint; p=0.1224). Mavrilimumab recipients experienced a 65% reduction in the risk of mechanical ventilation or death through Day 29 (Hazard Ratio (HR) = 0.35; p=0.0175). Day 29 mortality was 12.5 percentage points lower in mavrilimumab recipients (8%) compared to placebo (20.5%) (p=0.0718). Mavrilimumab recipients had a 61% reduction in the risk of death through Day 29 (HR= 0.39; p=0.0726). Adverse events occurred less frequently in mavrilimumab recipients compared to placebo, including secondary infections and thrombotic events (known complications of COVID-19). Thrombotic events occurred only in the placebo arm (5/40 [12.5%]).

Conclusion:

In a global, diverse population of patients with severe COVID-19 pneumonia and hyperinflammation receiving supplemental oxygen therapy, corticosteroids, and remdesivir, a single infusion of mavrilimumab reduced progression to mechanical ventilation and improved survival. Results indicate mavrilimumab, a potent inhibitor of GM-CSF signaling, may have added clinical benefit on top of the current standard therapy for COVID-19. Of potential importance is that this treatment strategy is mechanistically independent of the specific virus or viral variant.

References:

[1]Trapnell, Nat Rev Dis Pri, 2019

[2]Wicks, Nat Rev Immunology, 2015

[3]Hamilton, Exp Rev Clin Immunol, 2015

[4]De Luca, Lancet Rheumatol, 2020

[5]Cremer, Lancet Rheumatol, 2021

[6]Zhou, Nature, 2020

Disclosure of Interests:

Lara Pupim Employee of: Kiniksa, Shareholder of: Kiniksa, Tisha S. Wang Consultant of: Partner Therapeutics; steering committee for Kinevant BREATHE clinical trial, Kristin Hudock: None declared, Joshua Denson: None declared, Nyda Fourie: None declared, Luis Hercilla Vasquez: None declared, Kleber Luz: None declared, Mohammad Madjid Grant/research support from: Kiniksa, Kirsten McHarry: None declared, José Francisco Saraiva: None declared, Eduardo Tobar: None declared, Teresa Zhou Employee of: Kiniksa, Shareholder of: Kiniksa, Manoj Samant Employee of: Kiniksa, Shareholder of: Kiniksa, Joseph Pirrello Employee of: Kiniksa, Shareholder of: Kiniksa, Fang Fang Employee of: Kiniksa, Shareholder of: Kiniksa, John F. Paolini Employee of: Kiniksa, Shareholder of: Kiniksa, Arian Pano Employee of: Kiniksa, Shareholder of: Kiniksa, Bruce C. Trapnell: None declared

OP0059 MAVRILIMUMAB (ANTI GM-CSF RECEPTOR Α MONOCLONAL ANTIBODY) REDUCES RISK OF FLARE AND INCREASES SUSTAINED REMISSION IN A PHASE 2 TRIAL OF PATIENTS WITH GIANT CELL ARTERITIS

Background:

T helper (Th)1 and Th17 lymphocytes play a role in the pathogenesis of giant cell arteritis (GCA). Current treatments primarily target the Th17 axis, possibly leaving residual Th1 activity. Granulocyte macrophage colony stimulating factor (GM-CSF), a mediator of Th1 and Th17 cells, is a pathogenic factor in GCA.

Objectives:

To evaluate the efficacy and safety of the GM-CSF inhibitor mavrilimumab in patients with GCA.

Methods:

Randomized, double-blind, placebo-controlled phase 2 trial enrolling patients with active, biopsy- or imaging-proven new onset (N/O) or relapsing refractory (R/R) GCA. Active disease: GCA symptoms and erythrocyte sedimentation rate (ESR) (>30 mm/hr) and/or C-reactive protein (CRP) (≥1 mg/dL) elevation within 6 weeks from randomization. Corticosteroid-induced remission (resolution of GCA symptoms and CRP <1 mg/dL or ESR <20 mm/hr) was required by baseline. 3:2 randomization to mavrilimumab 150 mg or placebo subcutaneously every 2 weeks and protocol-defined 26-week prednisone taper starting at 20-60 mg/day.

Primary efficacy endpoint: time to first adjudicated flare (ESR ≥30 mm/hr and/or CRP ≥1 mg/dL and GCA symptoms or new/worsening vasculitis on imaging) by Week 26 in all treated patients. Key secondary endpoint: sustained remission through Week 26. Safety up to Week 38 was assessed.

Results:

70 patients (35 N/O, 35 R/R) were enrolled (mavrilimumab [N=42] or placebo [N=28]). Mean (SD) age was 69.7 (7.48) years and 71.4% were female. Flare by Week 26 occurred in 8 (19%) and 13 (46.4%) patients receiving mavrilimumab and placebo, respectively (27.4 percentage points reduction). Median time to flare by Week 26 could not be estimated in the mavrilimumab group due to too few events (Not Estimable) and was 25.1 weeks [95% CI: (16.0, NE)] in the placebo group (HR [95% CI] 0.38 [0.15, 0.92]; p=0.0263) (Figure). Sustained remission at Week 26 occurred in 83.2% of patients receiving mavrilimumab and 49.9% of those receiving placebo (33.4 percentage points increase; p=0.0038). Results were consistent across disease type subgroups (HR for flare: N/O 0.29 [95% CI: 0.06, 1.31; nominal p= 0.0873]; R/R 0.43 [95% CI: 0.14, 1.30]; nominal p=0.1231), although not powered for significance (Table). Adverse events (AEs), mostly mild to moderate, were comparable between groups. There were 5 serious AEs (mavrilimumab 2 [4.8%], placebo 3 [10.7%]), none drug-related. No deaths or vision loss occurred. No adjudicated cases of pulmonary alveolar proteinosis were observed.

