A randomized controlled trial of thymalfasin plus transarterial chemoembolization for unresectable hepatocellular carcinoma

Recent advances and applications of peptide-agent conjugates for targeting tumor cells

BACKGROUND

Cancer, being a complex disease, presents a major challenge for the scientific and medical communities. Peptide therapeutics have played a significant role in different medical practices, including cancer treatment.

METHOD

This review provides an overview of the current situation and potential development prospects of anticancer peptides (ACPs), with a particular focus on peptide vaccines and peptide-drug conjugates for cancer treatment.

RESULTS

ACPs can be used directly as cytotoxic agents (molecularly targeted peptides) or can act as carriers (guiding missile) of chemotherapeutic agents and radionuclides by specifically targeting cancer cells. More than 60 natural and synthetic cationic peptides are approved in the USA and other major markets for the treatment of cancer and other diseases. Compared to traditional cancer treatments, peptides exhibit anticancer activity with high specificity and the ability to rapidly kill target cancer cells. ACP's target and kill cancer cells via different mechanisms, including membrane disruption, pore formation, induction of apoptosis, necrosis, autophagy, and regulation of the immune system. Modified peptides have been developed as carriers for drugs, vaccines, and peptide-drug conjugates, which have been evaluated in various phases of clinical trials for the treatment of different types of solid and leukemia cancer.

CONCLUSIONS

This review highlights the potential of ACPs as a promising therapeutic option for cancer treatment, particularly through the use of peptide vaccines and peptide-drug conjugates. Despite the limitations of peptides, such as poor metabolic stability and low bioavailability, modified peptides show promise in addressing these challenges. Various mechanism of action of anticancer peptides. Modes of action against cancer cells including: inducing apoptosis by cytochrome c release, direct cell membrane lysis (necrosis), inhibiting angiogenesis, inducing autophagy-mediated cell death and immune cell regulation.

Thymus-derived hormonal and cellular control of cancer

The thymus gland is a central lymphoid organ in which developing T cell precursors, known as thymocytes, undergo differentiation into distinct type of mature T cells, ultimately migrating to the periphery where they exert specialized effector functions and orchestrate the immune responses against tumor cells, pathogens and self-antigens. The mechanisms supporting intrathymic T cell differentiation are pleiotropically regulated by thymic peptide hormones and cytokines produced by stromal cells in the thymic microenvironment and developing thymocytes. Interestingly, in the same way as T cells, thymic hormones (herein exemplified by thymosin, thymulin and thymopoietin), can circulate to impact immune cells and other cellular components in the periphery. Evidence on how thymic function influences tumor cell biology and response of patients with cancer to therapies remains unsatisfactory, although there has been some improvement in the knowledge provided by recent studies. Herein, we summarize research progression in the field of thymus-mediated immunoendocrine control of cancer, providing insights into how manipulation of the thymic microenvironment can influence treatment outcomes, including clinical responses and adverse effects of therapies. We review data obtained from clinical and preclinical cancer research to evidence the complexity of immunoendocrine interactions underpinning anti-tumor immunity.

[Status Quo and Development of Immunotherapy for Hepatocellular Carcinoma]

Liver cancer is a serious global health problem and a common cause of cancer-related death. Hepatocellular carcinoma (HCC) is a common pathological type of liver cancer. The clinical symptoms of early HCC tend to be not obvious and 50% of HCC patients are already in the advanced stage by the time they are diagnosed. Systemic therapy is recommended for the treatment of advanced HCC. With the development of molecular targeted drugs (sorafenib and lenvatinib), some progress has been made in the systemic treatment of advanced HCC, but there is only modest benefit for the survival of HCC patients. In recent years, the emergence of immune checkpoint inhibitors has changed the overall outlook of HCC treatment, providing more possibilities for precise treatment of HCC and showing better treatment outcomes. In particular, the combination therapy of atezolizumab and bevacizumab significantly improved the survival outcomes in HCC patients. In addition, adoptive cell therapy, tumor vaccine, oncolytic viruses, and nonspecific immunotherapy have also emerged as strategies for immunotherapy. Herein, the status quo and development of HCC immunotherapy are reviewed.

