A pilot trial of Thymalfasin (Ta1) to prevent covid-19 infection and morbidities in renal dialysis patients: Preliminary report.

PURPOSE: Patients with end-stage renal disease (ESRD) on hemodialysis (HD) are considered particularly susceptible to infection with SARS-CoV2 on the basis of the immunodeficiency associated with advanced age, comorbidity burden, medication use, and need for frequent visits to dialysis clinics. In prior studies, thymalfasin (thymosin alpha 1, Ta1) has been shown to enhance antibody response to influenza vaccine and reduce influenza infection in geriatric populations, including hemodialysis patients, when used as an adjunct to influenza vaccine. Early in the COVID-19 pandemic we speculated that administration of Ta1 to HD patients would result in reduced rate and severity of COVID-19 infection. We also hypothesized that HD patients treated with Ta1 who did become infected with COVID-19 would have a milder course of infection in terms of hospitalization rates, requirement for and length of ICU stays, requirement for mechanical ventilation, and survival. Further, we proposed that patients who avoided COVID-19 infection during the study would have decreased non-COVID-19 infections and hospitalizations compared to controls. PROCEDURES: The study launched in January 2021 and, as of July 1, 2022, 254 ESRD/ HD patients from five dialysis centers in Kansas City, MO have been screened. Of these, 194 patients have been randomized 1:1 to either Group A (1.6 mg Ta1 given subcutaneously twice weekly for 8 weeks), or Group B (control group not receiving Ta1). After the 8-week treatment period, subjects were followed for an additional 4 months and monitored for safety and efficacy. A data safely monitoring board reviewed all reported adverse effects and commented on study progress. RESULTS: To date, only 3 deaths have occurred in subjects treated with Ta1 (Group A), compared to 7 in the control (Group B). There have been 12 COVID-19 related serious adverse effects (SAEs; 5 in Group A, and 7 in Group B). The majority of patients have received a COVID-19 vaccine (91 patients in group A, and 76 patients in Group B) at various times throughout the study. Nearing completion of the study, blood samples have been collected and antibody responses to COVID-19 will be analyzed along with safety and efficacy endpoints when all subjects have completed the study.

Evaluation of thymosin α 1 in nonclinical models of the immune-suppressing indications melanoma and sepsis.

OBJECTIVES: Recent understanding of the complex pathophysiology of melanoma and severe sepsis suggests that immune-modulating compounds such as thymosin alpha 1 (INN: thymalfasin; abbreviated Ta1) could be useful in the treatment of these two unrelated immune-suppressing indications. RESEARCH DESIGN AND METHODS: Three nonclinical murine models were utilized, including: i) a lung metastasis B16 model; ii) a B16-based tumor growth model; and iii) a cecal-ligation and puncture (CLP) sepsis model. RESULTS: In the lung metastasis model, Ta1 treatment alone led to a 32% decrease in metastases (p < 0.05). Additionally, combinations of Ta1 and an anti-PD-1 antibody led to significantly fewer metastases than vehicle. In the tumor growth model, significant decreases in tumor growth were seen: 34% (p = 0.015) to 46% (p = 0.001) depending on the Ta1 dose. In the CLP sepsis model, Ta1 treatment showed a positive trend towards increased survival and decreased bacterial load. In this CLP model, Ta1 also appeared to have an effect on the levels of some biomarkers. CONCLUSIONS: All three models demonstrated a benefit after treatment with Ta1, with no evidence of toxicity. These initial pilot studies support the hypothesis that immune-suppressive indications, including sepsis and melanoma, may be treated with Ta1 alone or by Ta1 in combination with other immunotherapies.

Thymosin α1 continues to show promise as an enhancer for vaccine response.

Thymosin α1 (Tα1) is an immune-modulating peptide that can be expected to improve response to vaccinations, as stimulated dendritic cells and T cells can act in concert to increase antibody production along with an improved cytotoxic response from the T cells themselves. Tα1 demonstrated efficacy in preclinical studies; subsequently, it was shown to enhance response to vaccinations in difficult-to-treat populations, including individuals immune suppressed due to age or hemodialysis, and leading to a decrease in later infections. During the 2009 pandemic outbreak of H1N1 influenza, mouse and ferret studies confirmed that the use of higher doses of Tα1 allowed for fewer injections than those used in the previous clinical studies. In addition, a clinical study with Focetria™ MF59-adjuvanted monovalent H1N1 vaccine showed that treatment with Tα1 twice provided an earlier and greater response to the vaccine (P < 0.01).