Table 1.

Efficacy at Week 26

All Patients [1]SubgroupsN/OR/RMavrilimu-mab (N=42)Placebo (N=28)Mavrilimu-mab (N=24)Placebo (N=11)Mavrilimu-mab (N=18)Placebo (N=17)Patients with Flare, n (%)8 (19.0)13 (46.4)3 (12.5)4 (36.4)5 (27.8)9 (52.9)Time to Flare (weeks) [2]Median, 95% CINE (NE, NE)25.1 (16.0, NE)NE (NE, NE)NE (11.7, NE)NE (16.4, NE)22.6 (16.0, NE)HR (Mavrilimumab vs Placebo), 95% CI [3]0.38 (0.15, 0.92)0.29 (0.06, 1.31)0.43 (0.14, 1.30)P-value [4] [5]0.02630.08730.1231Sustained Remission (%), 95% CI [6]83.2 (67.9, 91.6)49.9 (29.6, 67.3)91.3 (69.3, 97.7)62.3 (27.7, 84.0)72.2 (45.6, 87.4)41.7 (17.4, 64.5)Difference in Proportions (95% CI) [7]33.3 (10.7, 55.8)28.9 (-2.7, 60.5)30.6 (-2.1, 63.2)P-value [5] [7]0.00380.07270.0668

NE = Not estimable. [1] Total mITT population. Stratified by randomization strata. [2] Kaplan-Meier. [3] Cox proportional-hazards model; treatment as covariate. [4] Log-rank test. [5] N/O and R/R subgroups not powered for significance; nominal p values reported. [6] Kaplan-Meier Survival Estimates with standard error. [7] Two-sided p-value for the difference in sustained remission between 2 arms using normal approximation. Placebo arm is reference.

Conclusion:

Mavrilimumab was superior to placebo on the primary and secondary efficacy endpoints of time to flare and sustained remission at week 26 in patients with GCA. Mavrilimumab was well tolerated, and no new safety signals were observed.

Disclosure of Interests:

Maria C. Cid Speakers bureau: meeting attendance support from Roche and Kiniksa, Paid instructor for: educational from GSK and Vifor, Consultant of: consulting for Janssen, GSK, and Abbvie, Grant/research support from: research grant from Kiniksa, Sebastian Unizony Consultant of: consulting for Janssen and Kiniksa, Grant/research support from: research support from Genentech, Lara Pupim Shareholder of: Kiniksa Pharmaceuticals, Employee of: Kiniksa Pharmaceuticals, Fang Fang Shareholder of: Kiniksa Pharmaceuticals, Employee of: Kiniksa Pharmaceuticals, Joseph Pirrello Shareholder of: Kiniksa Pharmaceuticals, Employee of: Kiniksa Pharmaceuticals, Ai Ren Shareholder of: Kiniksa Pharmaceuticals, Employee of: Kiniksa Pharmaceuticals, Manoj Samant Shareholder of: Kiniksa Pharmaceuticals, Employee of: Kiniksa Pharmaceuticals, Teresa Zhou Shareholder of: Kiniksa Pharmaceuticals, Employee of: Kiniksa Pharmaceuticals, John F. Paolini Shareholder of: Kiniksa Pharmaceuticals, Employee of: Kiniksa Pharmaceuticals

Role of Cytokines in Experimental and Human Visceral Leishmaniasis

Visceral Leishmaniasis (VL) is the most fatal form of disease leishmaniasis. To date, there are no effective prophylactic measures and therapeutics available against VL. Recently, new immunotherapy-based approaches have been established for the management of VL. Cytokines, which are predominantly produced by helper T cells (Th) and macrophages, have received great attention that could be an effective immunotherapeutic approach for the treatment of human VL. Cytokines play a key role in forming the host immune response and in managing the formation of protective and non-protective immunities during infection. Furthermore, immune response mediated through different cytokines varies from different host or animal models. Various cytokines viz. IFN-γ, IL-2, IL-12, and TNF-α play an important role during protection, while some other cytokines viz. IL-10, IL-6, IL-17, TGF-β, and others are associated with disease progression. Therefore, comprehensive knowledge of cytokine response and their interaction with various immune cells is very crucial to determine appropriate immunotherapies for VL. Here, we have discussed the role of cytokines involved in VL disease progression or host protection in different animal models and humans that will determine the clinical outcome of VL and open the path for the development of rapid and accurate diagnostic tools as well as therapeutic interventions against VL.

DDX3 DEAD-box RNA helicase (Hel67) gene disruption impairs infectivity of Leishmania donovani and induces protective immunity against visceral leishmaniasis

Visceral leishmaniasis (VL) is a vector-borne disease caused by the digenetic protozoan parasite Leishmania donovani complex. So far there is no effective vaccine available against VL. The DDX3 DEAD-box RNA Helicase (Hel67) is 67 kDa protein which is quite essential for RNA metabolism, amastigote differentiation, and infectivity in L. major and L. infantum. To investigate the role of Hel67 in the L. donovani, we created L. donovani deficient in the Hel67. Helicase67 null mutants (LdHel67^-/-) were not able to differentiate as axenic amastigotes and were unable to infect the hamster. So, we have analyzed the prophylactic efficacy of the LdHel67^-/- null mutant in hamsters. The LdHel67^-/- null mutant based candidate vaccine exhibited immunogenic response and a higher degree of protection against L. donovani in comparison to the infected control group. Further, the candidate vaccine displayed antigen-specific delayed-type hypersensitivity (DTH) as well as strong antibody response and NO production which strongly correlates to long term protection of candidate vaccine against the infection. This study confirms the potential of LdHel67^-/- null mutant as a safe and protective live attenuated vaccine candidate against visceral leishmaniasis.