Thymosin alpha-1 therapy improves postoperative survival after curative resection for solitary hepatitis B virus-related hepatocellular carcinoma: A propensity score matching analysis

Thymosin alpha-1 (Tα1) is an immunomodulatory and antiviral agent with potential effects on chronic hepatitis B and liver cancer. Its impact on solitary hepatocellular carcinoma (HCC) remains controversial, so we aimed to investigate the efficacy of Tα1 in solitary HBV-related HCC patients after curative resection.Between May 2010 and April 2016, 468 patients with solitary HBV-related HCC after curative resection were analyzed. Propensity score matching (PSM) was used to minimize confounding variables. Risk factors were identified by the Cox proportional hazards model. Recurrence-free survival (RFS) rates, overall survival (OS) rates, immunological, and virologic response were compared.The median follow up was 60.0 months. Immunological response improved in the Tα1 group compared with the control group (P < .001) but the virologic response was similar between 2 groups after 24 months. Patients with Tα1 therapy had better RFS and OS before (P = .018 and P < .001) and after (P = .006 and P < .001) propensity matching. Multivariate analysis revealed that Tα1 therapy was an independent prognostic factor for both OS (P < .001, HR = 0.308, 95% CI: 0.175-0.541) and RFS (P < .001, HR = 0.381, 95% CI: 0.229-0.633).Tα1 as an adjuvant therapy improves the prognosis of solitary HBV-related HCC patients after curative liver resection.

Thymosin alpha-1 blocks the accumulation of myeloid suppressor cells in NSCLC by inhibiting VEGF production

BACKGROUND

Thymosin alpha-1 (TA) has been reported to inhibit tumor growth as an immunomodulator. However, its mechanism of action in immunosuppressive cells is unclear. The purpose of this study was to investigate whether TA can reshape the immune microenvironment by inhibiting the function of myeloid-derived suppressor cells (MDSCs) in non-small cell lung carcinoma (NSCLC).

METHODS

The effects of TA on peripheral blood monocytic MDSCs (M-MDSCs) in patients with NSCLC and on the apoptosis and migration of M-MDSCs were studied. A mouse subcutaneous xenograft tumor model was constructed, and the effect of TA on M-MDSC migration was evaluated. Quantitative real-time PCR, Western blotting, flow cytometry and immunohistochemistry were used to examine the mechanism by which TA affects M-MDSCs.

RESULTS

TA not only promoted the apoptosis of M-MDSCs by reducing the Bcl-2/BAX ratio but also and more importantly inhibited the migration of MDSCs to the tumor microenvironment by suppressing the production of vascular endothelial growth factor (VEGF) through the downregulation of hypoxia-inducible factor (HIF)-1α in tumor cells.

CONCLUSIONS

TA may have a novel antitumor effect mediated by decreasing M-MDSC accumulation in the tumor microenvironment through reduced VEGF production.

A Reappraisal of Thymosin Alpha1 in Cancer Therapy

Thymosin alpha1 (Tα1), an endogenous peptide first isolated from the thymic tissue in the mid-sixties, has gained considerable attention for its immunostimulatory activity that led to its application to diverse pathological conditions, including cancer. Studies in animal models and human patients have shown promising results in different types of malignancies, especially when Tα1 was used in combination with other chemo- and immune therapies. For this reason, the advancements in our knowledge on the adjuvant role of Tα1 have moved in parallel with the development of novel cancer therapies in a way that Tα1 was integrated to changing paradigms and protocols, and tested for increased efficacy and safety. Cancer immunotherapy has recently experienced a tremendous boost following the development and clinical application of immune checkpoint inhibitors. By unleashing the full potential of the adaptive immune response, checkpoint inhibitors were expected to be very effective against tumors, but it soon became clear that a widespread and successful application was not straightforward and shortcomings in efficacy and safety clearly emerged. This scenario led to the development of novel concepts in immunotherapy and the design of combination protocols to overcome these limitations, thus opening up novel opportunities for Tα1 application. Herein, we summarize in a historical perspective the use of Tα1 in cancer, with particular reference to melanoma, hepatocellular carcinoma and lung cancer. We will discuss the current limitations of checkpoint inhibitors in clinical practice and the mechanisms at the basis of a potential application of Tα1 in combination protocols.

