Systematic Review of Gossypol/AT-101 in Cancer Clinical Trials

• Published in: Pharmaceuticals (Basel, Switzerland) Vol. 15; no. 2; p. 144
• Main Authors: Renner, Olga, Mayer, Mascha, Leischner, Christian, Burkard, Markus, Berger, Alexander, Lauer, Ulrich M, Venturelli, Sascha, Bischoff, Stephan C
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 26.01.2022; MDPI
• Subjects: Apoptosis; AT-101; cancer; Cancer therapies; Cell cycle; Chemotherapy; clinical trial; Clinical trials; Disease; Growth factors; Kinases; Medical prognosis; oncologic patients; oral gossypol; Prostate cancer; Proteins; Radiation therapy; Seeds; Systematic Review; Toxicity; clinical trial; cancer; oral gossypol; oncologic patients; AT-101
• ISSN: 1424-8247; 1424-8247
• DOI: 10.3390/ph15020144

The potential of gossypol and of its R-(-)-enantiomer (R-(-)-gossypol acetic acid, AT-101), has been evaluated for treatment of cancer as an independent agent and in combination with standard chemo-radiation-therapies, respectively. This review assesses the evidence for safety and clinical effectiveness of oral gossypol/AT-101 in treating various types of cancer. The databases PubMed, MEDLINE, Cochrane, and ClinicalTrials.gov were examined. Phase I and II trials as well as single arm and randomized trials were included in this review. Results were screened to determine if they met inclusion criteria and then summarized using a narrative approach. A total of 17 trials involving 759 patients met the inclusion criteria. Overall, orally applied gossypol/AT-101 at low doses (30 mg daily or lower) was determined as well tolerable either as monotherapy or in combination with chemo-radiation. Adverse events should be strictly monitored and were successfully managed by dose-reduction or treating symptoms. There are four randomized trials, two performed in patients with advanced non-small cell lung cancer, one in subjects with head and neck cancer, and one in patients with metastatic castration-resistant prostate cancer. Thereby, standard chemotherapy (either docetaxel (two trials) or docetaxel plus cisplatin or docetaxel plus prednisone) was tested with and without AT-101. Within these trials, a potential benefit was observed in high-risk patients or in some patients with prolongation in progression-free survival or in overall survival. Strikingly, the most recent clinical trial combined low dose AT-101 with docetaxel, fluorouracil, and radiation, achieving complete responses in 11 of 13 patients with gastroesophageal carcinoma (median duration of 12 months) and a median progression-free survival of 52 months. The promising results shown in subsets of patients supports the need of further specification of AT-101 sensitive cancers as well as for the establishment of effective AT-101-based therapy. In addition, the lowest recommended dose of gossypol and its precise toxicity profile need to be confirmed in further studies. Randomized placebo-controlled trials should be performed to validate these data in large cohorts.