Current approaches for target-specific drug discovery using natural compounds against SARS-CoV-2 infection

•

The pandemic of COVID-19 remains to affect the whole world.

•

Current remedies for COVID-19 is not satisfactory/available.

•

The therapeutic efficacy of Natural Compounds is well explored in various viral infections.

•

Natural Compounds could be explored as target specific therapeutic agents against COVID-19 infection.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) recently caused a pandemic outbreak called coronavirus disease 2019 (COVID-19). This disease has initially been reported in China and also now it is expeditiously spreading around the globe directly among individuals through coughing and sneezing. Since it is a newly emerging viral disease and obviously there is a lack of anti-SARS-CoV-2 therapeutic agents, it is urgently required to develop an effective anti-SARS-CoV-2-agent.Through recent advancements in computational biology and biological assays, several natural compounds and their derivatives have been reported to confirm their target specific antiviral potential against Middle East respiratory syndrome coronavirus (MERS-CoV) or Severe Acute Respiratory Syndrome(SARS-CoV).These targets including an important host cell receptor, i.e., angiotensin-converting enzyme ACE2 and several viral proteins e.g. spike glycoprotein (S) containing S1 and S2 domains, SARS CoV Chymotrypsin-like cysteine protease (3CL^pro), papain-like cysteine protease (PL^pro), helicases and RNA-dependent RNA polymerase (RdRp). Due to physical, chemical, and some genetic similarities of SARS CoV-2 with SARS−COV and MERS−COV, repurposing various anti-SARS−COV or anti-MERS−COV natural therapeutic agents could be helpful for the development of anti−COVID-19 herbal medicine. Here we have summarized various drug targets in SARS−COV and MERS−COV using several natural products and their derivatives, which could guide researchers to design and develop a safe and cost-effective anti-SARS−COV-2 drugs.

Vaccination strategies to combat novel corona virus SARS-CoV-2

The 2019-novel coronavirus disease (COVID-19) is caused by SARS-CoV-2 is transmitted from human to human has recently reported in China. Now COVID-19 has been spread all over the world and declared epidemics by WHO. It has caused a Public Health Emergency of International Concern. The elderly and people with underlying diseases are susceptible to infection and prone to serious outcomes, which may be associated with acute respiratory distress syndrome (ARDS) and cytokine storm. Due to the rapid increase of SARS-CoV-2 infections and unavailability of antiviral therapeutic agents, developing an effective SAR-CoV-2 vaccine is urgently required. SARS-CoV-2 which is genetically similar to SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV) is an enveloped, single and positive-stranded RNA virus with a genome comprising 29,891 nucleotides, which encode the 12 putative open reading frames responsible for the synthesis of viral structural and nonstructural proteins which are very similar to SARS-CoV and MERS-CoV proteins. In this review we have summarized various vaccine candidates i.e., nucleotide, subunit and vector based as well as attenuated and inactivated forms, which have already been demonstrated their prophylactic efficacy against MERS-CoV and SARS-CoV, so these candidates could be used as a potential tool for the development of a safe and effective vaccine against SARS-CoV-2.

DNA-based microarray studies in visceral leishmaniasis: identification of biomarkers for diagnostic, prognostic and drug target for treatment

Visceral leishmaniasis (VL) is one of the major infectious diseases affecting the poorest regions of the world. Current therapy is not very much satisfactory. The alarming rise of drug resistance and the unavailability of an effective vaccine against VL urges research towards identifying new targets or biomarkers for its effective treatment. New technology developments offer some fresh hope in its diagnosis, treatment, and control. DNA microarray approach is now broadly used in parasitology research to facilitate the thoughtful of mechanisms of disease and identification of drug targets and biomarkers for diagnostic and therapeutic development. An electronic search on "VL" and "Microarray" was conducted in Medline and Scopus and papers published in the English mentioning use of DNA microarray on VL were selected and read to write this paper review. Functional analysis and interpretation of microarray results remain very challenging due to the inherent nature of experimental workflows, access, cost, and complexity of data obtained. We have explained and emphasized the use of curate knowledge of microarray in the case of VL for the identification of therapeutic target and biomarker and their selection/implementation in clinical use.

Genetically modified live attenuated vaccine: A potential strategy to combat visceral leishmaniasis

Visceral leishmaniasis (VL) is caused by a protozoan parasite Leishmania donovani mainly influencing the population of tropical and subtropical regions across the globe. The arsenal of drugs available is limited, and prolonged use of such drugs makes parasite to become resistant. Therefore, it is very imperative to develop a safe, cost-effective and inexpensive vaccine against VL. Although in recent years, many strategies have been pursued by researchers, so far only some of the vaccine candidates reached for clinical trial and more than half of them are still in pipeline. There is now a broad consent among Leishmania researchers that the perseverance of parasite is very essential for eliciting a protective immune response and may perhaps be attained by live attenuated parasite vaccination. For making a live attenuated parasite, it is very essential to ensure that the parasite is deficient of virulence and should further study genetically modified parasites to perceive the mechanism of pathogenesis. So it is believed that in the near future, a complete understanding of the Leishmania genome will explore clear strategies to discover a novel vaccine. This review describes the need for a genetically modified live attenuated vaccine against VL, and obstacles associated with its development.