Clinical efficacy and safety of synthetic thymic peptides with chemotherapy for non-small cell lung cancer in China: A systematic review and meta-analysis of 27 randomized controlled trials following the PRISMA guidelines

BACKGROUND

Synthetic thymic peptides (sTPs) are used with chemotherapy to treat non-small cell lung cancer (NSCLC). In this study, we have performed a systematic review and meta-analysis of published trials to confirm the clinical efficacy and safety of sTPs, and determine the optimal types, usages, and sTP/chemotherapy combinations to produce the desired responses.

MATERIALS AND METHODS

We collected all studies regarding combined sTP therapy and chemotherapy for NSCLC from the Chinese and English databases (up to October 2018). Bias risk was evaluated for each. Data for meta-analysis was extracted using a pre-designed form. Evidence quality was rated using the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS

We included 27 randomized controlled trials containing 1925 patients, most with unclear bias risk. Combining sTPs with chemotherapy significantly increased the objective response rate [1.28, (1.13 to 1.45)], disease control rate [1.10, (1.01 to 1.18)], quality of life (QOL) [2.05, (1.62, 2.60)], and 1-year overall survival rate [1.43, (1.15 to 1.78)], with decreased risks of neutropenia, thrombocytopenia, and gastrointestinal reactions. Optimal conditions included treatment in combination with gemcitabine or navelbine and cisplatin, twice a week, with one 3-week cycle. In these conditions, thymosin α1 improved both antitumor immunity and tumor response. Most results had good robustness, and their quality ranged from moderate to very low.

CONCLUSIONS

The results suggest that treatment with sTPs, especially thymosin α1, and concomitant chemotherapy is beneficial to the patient, and provide evidence for optimal treatment regimens that may increase patient QOL and survival.

Multidisciplinary management of recurrent and metastatic hepatocellular carcinoma after resection: an international expert consensus

Hepatocellular carcinoma (HCC) is the sixth-most common cancer and the third leading cause of cancer-related death in the world. However, 40-70% patients eventually suffer from postoperative recurrence within 5 years. HCC recurrence after surgery severely affects prognosis of the patients. Nevertheless, there is an opportunity to improve patients' prognosis if doctors and researchers can recognize the importance of a standardized perioperative management and study it in clinical and pre-clinical settings. Hence, based on our own experience and published studies from other researchers, we develop this consensus regarding multidisciplinary management of locally recurrent and metastatic hepatocellular carcinoma after resection. This consensus consists of the entire course of recurrent hepatocellular carcinoma (RHCC) management, including prediction of recurrence, prevention, diagnosis, treatment and surveillance of RHCC. Consensus recommendations are presented with grades of evidences (Ia, Ib, IIa, IIb, III and IV), and strength of recommendations (A, B, C, D and E). We also develop a decision-making path for RHCC treatment, which can intuitively demonstrate the management for RHCC. It is hoped that we may make some effort to standardize the management of RHCC and ultimately understand how to improve outcomes.

Thymalfasin, a promising adjuvant therapy in small hepatocellular carcinoma after liver resection

There is limited information available concerning the effect of thymalfasin (Tα1) as an adjuvant therapy in hepatocellular carcinoma (HCC) patient who received liver resection. The present study aimed to evaluate whether Tα1 can improve the prognosis of small HCC patients after liver resection.A total of 206 patients with small HCC who underwent liver resection were analyzed in our retrospective cohort study. Patients were divided into 2 groups: group A (resection + Tα1, n = 44) and group B (resection, n = 162). Clinical data, overall survival (OS), and recurrence-free survival (RFS) were compared. Prognostic factors were identified using multivariate analysis.After a median follow-up of 47.0 months, 134 patients (65%) had recurrence, and 62 patients (30.09%) died. The 1, 3, and 5-year OS rate of patients in group A was 97.7%, 90.6%, and 82.9%, respectively, and 95.1%, 80.5%, and 62.9%, respectively, for patients in group B (P = .014). The 1, 3, and 5-year RFS rate of patients in group A was 70.5%, 56.8%, and 53.3%, respectively, and 65.8%, 41.3%, and 32.1%, respectively, for patients in group B (P = .015). Multivariate analysis indicated that Tα1 was an independent prognostic factor for both OS (P = .015, hazard ratio 0.349, 95% confidence interval 0.149-0.816) and RFS (P = .019, hazard ratio 0.564, 95% confidence interval 0.349-0.910).Tα1 as an adjuvant therapy after liver resection may improve the prognosis of small HCC patients after liver resection.

