Thymic peptides for treatment of cancer patients

Cochrane Database Syst Rev. 2011 Feb 16;2011(2):CD003993. doi: 10.1002/14651858.CD003993.pub3.


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.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Adjuvants, Immunologic / adverse effects
  • Adjuvants, Immunologic / therapeutic use*
  • Adult
  • Disease-Free Survival
  • Female
  • Humans
  • Immune System / drug effects*
  • Immunocompromised Host
  • Male
  • Neoplasms / drug therapy
  • Neoplasms / immunology*
  • Peptides / adverse effects
  • Peptides / therapeutic use*
  • Thymalfasin
  • Thymopentin / therapeutic use
  • Thymosin / analogs & derivatives
  • Thymosin / therapeutic use
  • Thymus Extracts / adverse effects
  • Thymus Extracts / therapeutic use*
  • Thymus Gland / chemistry*


  • Adjuvants, Immunologic
  • Peptides
  • Thymus Extracts
  • thymostimulin
  • Thymosin
  • Thymopentin
  • Thymalfasin