A spotlight on the diagnostic methods of a fatal disease Visceral Leishmaniasis

Leishmania donovani (a causative agent of visceral leishmaniasis) poses a serious health threat to the human population which is fatal if left untreated. The life cycle of Leishmania alternates between vertebrate host and Phlebotomine fly as intermediate ones. Due to the difficulties linked to vector (sandfly) control and the lack of an effective vaccine, the control of leishmaniasis relies mostly on chemotherapy. Unfortunately, the prevalence of parasites becoming resistant to the first-line drug pentavalent antimonial (Sb^V )/sodium antimony gluconate (SAG) and some other anti-leishmanial drug is increasing in several parts of the world. With the alarming rise of drug resistance and other issues related to VL, there is an urgent need to focus on early detection and quick diagnosis of VL case. Therefore, we have reviewed most of the methods used in the diagnostic process of VL. Along with existing diagnostic methods, developing more effective and sensitive diagnostic methods and biomarkers is also vital for enhancing VL identification and control programs. This review gathers the comprehensive information on diagnostics methods of VL under a single umbrella that could be the prominent tools for the development of rapid, accurate and cost-effective diagnostic kits for VL which can be used in field conditions.

Identification of trans-2-cis-8-Matricaria-ester from the Essential Oil of Erigeron multiradiatus and Evaluation of Its Antileishmanial Potential by in Vitro and in Silico Approaches

The essential oil (EO) composition of the aerial parts of Erigeron multiradiatus (Lindl.ex DC.) Benth growing wild in the central Himalayan region of Uttarakhand, India, was analyzed by capillary gas chromatography with a flame ionization detector and gas chromatography-mass spectrometry. A sum of 12 constituents was identified, representing 97.81% of the oil composition. The oil was composed mainly of oxygenated monoterpenes (88.95%), sesquiterpene hydrocarbons (5.61%), oxygenated sesquiterpenes (3.05%), and monoterpene hydrocarbons (0.20%). Major constituents identified were trans-2-cis-8-matricaria-ester (77.79%), cis-lachnophyllum ester (11.04%), zingiberene (4.43%), and spathulenol (1.59%). Further, the leishmanicidal effect of EO and the purified compound trans-2-cis-8-matricaria-ester has been investigated against Leishmania donovani promastigotes and intracellular amastigotes. EO and trans-2-cis-8-matricaria-ester were safer for the hamster peritoneal macrophage and lethal to promastigotes and intracellular amastigotes at different concentrations. Further, using an in silico approach, these four compounds were tested against 10 major proteins of L. donovani associated with its virulence. Out of them, only trans-2-cis-8-matricaria-ester was found to be effective against the four target proteins, namely, l-asparaginase-1-like protein, metacaspase 2, metacaspase 1, and DNA topoisomerase II of L. donovani. The results indicate that EO contains trans-2-cis-8-matricaria-ester as a major component and showed antileishmanial activity which may facilitate discovery of new lead molecules for developing herbal medicines against visceral leishmaniasis.

Immunostimulatory potential and proteome profiling of Leishmania donovani soluble exogenous antigens

Isolation of the soluble exogenous antigens (SEAgs), its immune response study and proteome profiling is an essential prerequisite for understanding the molecular pathogenesis of Leishmania donovani. The immunostimulatory potential of L. donovani SEAgs, purified from culture of L. donovani clinical isolate, was evaluated for their ability to induce cellular responses in treated/cured hamsters. SEAgs induced significant proliferative responses in lymphocytes (SI 5.6 ± 2.3; P < 0.01) isolated from cured hamster. In addition, significant NO production in response to SEAgs was also noticed in macrophages of hamsters, mouse and human cell lines (J774A-1 and THP1). Western blot analyses with antibodies against proteophosphoglycan (PPG; surface-expressed and secreted molecule) of L. donovani revealed that PPG molecules are also present in L. donovani SEAgs. Mass spectrometry (MS)-based proteome analysis of 12 protein bands of SEAgs through MALDI-TOF/TOF endorsed the identification of some Th1-stimulatory immunogenic proteins. These immunogenic proteins may offer increased hope for the discovery of new promising vaccine candidates against visceral leishmaniasis (VL). The overall results suggest that immunostimulatory molecules are present in the SEAgs, which may be further exploited, for developing a subunit vaccine against VL a fatal human disease.

Trastuzumab emtansine (T-DM1) versus lapatinib plus capecitabine in patients with HER2-positive metastatic breast cancer and central nervous system metastases: a retrospective, exploratory analysis in EMILIA

BACKGROUND

We characterized the incidence of central nervous system (CNS) metastases after treatment with trastuzumab emtansine (T-DM1) versus capecitabine-lapatinib (XL), and treatment efficacy among patients with pre-existing CNS metastases in the phase III EMILIA study.

PATIENTS AND METHODS

In EMILIA, patients with human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer previously treated with trastuzumab and a taxane were randomized to T-DM1 or XL until disease progression. Patients with treated, asymptomatic CNS metastases at baseline and patients developing postbaseline CNS metastases were identified retrospectively by independent review; exploratory analyses were carried out.

RESULTS

Among 991 randomized patients (T-DM1 = 495; XL = 496), 95 (T-DM1 = 45; XL = 50) had CNS metastases at baseline. CNS progression occurred in 9 of 450 (2.0%) and 3 of 446 (0.7%) patients without CNS metastases at baseline in the T-DM1 and XL arms, respectively, and in 10 of 45 (22.2%) and 8 of 50 (16.0%) patients with CNS metastases at baseline. Among patients with CNS metastases at baseline, a significant improvement in overall survival (OS) was observed in the T-DM1 arm compared with the XL arm [hazard ratio (HR) = 0.38; P = 0.008; median, 26.8 versus 12.9 months]. Progression-free survival by independent review was similar in the two treatment arms (HR = 1.00; P = 1.000; median, 5.9 versus 5.7 months). Multivariate analyses demonstrated similar results. Grade ≥3 adverse events were reported in 48.8% and 63.3% of patients with CNS metastases at baseline administered T-DM1 and XL, respectively; no new safety signals were observed.