Management of people with intermediate-stage hepatocellular carcinoma: an attempted network meta-analysis

BACKGROUND

There is significant uncertainty in the treatment of intermediate-stage hepatocellular carcinoma which is defined by the Barcelona Clinic Liver Cancer (BCLC) as hepatocellular carcinoma stage B with large, multi-nodular, Child-Pugh status A to B, performance status 0 to 2, and without vascular occlusion or extrahepatic disease.

OBJECTIVES

To assess the comparative benefits and harms of different interventions used in the treatment of intermediate-stage hepatocellular carcinoma (BCLC stage B) through a network meta-analysis and to generate rankings of the available interventions according to their safety and efficacy. However, we found only one comparison. Therefore, we did not perform the network meta-analysis, and we assessed the comparative benefits and harms of different interventions versus each other, or versus placebo, sham, or no intervention (supportive treatment only) using standard Cochrane methodology.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Science Citation Index Expanded, World Health Organization International Clinical Trials Registry Platform, and randomised clinical trials registers to September 2016 to identify randomised clinical trials on hepatocellular carcinoma.

SELECTION CRITERIA

We included only randomised clinical trials, irrespective of language, blinding, or publication status, in participants with intermediate-stage hepatocellular carcinoma, irrespective of the presence of cirrhosis, size, or number of the tumours (provided they met the criteria of intermediate-stage hepatocellular carcinoma), of presence or absence of portal hypertension, of aetiology of hepatocellular carcinoma, and of the future remnant liver volume. We excluded trials which included participants who had previously undergone liver transplantation. We considered any of the various interventions compared with each other or with no active intervention (supportive treatment only). We excluded trials which compared variations of the same intervention: for example, different methods of performing transarterial chemoembolisation.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We calculated the hazard ratio (HR) with 95% confidence intervals (CI) using both fixed-effect and random-effects models based on available-participant analysis with Review Manager. We assessed risk of bias according to Cochrane, controlled risk of random errors with Trial Sequential Analysis using Stata, and assessed the quality of the evidence using GRADE.

MAIN RESULTS

Three randomised clinical trials, including 430 participants, met the inclusion criteria for this review; however, data from two trials with 412 participants could be included in only one primary outcome (i.e. mortality). All three trials were at high risk of bias. All three trials included supportive care as cointervention. The comparisons included in the two trials reporting on mortality were: systemic chemotherapy with sorafenib versus no active intervention; and transarterial chemoembolisation plus systemic chemotherapy with sorafenib versus transarterial chemoembolisation alone. The trials did not report the duration of follow-up; however, it appeared that the participants were followed up for a period of about 18 to 30 months. The majority of the participants in the trials had cirrhotic livers. The trials included participants with intermediate-stage hepatocellular carcinoma arising from viral and non-viral aetiologies. The trials did not report the portal hypertension status of the participants. The mortality was 50% to 70% over a median follow-up period of 18 to 30 months. There was no evidence of difference in mortality at maximal follow-up between systemic chemotherapy versus no chemotherapy (hazard ratio 0.85, 95% CI 0.60 to 1.18; participants = 412; studies = 2; I² = 0%; very low quality evidence). A subgroup analysis performed by stratifying the analysis by the presence or absence of transarterial chemoembolisation as cointervention did not alter the results. None of the trials reported on serious adverse events other than mortality, health-related quality of life, recurrence of hepatocellular carcinoma, or length of hospital stay. One of the trials providing data was funded by the pharmaceutical industry, the other did not report the source of funding, and the trial with no data for the review was also funded by the pharmaceutical industry. We found two ongoing trials.