NMR structural studies of thymosin α1 and ß-thymosins.

Thymosin proteins, originally isolated from fractionation of thymus tissue, represent a class of compounds that we now know are present in numerous other tissues, are unrelated to each other in a genetic sense, and appear to have different functions within the cell. Thymosin α1 (generic drug name thymalfasin; trade name Zadaxin) is derived from a precursor molecule, prothymosin, by proteolytic cleavage, and stimulates the immune system. Although the peptide is natively unstructured in aqueous solution, the helical structure has been observed in the presence of trifluoroethanol or unilamellar vesicles, and these studies are consistent with the presence of a dynamic helical structure whose sides are not completely hydrophilic or hydrophobic. This helical structure may occur in circulation when the peptide comes into contact with membranes. In this report, we discuss the current knowledge of the thymosin α1 structure and similar properties of thymosin ß4 and thymosin ß9, in different environments.

NMR structure of human thymosin alpha-1.

800 MHz NMR structure of the 28-residue peptide thymosin alpha-1 in 40% TFE/60% water (v/v) has been determined. Restrained molecular dynamic simulations with an explicit solvent box containing 40% TFE/60% TIP3P water (v/v) were used, in order to get the 3D model of the NMR structure. We found that the peptide adopts a structured conformation having two stable regions: an alpha-helix region from residues 14 to 26 and two double ß-turns in the N-terminal twelve residues which form a distorted helical structure.

Personalized medicine for mucositis: Bayesian networks identify unique gene clusters which predict the response to gamma-D-glutamyl-L-tryptophan (SCV-07) for the attenuation of chemoradiation-induced oral mucositis.

Gamma-D-glutamyl-L-tryptophan (SCV-07) demonstrated an overall efficacy signal in ameliorating oral mucositis (OM) in a clinical trial of head and neck cancer patients. However, not all SCV-07-treated subjects responded positively. Here we determined if specific gene clusters could discriminate between subjects who responded to SCV-07 and those who did not. Microarrays were done using peripheral blood RNA obtained at screening and on the last day of radiation from 28 subjects enrolled in the SCV-07 trial. An analytical technique was applied that relied on learned Bayesian networks to identify gene clusters which discriminated between individuals who received SCV-07 and those who received placebo, and which differentiated subjects for whom SCV-07 was an effective OM intervention from those for whom it was not. We identified 107 genes that discriminated SCV-07 responders from non-responders using four models and applied Akaike Information Criteria (AIC) and Bayes Factor (BF) analysis to evaluate predictive accuracy. AIC were superior to BF: the accuracy of predicting placebo vs. treatment was 78% using BF, but 91% using the AIC score. Our ability to differentiate responders from non-responders using the AIC score was dramatic and ranged from 93% to 100% depending on the dataset that was evaluated. Predictive Bayesian networks were identified and functional cluster analyses were performed. A specific 10 gene cluster was a critical contributor to the predictability of the dataset. Our results demonstrate proof of concept in which the application of a genomics-based analytical paradigm was capable of discriminating responders and non-responders for an OM intervention.

Thymosin alpha 1: past clinical experience and future promise.

Thymosin alpha 1, originally isolated as the compound responsible for reconstitution of immune function in thymectomized animal models, has enjoyed a wide-ranging clinical development program over the past decades, extending across multiple companies, indications, countries, and continents. This paper provides an overview of this complex picture. The extensive clinical studies began with small studies conducted with an impure mixture of peptides under the aegis of physician-sponsored INDs submitted to the US FDA, in subjects with primary immune deficiency such as DiGeorge syndrome. Subsequent studies ranged all the way to large phase-3 trials conducted with synthetically produced thymosin alpha 1 and hundreds of patients, in many countries including the United States, Italy, and China.

An immunomodulating dipeptide, SCV-07, is a potential therapeutic for recurrent genital herpes simplex virus type 2 (HSV-2).