CONCLUSION

In this retrospective, exploratory analysis, the rate of CNS progression in patients with HER2-positive advanced breast cancer was similar for T-DM1 and for XL, and higher overall in patients with CNS metastases at baseline compared with those without CNS metastases at baseline. In patients with treated, asymptomatic CNS metastases at baseline, T-DM1 was associated with significantly improved OS compared with XL.

Synergistic metabolic benefits of an exenatide analogue and cholecystokinin in diet-induced obese and leptin-deficient rodents

AIM

To test the impact of cholecystokinin (CCK) plus either amylin or a glucagon-like peptide-1 receptor (GLP-1R) agonist on metabolic variables in diet-induced obese (DIO) rodents.

METHODS

A stabilized acetylated version of CCK-8 (Ac-Y*-CCK-8), selective CCK1 receptor (CCK1R) or CCK2 receptor (CCK2R) agonists, amylin or the GLP-1R agonist and exenatide analogue AC3174 were administered in select combinations via continuous subcutaneous infusion to DIO rats for 14 days, or Lep(ob) /Lep(ob) mice for 28 days, and metabolic variables were assessed.

RESULTS

Combined administration of Ac-Y*-CCK-8 with either amylin or AC3174 induced greater than additive weight loss in DIO rats, with the overall magnitude of effect being greater with AC3174 + Ac-Y*-CCK-8 treatment. Co-infusion of AC3174 with a specific CCK1R agonist, but not a CCK2R agonist, recapitulated the weight loss mediated by AC3174 + Ac-Y*-CCK-8 in DIO rats, suggesting that synergy is mediated by CCK1R activation. In a 4 × 4 full-factorial response surface methodology study in DIO rats, a synergistic interaction between AC3174 and the CCK1R-selective agonist on body weight and food intake was noted. Co-administration of AC3174 and the CCK1R-selective agonist to obese diabetic Lep(ob) /Lep(ob) mice elicited a significantly greater reduction in percentage of glycated haemoglobin and food intake relative to the sum effects of monotherapy groups.

CONCLUSIONS

The anti-obesity and antidiabetic potential of combined GLP-1R and CCK1R agonism is an approach that warrants further investigation.

Abstract P4-12-27: Efficacy and safety of trastuzumab emtansine (T-DM1) vs lapatinib plus capecitabine (XL) in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) and central nervous system (CNS) metastases: Results from a retrospective exploratory analysis of EMILIA

Introduction

T-DM1 is an antibody–drug conjugate that was recently approved by the FDA for patients with HER2-positive MBC who have received prior treatment with trastuzumab and a taxane. In the phase 3 EMILIA trial, T-DM1 significantly prolonged progression-free survival (PFS) and overall survival (OS) compared with XL in patients with previously treated HER2-positive MBC (Verma 2012). Because the CNS is a common site of progression in HER2-positive MBC, it is of interest to characterize the incidence of CNS metastases in patients treated with TDM1 vs XL and the efficacy of T-DM1 in patients with pre-existing CNS metastases.

Methods

EMILIA is a multicenter, randomized, open-label trial in which patients with HER2-positive, unresectable, locally advanced or MBC previously treated with trastuzumab and a taxane were randomized (1:1) to T-DM1 (3.6 mg/kg every 21 days) or XL (X: 1000 mg/m2 bid on days 1–14 of each 21-day cycle; L: 1250 mg/day on days 1–21). Treatment continued until disease progression or unacceptable toxicity. All patients underwent brain magnetic resonance imaging or computed tomography at screening, and follow-up scans were performed as clinically indicated. Those with untreated or symptomatic brain metastases and those who required therapy for symptom control ≤2 months before randomization were excluded from the trial. Patients with CNS metastases at baseline or who developed CNS metastases on study were retrospectively identified using independent review committee data, and exploratory analyses were performed on data from these patients.

Results

Of the 896 patients without CNS metastases at baseline (T-DM1 = 450; XL = 446), 9 (1.8%) and 3 (0.6%), respectively, developed CNS progression on study. Of the 95 patients with CNS metastases at baseline (T-DM1 = 45; XL = 50), 10 (2.0%) and 8 (1.6%), respectively, developed CNS progression on study. Median PFS in patients with CNS metastases at baseline was 5.9 months in the T-DM1 arm and 5.7 months in the XL arm (HR = 1.000; 95% CI: 0.542–1.844; P = 0.9998). Median OS was 26.8 months and 12.9 months in the T-DM1 and XL arms, respectively (HR = 0.382; CI: 0.184–0.795; P = 0.0081). Multivariate analysis adjusting for baseline risk factors produced similar results. Safety profiles of T-DM1 and XL in patients with CNS metastases at baseline (T-DM1 = 43; XL = 49) were consistent with those for the overall study population. Grade ≥3 adverse events (AEs) were reported in 17 (39.5%) patients in the T-DM1 arm and 29 (59.2%) patients in the XL arm. Serious AEs were reported in 5 (11.6%) and 11 (22.4%) patients in the T-DM1 and XL arms, respectively. No new safety signals were identified.

Conclusions

In this retrospective exploratory analysis of data from EMILIA, the rate of CNS progression in patients with or without baseline CNS metastases was low in both treatment arms. In the subset of patients with brain metastases at baseline, similar to the intent-to-treat population, T-DM1 was associated with significantly improved OS compared with XL. Prospective phase 3 trials are necessary to confirm these results.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-12-27.