AUTHORS' CONCLUSIONS

Currently, there is no evidence from randomised clinical trials that people with intermediate-stage hepatocellular carcinoma would benefit from systemic chemotherapy with sorafenib either alone or when transarterial chemoembolisation was used as a cointervention (very low quality evidence). We need high-quality randomised clinical trials designed to measure differences in clinically important outcomes (e.g. all-cause mortality or health-related quality of life).

Immune Modulation with Thymosin Alpha 1 Treatment

Thymosin alpha 1 (Ta1) is a peptide originally isolated from thymic tissue as the compound responsible for restoring immune function to thymectomized mice. Ta1 has a pleiotropic mechanism of action, affecting multiple immune cell subsets that are involved in immune suppression. Ta1 acts through Toll-like receptors in both myeloid and plasmacytoid dendritic cells, leading to activation and stimulation of signaling pathways and initiation of production of immune-related cytokines. Due to the immune stimulating effects of Ta1, the compound would be expected to show utility for treatment of immune suppression, whether related to aging or to diseases such as infection or cancer. Extensive studies in both the preclinical and clinical setting will be summarized in the subsequent sections. These studies have demonstrated improvements in immune system cell subsets and the potential of Ta1 for the treatment of a range of diseases.

Thymosin alpha 1 suppresses proliferation and induces apoptosis in breast cancer cells through PTEN-mediated inhibition of PI3K/Akt/mTOR signaling pathway

Thymosin alpha 1 (Tα1), an immunoactive peptide, has been shown to inhibit cell proliferation and induce apoptosis in human leukemia, non-small cell lung cancer, melanoma, and other human cancers. However, the response and molecular mechanism of breast cancer cells exposed to Tα1 remain unclear. PTEN, a tumor suppressor gene, is frequently mutated in a variety of human cancers. In the present study, we aimed to investigate the biological roles of PTEN in the growth inhibition of human breast cancer cells exposed to Tα1. Using wild-type and mutant PTEN-expressing cells, we found a strong correlation between PTEN status and Tα1-mediated growth inhibition of breast cancer cells. The growth inhibition effect was more pronounced in breast cancer cells in which Tα1 enhanced PTEN expression, whereas endogenous PTEN knockdown reversed the growth inhibition effect of Tα1 in breast cancer cells. Further investigation revealed that PTEN up-regulation, which was induced by Tα1, can inhibit the activation of the PI3K/Akt/mTOR signaling pathway, leading to the growth inhibition of breast cancer cells. The addition of the synergy between Tα1 and the inhibition of PI3K/Akt/mTOR activation could strongly block cell viability in PTEN down-regulated breast cancer cells. PTEN-overexpressing cells not only up-regulated Bax and cleaved caspase-3/9 and PARP expression but also down-regulated Bcl-2 compared to the treatment with Tα1 alone. Together these findings suggest that PTEN mediates Tα1-induced apoptosis through the mitochondrial death cascade and inhibition of the PI3K/Akt/mTOR signaling pathway in breast cancer cells.

Thymosin α1 promotes the activation of myeloid-derived suppressor cells in a Lewis lung cancer model by upregulating Arginase 1

Thymosin α1 (Tα1) has been tested for cancer therapy for several years, in most cases, the anti-tumor effect of Tα1 was limited, especially when Tα1 was used as a single agent. The role of Tα1 in cancer treatment and the regulatory mechanisms by which Ta1 takes effects are not yet completely understood. Using a Lewis lung caner model, here we report that Tα1 used alone elevated CD8(+) T cells, but failed to inhibit tumor growth. Furthermore, immunosuppressive myeloid-derived suppressor cells (MDSCs) showed heightened Arginase 1 production in response to Tα1 treatment, which led to stronger suppression of anti-tumor immunity. In addition, the upregulation of ARG1 was dependent on TLRs/MyD88 signaling, blocking MyD88 signaling abrogated the enhanced ARG1 expression and restored the anti-tumor efficacy of Tα1. This study provides the first demonstration that Tα1 treatment activates but not expands MDSCs via MyD88 signaling, which indicates better immunotherapeutic strategy of Tα1 against cancer.

