Quality of Life is Improved in Breast Cancer Patients by Standardised Mistletoe Extract PS76A2 during Chemotherapy and Follow-up: A Randomised, Placebo-controlled, Double-blind, Multicentre Clinical Trial

Abstract

The objective of this randomised, multicentre, double-blind clinical trial was to investigate the impact of PS76A2, an aqueous mistletoe extract standardised to mistletoe lectins, on quality of life (QoL) in breast cancer patients. A total of 352 patients were randomly allocated to 2 groups receiving PS76A2 (15 ng mistletoe lectin/0.5 ml) or matching placebo twice weekly for 4 to 6 cycles of CMF (cyclophosphamide, methotrexate, fluorouracil) chemotherapy followed by 2 months follow-up. The primary efficacy end-point was the change from baseline of 3 FACT-G subscales (physical, emotional and functional well-being) during the fourth CMF cycle. Secondary measures included GLQ-8 (8 linear analogue self-assessment scales), Spitzer's uniscale and haematological variables. The main variables of safety analysis were adverse events, including injection site reactions and clinical laboratory tests. The results showed that physical, emotional and functional well-being improved upon PS76A2, but deteriorated following placebo. The treatment differences were statistically significant for the 3 subscales as well as for the summary score FACT-G, which was analysed as O'Brien's rank sum of its 3 subscales. The total score increased by 4.40±11.28, indicating a higher QoL after PS76A2, but decreased by 5.11±11.77 with placebo (p<0.0001). The GLQ-8 sum of 8 LASA scales was analysed as a summary score of GLQ-5 (sum of item nos. 1, 5, 6, 7, 8) and GLQ-3 (sum of item nos. 2, 3, 4). GLQ-5 characterises typical aspects of QoL, while GLQ-3 consists of 3 side-effects of CMF (feeling sick, numbness or pins and needles, loss of hair). GLQ-5 decreased by 42.9±125.0 upon PS76A2, indicating an improvement in QoL, but increased by 60.3±94.0 upon placebo (p<0.0001). GLQ-3 deteriorated in both groups (PS76A2: 13.9±52.4; placebo: 34.5±57.0), but the differences in favour of PS76A2 were, nevertheless, statistically significant (p=0.0007). The total score GLQ-8 improved by 28.9±154.6 after PS76A2 and deteriorated by 94.8±141.1 after placebo (p<0.0001). Spitzer's uniscale improved by 12.2±30.7 upon PS76A2 and deteriorated by 10.8±26.1 with placebo (p<0.0001). After follow-up without chemotherapy, a significant treatment difference in favour of PS76A2 was determined by means of FACT-G, GLQ-8 and Spitzer's uniscale. PS76A2 was well tolerated in this trial, with the exception of slight local reactions in 17.6% of the PS76A2 group. In conclusion, PS76A2 (15 ng mistletoe lectin/0.5 ml twice weekly) was shown to be safe and effective in improving QoL in breast cancer patients during chemotherapy and follow-up.