Novel features of a PIWI-like protein homolog in the parasitic protozoan Leishmania

In contrast to nearly all eukaryotes, the Old World Leishmania species L. infantum and L. major lack the bona fide RNAi machinery genes. Interestingly, both Leishmania genomes code for an atypical Argonaute-like protein that possesses a PIWI domain but lacks the PAZ domain found in Argonautes from RNAi proficient organisms. Using sub-cellular fractionation and confocal fluorescence microscopy, we show that unlike other eukaryotes, the PIWI-like protein is mainly localized in the single mitochondrion in Leishmania. To predict PIWI function, we generated a knockout mutant for the PIWI gene in both L. infantum (Lin) and L. major species by double-targeted gene replacement. Depletion of PIWI has no effect on the viability of insect promastigote forms but leads to an important growth defect of the mammalian amastigote lifestage in vitro and significantly delays disease pathology in mice, consistent with a higher expression of the PIWI transcript in amastigotes. Moreover, amastigotes lacking PIWI display a higher sensitivity to apoptosis inducing agents than wild type parasites, suggesting that PIWI may be a sensor for apoptotic stimuli. Furthermore, a whole-genome DNA microarray analysis revealed that loss of LinPIWI in Leishmania amastigotes affects mostly the expression of specific subsets of developmentally regulated genes. Several transcripts encoding surface and membrane-bound proteins were found downregulated in the LinPIWI^(−/−) mutant whereas all histone transcripts were upregulated in the null mutant, supporting the possibility that PIWI plays a direct or indirect role in the stability of these transcripts. Although our data suggest that PIWI is not involved in the biogenesis or the stability of small noncoding RNAs, additional studies are required to gain further insights into the role of this protein on RNA regulation and amastigote development in Leishmania.

Abstract P5-18-24: Population pharmacokinetics of trastuzumab emtansine, a HER2-targeted antibody-drug conjugate, in patients with HER2-positive metastatic breast cancer: clinical implications of the effect of various covariates

Background: Trastuzumab emtansine (T-DM1) is a HER2-targeted antibody-drug conjugate composed of the humanized monoclonal antibody trastuzumab, the potent cytotoxic agent DM1 (a microtubule inhibitor), and a stable thioether linker. To estimate typical pharmacokinetic (PK) parameter values and interpatient variability, a population PK model for T-DM1 was previously developed from 1 phase 1 (0.3 to 4.8 mg/kg in qw or q3w regimens) and 2 phase 2 (3.6 mg/kg q3w) trials (Gupta, J Clin Pharmacol 2012). The model reported here has been updated with additional data from 2 randomized trials (phase 2 TDM4450g and phase 3 EMILIA, 3.6 mg/kg q3w). Another phase 2 trial (TDM4688g) was used for external validation of the model. The effect of demographic and pathophysiological covariates on the PK of T-DM1 was explored to better understand the clinical factors that might affect exposure and clinical outcome for individual patients.

Methods: For the current analysis, 9934 T-DM1 serum concentration-time data points from 671 patients were simultaneously fitted using NONMEM® software. T-DM1 concentration-time data to date are best described using a 2-compartment linear model. All relevant and plausible covariates likely to have an effect on T-DM1 systemic exposure, or likely to have clinical relevance, were explored for possible correlation with the key T-DM1 PK parameters of clearance (CL) and central volume of distribution (Vc). These covariates include those related to demographics, renal and hepatic function, disease status, and treatment history.

Results: The estimated CL for T-DM1 is 0.68 L/day, Vc is 3.13 L, and the terminal half-life is 3.94 days. Interindividual variability (IIV) of the base model is 25.6% and 17.5% for CL and Vc, respectively. Patients with greater body weight, sum of longest dimension of target lesions, serum concentration of shed HER2 extracellular domain, and aspartate aminotransferase concentrations, as well as patients with lower serum albumin and baseline trastuzumab concentrations, have statistically faster CL. Patients with greater body weight also have statistically larger Vc. Incorporation of these covariates (P&lt;0.001 by likelihood ratio test) decreased IIV of CL and Vc to 19.1% and 11.7%, respectively. All covariates together explain 44.4% and 55.8% of IIV in CL and Vc, respectively. The model sensitivity analysis suggests that a patient with a statistically significant PK covariate value at the 5th or 95th percentile of the population will have a &lt;20% difference in cumulative exposure (as represented by area under the T-DM1 concentration-time curve) compared with a typical patient with a median covariate value.

Conclusions: A relatively small IIV for the estimated T-DM1 PK parameters of CL and Vc was observed. None of the evaluated covariates had a clinically meaningful magnitude of effect on T-DM1 exposure (&lt;20% difference for patients with 5th and 95th percentiles vs patients with median value of covariates) that would justify a further dose adjustment. The body weight–based dose of 3.6 mg/kg q3w without further correction for other factors is considered appropriate in ongoing clinical trials.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-18-24.

Leishmania donovani: immunostimulatory cellular responses of membrane and soluble protein fractions of splenic amastigotes in cured patient and hamsters

Visceral leishmaniasis (VL), caused by the intracellular parasite Leishmania donovani, L. chagasi and L. infantum is characterized by defective cell-mediated immunity (CMI) and is usually fatal if not treated properly. An estimated 350 million people worldwide are at risk of acquiring infection with Leishmania parasites with approximately 500,000 cases of VL being reported each year. In the absence of an efficient and cost-effective antileishmanial drug, development of an appropriate long-lasting vaccine against VL is the need of the day. In VL, the development of a CMI, capable of mounting Th1-type of immune responses, play an important role as it correlate with recovery from and resistance to disease. Resolution of infection results in lifelong immunity against the disease which indicates towards the feasibility of a vaccine against the disease. Most of the vaccination studies in Leishmaniasis have been focused on promastigote- an infective stage of parasite with less exploration of pathogenic amastigote form, due to the cumbersome process of its purified isolation. In the present study, we have isolated and purified splenic amastigotes of L. donovani, following the traditional protocol with slight modification. These were fractionated into five membranous and soluble subfractions each i.e MAF1-5 and SAF1-5 and were subjected for evaluation of their ability to induce cellular responses. Out of five sub-fractions from each of membrane and soluble, only four viz. MAF2, MAF3, SAF2 and SAF3 were observed to stimulate remarkable lymphoproliferative, IFN-γ, IL-12 responses and Nitric Oxide production, in Leishmania-infected cured/exposed patients and hamsters. Results suggest the presence of Th-1 type immunostimulatory molecules in these sub-fractions which may further be exploited for developing a successful subunit vaccine from the less explored pathogenic stage against VL.