Prothymosin alpha: a ubiquitous polypeptide with potential use in cancer diagnosis and therapy

The thymus is a central lymphoid organ with crucial role in generating T cells and maintaining homeostasis of the immune system. More than 30 peptides, initially referred to as "thymic hormones," are produced by this gland. Although the majority of them have not been proven to be thymus-specific, thymic peptides comprise an effective group of regulators, mediating important immune functions. Thymosin fraction five (TFV) was the first thymic extract shown to stimulate lymphocyte proliferation and differentiation. Subsequent fractionation of TFV led to the isolation and characterization of a series of immunoactive peptides/polypeptides, members of the thymosin family. Extensive research on prothymosin α (proTα) and thymosin α1 (Tα1) showed that they are of clinical significance and potential medical use. They may serve as molecular markers for cancer prognosis and/or as therapeutic agents for treating immunodeficiencies, autoimmune diseases and malignancies. Although the molecular mechanisms underlying their effect are yet not fully elucidated, proTα and Tα1 could be considered as candidates for cancer immunotherapy. In this review, we will focus in principle on the eventual clinical utility of proTα, both as a tumor biomarker and in triggering anticancer immune responses. Considering the experience acquired via the use of Tα1 to treat cancer patients, we will also discuss potential approaches for the future introduction of proTα into the clinical setting.

Thymic peptides for treatment of cancer patients

BACKGROUND

Purified thymus extracts (pTE) and synthetic thymic peptides (sTP) are thought to enhance the immune system of cancer patients in order to fight the growth of tumour cells and to resist infections due to immunosuppression induced by the disease and antineoplastic therapy.

OBJECTIVES

To evaluate the effectiveness of pTE and sTP for the management of cancer.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2010, Issue 3), MEDLINE, EMBASE, AMED, BIOETHICSLINE, BIOSIS, CATLINE, CISCOM, HEALTHSTAR, HTA, SOMED and LILACS (to February 2010).

SELECTION CRITERIA

Randomised trials of pTE or sTP in addition to chemotherapy or radiotherapy, or both, compared to the same regimen with placebo or no additional treatment in adult cancer patients.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from published trials. We derived odds ratios (OR) from overall survival (OS) and disease-free survival (DFS) rates, tumour response (TR) rates, and rates of adverse effects (AE) related to antineoplastic treatments. We used a random-effects model for meta-analysis.

MAIN RESULTS

We identified 26 trials (2736 patients). Twenty trials investigated pTE (thymostimulin or thymosin fraction 5) and six trials investigated sTP (thymopentin or thymosin α(1)). Twenty-one trials reported results for OS, six for DFS, 14 for TR, nine for AE and 10  for safety of pTE and sTP. Addition of pTE conferred no benefit on OS (RR 1.00, 95% CI 0.79 to 1.25); DFS (RR 0.97, 95% CI 0.82 to 1.16); or TR (RR 1.07, 95% CI 0.92 to 1.25). Heterogeneity was moderate to high for all these outcomes. For thymosin α(1) the pooled RR for OS was 1.21 (95% CI 0.94 to 1.56, P = 0.14), with low heterogeneity; and 3.37 (95% CI 0.66 to 17.30, P = 0.15) for DFS, with moderate heterogeneity. The pTE reduced the risk of severe infectious complications (RR 0.54, 95% CI 0.38 to 0.78, P = 0.0008; I² = 0%). The RR for severe neutropenia in patients treated with thymostimulin was 0.55 (95% CI 0.25 to 1.23,  P = 0.15). Tolerability of pTE and sTP was good. Most of the trials had at least a moderate risk of bias.

AUTHORS' CONCLUSIONS

Overall, we found neither evidence that the addition of pTE to antineoplastic treatment reduced the risk of death or disease progression nor that it improved the rate of tumour responses to antineoplastic treatment. For thymosin α(1), there was a trend for a reduced risk of dying and of improved DFS. There was preliminary evidence that pTE lowered the risk of severe infectious complications in patients undergoing chemotherapy or radiotherapy.