Herpes simplex virus type 2 (HSV-2) infections produce a recurrent disease state associated with susceptibility to other pathogens, including human immunodeficiency virus (HIV), and cannot be cured by current therapeutic treatments. The HSV-2 epidemic must therefore be addressed by therapeutic strategies that reduce recurrent lesions and ideally lack the possibility for development of drug resistance. To this end, the therapeutic potential of SCV-07 (gamma-D-glutamyl-L-tryptophan), a synthetic dipeptide with potent immunomodulatory and antimicrobial activity, was studied in the guinea pig model of recurrent genital HSV-2. Initial evaluations showed that when delivered orally, but not subcutaneously, SCV-07 significantly reduced recurrent lesions. Oral dose ranging studies indicated that, of the tested amounts, 5microg/kg was optimal when delivered after an overnight fast. Interestingly, fasting induced a significant increase in recurrent lesions in vehicle-treated guinea pigs relative to non-fasted animals. Despite this increase, SCV-07 significantly reduced lesion formation in treated animals but showed no durability following cessation of treatment. In fact, this regimen of SCV-07 treatment produced statistically indistinguishable outcomes compared with those provided by topical aciclovir. These data illustrate that SCV-07 may provide an easily administered alternative or supplemental treatment option for genital HSV-2 recurrent disease.

Issues in pharmaceutical development of thymosin alpha1 from preclinical studies through marketing.

SciClone Pharmaceuticals licensed the commercial and patent rights to thymosin alpha1, for geographical regions of the world excluding the United States and Europe, in the early 1990s. With this license, SciClone embarked on global drug development, and the issues encountered for thymosin alpha1 are reflective of the roller coaster of modern approval of pharmaceuticals. Most of the required toxicology studies had been completed prior to licensure, but some newer studies had to be conducted to obtain approvals in certain countries. The recent development of the "International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use" (ICH) guidelines allows for a clearer definition of the required battery of toxicology studies, although some countries still have not adopted these guidelines, and the local regulations have had to be understood and followed. Other hurdles include the complications that manufacturing requirements can differ between countries, and certain countries require local clinical experience trials in addition to SciClone's cumulative clinical data. A further obstacle was the pleiotropic nature of the mechanism of action of thymosin alpha1, with the resulting difficulty in the unraveling of its pharmacologic effects. With close attention to these regulatory details, SciClone has obtained approvals in more than 30 countries and has successfully begun commercial sales.

Signaling pathways leading to the activation of IKK and MAPK by thymosin alpha1.

Thymosin alpha 1 (Talpha1) has therapeutic potential in the treatment of infectious diseases and cancer. However, the exact molecular pathways for Talpha1 action are not fully understood. We found that Talpha1 induces the production of interleukin-6 (IL-6), IL-10, and IL-12 in murine bone marrow-derived macrophages (BMDMs) through IKK and MAPK pathways. Talpha1 triggers the activation of AP-1 and the phosphorylation of JNK and p38. Inhibition of p38 impairs IL-6 production in response to Talpha1. Further, TRAF6 is involved in the activation of JNK and IRAK4 is involved for the activation of IKK and PKCzeta in a Talpha1-induced system. Loss of IRAK4 largely blocked induction of IL-6. Thus, our studies define early signal events that are critical for the Talpha1-induced immune responses.

Activation of IKK by thymosin alpha1 requires the TRAF6 signalling pathway.

Thymosin alpha1 (T(alpha)1) is noted for its immunomodulatory activities and therapeutic potential in treatment of infectious diseases and cancer. However, the molecular mechanism of its effectiveness is not completely understood. Here, we report that T(alpha)1 induces interleukin (IL)-6 expression through the I(kappa)B kinase (IKK) and nuclear factor-(kappa)B (NF-(kappa)B) pathway. Using IKK(beta)-deficient bone-marrow-derived macrophages and mouse embryo fibroblasts (MEFs), we show that IKK(beta) is essential for IKK and NF-(kappa)B activation as well as efficient IL-6 induction. Further analysis using tumour necrosis factor receptor-associated factor 6 (TRAF6)-deficient MEFs shows that TRAF6 is crucial for activation of IKK and induction of IL-6 by Talpha1. Intriguingly, T(alpha)1 triggers protein kinase C (PKC)iota/zeta activation, which is TRAF6 dependent and involves IKK. In addition, T(alpha)1 induces the formation of a signalsome composed of TRAF6, p62 and PKC(iota)/zeta as well as IKK. Thus, our study identifies T(alpha)1 as a unique activator of the TRAF6 signal pathway and provides a cohesive interpretation of the molecular basis of the therapeutic utility of T(alpha)1.