SABRE-B: an evaluation of paclitaxel and bevacizumab with or without sunitinib as first-line treatment of metastatic breast cancer

BACKGROUND

The vascular endothelial growth factor (VEGF) pathway can be targeted through VEGF neutralization or VEGF receptor (VEGFR) blockade using tyrosine kinase inhibition. Because laboratory models suggest that combining these approaches might be synergistic, we sought to evaluate the feasibility and efficacy of combining sunitinib with paclitaxel + bevacizumab (PB).

METHODS

Patients with human epidermal growth factor receptor 2 (HER2)-negative, metastatic breast cancer receiving first-line chemotherapy were randomized to PB or PB with sunitinib (PBS), with planned escalation of the sunitinib dose.

RESULTS

Forty-six patients were randomized to PB or PBS with sunitinib dosed at 25 mg p.o. daily. Patients receiving PBS encountered substantial toxicity that precluded adequate treatment. The percentage of patients with grade ≥3 adverse events was greater in the PBS arm than the PB arm (83% versus 57%), and sunitinib dosing was modified in 78% of patients, most often due to neutropenia, febrile neutropenia, and fatigue. In addition, 44% of patients had sunitinib dose reduction to 12.5 mg, and 39% required discontinuation. Patients receiving PBS had more bevacizumab treatment interruptions and discontinuations because of toxicity. Median treatment duration was longer in the PB arm compared with the PBS arm (14.1 versus 11.1 weeks), reflecting early treatment discontinuation of PBS. Because of poor tolerability of the addition of sunitinib to PB, the planned sunitinib dose escalation was halted and the study accrual was terminated.

CONCLUSION

Adding sunitinib to standard doses of bevacizumab plus paclitaxel for metastatic breast cancer is not feasible. Different strategies will be required to evaluate whether there is additional clinical benefit to combining VEGF/VEGFR-targeted agents.

Photodynamic vaccination of hamsters with inducible suicidal mutants of Leishmania amazonensis elicits immunity against visceral leishmaniasis

Leishmania, naturally residing in the phagolysosomes of macrophages, is a suitable carrier for vaccine delivery. Genetic complementation of these trypanosomatid protozoa to partially rectify their defective heme-biosynthesis renders them inducible with delta-aminolevulinate to develop porphyria for selective photolysis, leaving infected host cells unscathed. Delivery of released "vaccines" to antigen-presenting cells is thus expected to enhance immune response, while their self-destruction presents added advantages of safety. Such suicidal L. amazonensis was found to confer immunoprophylaxis and immunotherapy on hamsters against L. donovani. Neither heat-killed nor live parasites without suicidal induction were effective. Photodynamic vaccination of hamsters with the suicidal mutants reduced the parasite loads by 99% and suppressed the development of disease. These suppressions were accompanied by an increase in Leishmania-specific delayed-type hypersensitivity and lymphoproliferation as well as in the levels of splenic iNOS, IFN-gamma, and IL-12 expressions and of Leishmania-specific IgG2 in the serum. Moreover, a single intravenous administration of T cells from vaccinated hamsters was shown to confer on naïve animals an effective cellular immunity against L. donovani challenges. The absence of lesion development at vaccination sites and parasites in the draining lymphnodes, spleen and liver further indicates that the suicidal mutants provide a safe platform for vaccine delivery against experimental visceral leishmaniasis.

Th1-stimulatory polyproteins of soluble Leishmania donovani promastigotes ranging from 89.9 to 97.1 kDa offers long-lasting protection against experimental visceral leishmaniasis

Our earlier studies identified a fraction (F2) of Leishmania donovani soluble promastigote antigen belonging to 97.4-68 kDa for its ability to stimulate Th1-type cellular responses in cured visceral leishmaniasis (VL) patients as well as in cured hamsters. A further fractionation of F2-fraction into seven subfractions (F2.1-F2.7) and re-assessment for their immunostimulatory responses revealed that out of these, only four (F2.4-F2.7) belonging to 89.9-97.1 kDa, stimulated remarkable Th1-type cellular responses either individually or in a pooled form (P4-7). In this study these potential subfractions were further assessed for their prophylactic potential in combination with BCG against L. donovani challenge in hamsters. Optimum parasite inhibition ( approximately 99%) was obtained in hamsters vaccinated with pooled subfractions and they survived for 1 year. The protection was further supported by remarkable lymphoproliferative, IFN-gamma and IL-12 responses along with profound delayed type hypersensitivity and increased levels of Leishmania-specific IgG2 antibody as observed on days 45, 90 and 120 post-challenge suggesting that a successful subunit vaccine against VL may require multiple Th1-immunostimulatory proteins. MALDI-TOF-MS/MS analysis of these subfractions further revealed that of the 19 identified immunostimulatory proteins, Elongation factor-2, p45, Heat shock protein-70/83, Aldolase, Enolase, Triosephosphate isomerase, Disulfideisomerase and Calreticulin were the major ones in these subfractions.

