Itolizumab,a novel anti-CD6 monoclonal antibody: a safe and efficacious biologic agent for management of psoriasis

Introduction: Psoriasis, a chronic immune-mediated skin disorder is associated with significant physical, psychological, and quality of life impairments. Along with well-documented genetic and environmental factors, immunological factors also contribute to the pathogenesis of psoriasis. Among the immunological factors, CD6 – dependent T-cell proliferation to form Th1 and Th17 cells play a major role in the pathogenesis of psoriasis. Itolizumab is the first humanized IgG1 monoclonal antibody, which selectively targets CD6.

Areas covered: The current article presents the pharmacology of itolizumab and provides a review of the currently available data on the efficacy and safety of itolizumab for management of moderate to severe plaque psoriasis.

Expert opinion: The use of biologics to attenuate the immune-mediated pathological events in psoriasis is a relatively well-established clinical practice. However, the safety and efficacy of biologics continues to be an unsettled topic of ongoing research. While available data seems to suggest that itolizumab may be a safer option, additional studies with higher sample sizes and active comparators are needed before definitive conclusions can be drawn on the place of itolizumab in the management of psoriasis.     

Safety assessment of lutein and zeaxanthin (Lutemax™ 2020): Subchronic toxicity and mutagenicity studies

Lutein and zeaxanthin, naturally occurring carotenoids, have shown to reduce the risk of cataracts and age-related macular degeneration. Lutemax™ 2020 is a lutein and zeaxanthin (including meso-isomer) enriched product obtained from Marigold flowers (Tagetes erecta L). The objective of the present study was to investigate adverse effects, if any, of Lutemax 2020™ in acute and subchronic toxicity, and mutagenicity studies. In acute toxicity study in rats no lethality was noted at 2000 mg Lutemax 2020™/kg body weight (bw). In the subchronic study, Wistar rats (10/sex/group) were administered (gavage) lutein/zeaxanthin concentrate at dose levels of 0, 4, 40 and 400 mg/kg bw/day for 90-days. Compared with the control group, administration of lutein/zeaxanthin concentrate did not result in any toxicologically significant treatment-related changes in clinical observations, ophthalmic examinations, body weights, body weight gains, feed consumption, and organ weights. No toxicologically relevant findings were noted in urinalysis, hematology or clinical biochemistry parameters at the end of the treatment or recovery period. Terminal necropsy did not reveal any treatment-related gross or histopathology findings. The results of mutagenicity testing in Salmonella typhimurium did not reveal any genotoxicity. The no observed-adverse-effect level (NOAEL) for lutein/zeaxanthin concentrate was determined as 400 mg/kg bw/day, the highest dose tested.     

Antileishmanial efficacy of fluconazole and miltefosine in combination with an immunomodulator—picroliv

The chemotherapy of visceral leishmaniasis (VL) has several limitations including resistance and toxicity of the existing drugs. Downregulation of immune system further aggravates the problems. To combat this situation, leishmanicidal efficacy of already marketed standard antifungal drug, fluconazole under the approach of “therapeutic switching” in combination with standard antileishmanial drug, miltefosine, and a potent immunomodulator agent, picroliv, were evaluated in hamsters infected with Leishmania donovani. Animals treated with fluconazole (50 mg/kg × 5 days, oral (p.o.)) + miltefosine (5 mg/kg × 5 days, p.o.) showed enhancement in antileishmanial efficacy (77%), reactive nitrogen species, reactive oxygen species, hydrogen peroxide, and phagocytosis index as compared to those treated with individual drugs. Addition of picroliv to this combination further increased the antileishmanial efficacy from 77% to 88%. Upregulation of cell-mediated immunity was also observed in animals of this group which strengthens the immunomodulatory role of picroliv. These findings suggest a new option for antileishmanial chemotherapy at lower cost and toxicity.     

Age-influenced population kinetics and immunological responses of <Emphasis Type="Italic">Leishmania donovani</Emphasis> 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.     

Inhibition of transforming growth factor-beta1 signaling attenuates ataxia telangiectasia mutated activity in response to genotoxic stress

Ionizing radiation causes DNA damage that elicits a cellular program of damage control coordinated by the kinase activity of ataxia telangiectasia mutated protein (ATM). Transforming growth factor beta (TGFbeta)-1, which is activated by radiation, is a potent and pleiotropic mediator of physiologic and pathologic processes. Here we show that TGFbeta inhibition impedes the canonical cellular DNA damage stress response. Irradiated Tgfbeta1 null murine epithelial cells or human epithelial cells treated with a small-molecule inhibitor of TGFbeta type I receptor kinase exhibit decreased phosphorylation of Chk2, Rad17, and p53; reduced gammaH2AX radiation-induced foci; and increased radiosensitivity compared with TGFbeta competent cells. We determined that loss of TGFbeta signaling in epithelial cells truncated ATM autophosphorylation and significantly reduced its kinase activity, without affecting protein abundance. Addition of TGFbeta restored functional ATM and downstream DNA damage responses. These data reveal a heretofore undetected critical link between the microenvironment and ATM, which directs epithelial cell stress responses, cell fate, and tissue integrity. Thus, Tgfbeta1, in addition to its role in homoeostatic growth control, plays a complex role in regulating responses to genotoxic stress, the failure of which would contribute to the development of cancer; conversely, inhibiting TGFbeta may be used to advantage in cancer therapy.