Biological Activity of Peptide SCV-07 Against Murine Tuberculosis.

SCV-07 (gamma-glutamyl-tryptophan) is a new immunomodulatory compound that was developed and patented both for composition and immunomodulatory use. SCV-07 was shown to have a broad spectrum of immunostimulatory activities both in vitro and in vivo. In the present study we investigated the biological activity of SCV-07 in a murine model of experimental tuberculosis (TB) induced with M. bovis-bovinus 8 strain. Therapy with SCV-07 at doses of 0.01, 0.1, and 1 &mgr;g/kg (5 daily injections) decreased the lung damage index compared to untreated controls and to those treated with isoniazid alone. The growth of M. bovis-bovinus 8 in spleen culture was decreased. Cytokine studies showed that on the 24th day after the treatment with SCV-07 the production of IL-2 was restored to the level seen in uninfected animals. Proliferative responses for both thymic and spleen cells were nearly restored to the responses observed in uninfected animals. IFN-gamma production by both thymic and spleen cells, as well as its circulating levels in serum, was increased by the SCV-07 treatment. Concurrently, IL-4 production was decreased in the same cell types and the serum. These changes suggest that SCV-07 is stimulating a shift of T helper cells to a Th1-like immune response. SCV-07 treatment also stimulated the macrophage functions, which had been decreased by tuberculosis infection and isoniazid therapy, with an improved phagocytosis activity of peritoneal macrophage. The obtained results suggest that SCV-07 treatment increases the efficacy of anti-tuberculosis therapy as well as the strength of the immune response. Thus, SCV-07 is a prospective immunomodulator for a complex therapy of TB.

Thymosin alpha1 inhibits mammary carcinogenesis in Fisher rats.

The effects of thymosin alpha1 (Talpha1) on mammary carcinogenesis was investigated in Fisher rats. Mammary carcinomas were observed 3 months after N-nitrosomethylurea (NMU) injection (10mg, i.p.) into Fisher rats. Daily administration of Talpha1 (10 microg, s.c.) reduced mammary carcinoma incidence and prolonged survival time. Animals treated with exogenous Talpha1 had a significantly greater blood white cell density than control Fisher rats. These results suggest that Talpha1 prevents mammary carcinoma incidence as a result of stimulation of the immune system.

A phase I randomized, multicenter trial of CPX in adult subjects with mild cystic fibrosis.

CPX (8-cyclopentyl-1,3-dipropylxanthine) is a novel compound currently under development as a potential treatment for cystic fibrosis (CF). The drug has been shown to increase chloride efflux and CFTR trafficking in vitro in CF airway cells. This phase I multicenter, single-dose, placebo-controlled trial was performed at four institutions. Thirty-seven subjects homozygous for the Delta F(508) allele were studied in an escalating dose protocol of seven single-dose cohorts (1, 3, 10, 30, 100, 300, and 1,000 mg) to evaluate the safety, pharmacokinetics, and efficacy of CPX. Efficacy was determined using nasal transepithelial potential difference and sweat chloride measurements prior to dosing and at 1, 2, and 4 hr postdose. The incidence of adverse events in the treatment group was similar to that with placebo, indicating safety of the single doses studied. One serious adverse event (an acute pulmonary exacerbation) occurred 13 days after dosing, and was not considered related to the study drug. The maximal plasma CPX concentration and total amount of CPX absorbed appeared to be linearly related to dose, but was highly variable throughout the dose range studied, suggesting inconsistent absorption. There was no apparent effect of single-dose administration on either nasal transepithelial potential difference or sweat chloride measurements. The positive safety and pharmacokinetic findings of this study support continued development of CPX as a potential therapeutic for CF.