Thymosin alpha 1: biological activities, applications and genetic engineering production

Thymosin alpha 1 (Tα1), a 28-amino acid peptide, was first described and characterized from calf thymuses in 1977. This peptide can enhance T-cell, dendritic cell (DC) and antibody responses, modulate cytokines and chemokines production and block steroid-induced apoptosis of thymocytes. Due to its pleiotropic biological activities, Tα1 has gained increasing interest in recent years and has been used for the treatment of various diseases in clinic. Accordingly, there is an increasing need for the production of this peptide. So far, Tα1 used in clinic is synthesized using solid phase peptide synthesis. Here, we summarize the genetic engineering methods to produce Tα1 using prokaryotic or eukaryotic expression systems. The effectiveness of these biological products in increasing the secretion of cytokines and in promoting lymphocyte proliferation were investigated in vitro studies. This opens the possibility for biotechnological production of Tα1 for the research and clinical applications.

Thymostimulin versus placebo for palliative treatment of locally advanced or metastasised hepatocellular carcinoma: a phase III clinical trial

Background

Thymostimulin is a thymic peptide fraction with immune-mediated cytotoxicity against hepatocellular carcinoma (HCC) in vitro and palliative efficacy in advanced HCC in two independent phase II trials. The aim of this study was to assess the efficacy of thymostimulin in a phase III trial.

Methods

The study was designed as a prospective randomised, placebo-controlled, double-blind, multicenter clinical phase III trial. Between 10/2002 and 03/2005, 135 patients with locally advanced or metastasised HCC (Karnofsky ≥60%/Child-Pugh ≤ 12) were randomised to receive thymostimulin 75 mg s.c. 5×/week or placebo stratified according to liver function. Primary endpoint was twelve-month survival, secondary endpoints overall survival (OS), time to progression (TTP), tumor response, safety and quality of life. A subgroup analysis according to liver function, KPS and tumor stage (Okuda, CLIP and BCLC) formed part of the protocol.

Results

Twelve-month survival was 28% [95%CI 17-41; treatment] and 32% [95%CI 19-44; control] with no significant differences in median OS (5.0 [95% CI 3.7-6.3] vs. 5.2 [95% CI 3.5-6.9] months; p = 0.87, HR = 1.04 [95% CI 0.7-1.6]) or TTP (5.3 [95%CI 2.0-8.6] vs. 2.9 [95%CI 2.6-3.1] months; p = 0.60, HR = 1.13 [95% CI 0.7-1.8]). Adjustment for liver function, Karnofsky status or tumor stage did not affect results. While quality of life was similar in both groups, fewer patients on thymostimulin suffered from accumulating ascites and renal failure.

Conclusions

In our phase III trial, we found no evidence of any benefit to thymostimulin in the treatment of advanced HCC and there is therefore no justification for its use as single-agent treatment. The effect of thymostimulin on hepato-renal function requires further confirmation.

Trial Registration

Current Controlled Trials ISRCTN64487365.

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.

Surgical treatment of hepatocellular carcinoma: expert consensus statement

As the number of effective treatment options has increased, the management of patients with hepatocellular carcinoma has become complex. The most appropriate therapy depends largely on the functional status of the underlying liver. In patients with advanced cirrhosis and tumor extent within the Milan criteria, liver transplantation is clearly the best option, as this therapy treats the cancer along with the underlying hepatic parenchymal disease. As the results of transplantation has become established in patients with limited disease, investigation has increasingly focused on downstaging patients with disease outside of Milan criteria and defining the upper limits of transplantable tumors. In patients with well preserved hepatic function, liver resection is the most appropriate and effective treatment. Hepatic resection is not as constrained by tumor extent and location to the same degree as transplantation and ablative therapies. Some patients who recur after resection may still be eligible for transplantation. Ablative therapies, particularly percutaneous radiofrequency ablation and transarterial chemoembolization have been used primarily to treat patients with low volume irresectable tumors. Whether ablation of small tumors provides long term disease control that is comparable to resection remains unclear.