Proteomic approaches for discovery of new targets for vaccine and therapeutics against visceral leishmaniasis

Visceral leishmaniasis (VL) is the most devastating type caused by Leishmania donovani, Leishmania infantum, and Leishmania chagasi. The therapeutic mainstay is still based on the antiquated pentavalent antimonial against which resistance is now increasing. Unfortunately, due to the digenetic life cycle of parasite, there is significant antigenic diversity. There is an urgent need to develop novel drug/vaccine targets against VL for which the primary goal should be to identify and characterize the structural and functional proteins. Proteomics, being widely employed in the study of Leishmania seems to be a suitable strategy as the availability of annotated sequenced genome of Leishmania major has opened the door for dissection of both protein expression/regulation and function. Advances in clinical proteomic technologies have enable to enhance our mechanistic understanding of virulence/pathogenicity/host-pathogen interactions, drug resistance thereby defining novel therapeutic/vaccine targets. Expression proteomics exploits the differential expression of leishmanial proteins as biomarkers for application towards early diagnosis. Further using immunoproteomics efforts were also focused on evaluating responses to define parasite T-cell epitopes as vaccine/diagnostic targets. This review has highlighted some of the relevant developments in the rapidly emerging field of leishmanial proteomics and focus on its future applications in drug and vaccine discovery against VL.

Age-influenced population kinetics and immunological responses of Leishmania donovani in hamsters

Susceptibility of animals to infections depends upon various factors including sex and age of the host, which plays a pivotal role. In this communication, we have investigated the "intake" of Leishmania donovani infection in young (3-4 weeks old) and adult (15-16 weeks old) golden hamsters. The splenic parasite load in young hamsters on day 15 post infection (p.i.) was 54 +/- 4 amastigotes/100 macrophage nuclei and increased to 106.3 +/- 3.5 on day 30 p.i. However, adult group showed 2.2-(P < 0.001) and 1.75-fold (P < 0.001) lesser parasite burden on these days, respectively. But as the disease progresses further, differences in parasite burden become less significant, as revealed by comparable levels of parasite loads at 2 months p.i. Spleen weight measurements correspond to the above observations. In the young group, the levels of antileishmanial antibody rise two and 4.5 times on days 15 and 30 p.i., respectively, as compared to only 1.3 and 2.3 times increase in their respective adult counterparts. However, after 2 months of infection both groups recorded analogous (12-fold) rise in antibody levels. Both mitogenic and antigenic responses in adult hamsters were less suppressed compared to young hamsters on days 15 and 30 p.i. However, both groups exhibited highly suppressed cell-mediated immune (CMI) responses after 2 months of infection. These findings implicate that age of the host may influence the susceptibility and resistance to Leishmania infection.

Proteophosphoglycan is differentially expressed in sodium stibogluconate-sensitive and resistant Indian clinical isolates of Leishmania donovani

Leishmania produce several types of mucin-like glycoproteins called proteophosphoglycans (PPGs) some of which are secreted while others are found on the surface of promastigotes and amastigotes. These proteins are thought to be important in the transmission, invasion and subsequent intracellular survival of parasites. The structure and function of PPGs are species and stage-specific in the case of L. major and L. mexicana, but no such information has hitherto been available for L. donovani. This study presents, for the first time, an initial characterization (localization) of PPG in sodium stibogluconate (SSG)-resistant and sensitive clinical isolates of L. donovani from Bihar (India) by confocal microscopy, flow cytometry and Western blotting using antibodies to L. major PPG. Confocal microscopy analysis revealed that both promastigotes and amastigotes possess PPG on their cell membrane and flagellar pocket membrane but its expression was variable in different isolates. The quantitative analysis by FACS and Western blotting showed that the expression and intensity of PPG bands was higher in SSG-resistant isolates. This study suggests the possibilities of involvement of PPG in drug-resistant mechanisms and of using PPG abundance as a marker for identifying drug-resistant clinical isolates in Indian kala azar.

In vitro and in vivo leishmanicidal activity of Dysoxylum binectariferum and its fractions against Leishmania donovani

The leishmanicidal effect of crude ethanolic extract of stem bark of Dysoxylum binectariferum and its fractions has been investigated against Leishmania donovani, the causative agent of visceral leishmaniasis. Ethanolic extract was lethal to promastigotes as well as amastigote forms in macrophage system at the concentration of 100 microg/ml. Chloroform fraction significantly inhibited promastigote multiplication and was also active against amastigotes in infected J774A.1 macrophages at 100 microg/ml. Hexane fraction was moderately active and the other fractions were inactive against both the forms. When tested in vivo in hamsters, ethanolic extract was toxic at 500 mg/kg whereas exhibited marginal activity (67.7+/-5.3%) at 250 mg/kg x 5, p.o. on day 7 post treatment (p.t.) which increases slightly (69+/-4.7) by day 30 p.t. Chloroform and n-hexane fractions exhibited 64.3+/-4% and 47.8+/-4.6% parasite inhibition at the dose of 100 mg/kg x 5 p.o., respectively. The pure compound, rohitukine, obtained from chloroform fraction showed weaker in vitro activity and was ineffective in infected hamsters. The lead potential of this plant need further investigations.

Atomic-beam alignment of inorganic materials for liquid-crystal displays

The technique used to align liquid crystals-rubbing the surface of a substrate on which a liquid crystal is subsequently deposited-has been perfected by the multibillion-dollar liquid-crystal display industry. However, it is widely recognized that a non-contact alignment technique would be highly desirable for future generations of large, high-resolution liquid-crystal displays. A number of alternative alignment techniques have been reported, but none of these have so far been implemented in large-scale manufacturing. Here, we report a non-contact alignment process, which uses low-energy ion beams impinging at a glancing angle on amorphous inorganic films, such as diamond-like carbon. Using this approach, we have produced both laptop and desktop displays in pilot-line manufacturing, and found that displays of higher quality and reliability could be made at a lower cost than the rubbing technique. The mechanism of alignment is explained by adopting a random network model of atomic arrangement in the inorganic films. Order is induced by exposure to an ion beam because unfavourably oriented rings of atoms are selectively destroyed. The planes of the remaining rings are predominantly parallel to the direction of the ion beam.