The 2008 World Health Organization World Cancer Report describes global cancer incidence soaring with many patients living in countries that lack resources for cancer control. Alternative treatment strategies that can reduce the global disease burden at manageable costs must be developed. Polysaccharopeptide (PSP) is the bioactive agent from the mushroom
The 2008 World Health Organization World Cancer Report describes the global cancer incidence soaring, with 20 million new patients each year by 2020 [
The role of complementary and alternative medicine continues to evolve in the treatment regimen of cancer patients. Herbal medicines have predominantly been regarded for promoting wellness through the potentiation of immune functions. Beginning in the 1990s however, it has become increasingly clear that mushrooms and mushroom extracts have activities beyond that of the immune system. They have the potential to directly suppress tumorigenesis [
The mushroom
Randomized controlled trials investigating the efficacy of PSP in cancer patients report positive results for markers of immune function but lack clear evidence for antitumor activity and the ultimate clinically relevant outcome of increased survival [
Because of its high metastatic rate and vascular origin, canine hemangiosarcoma has significant model potential for investigations in antimetastatic therapies in general and antiangiogenic modalities in particular [
This pilot study was a randomized, double-blind, and multidose study of I’m-Yunity in dogs with a histopathologic diagnosis of splenic hemangiosarcoma. Dogs were recruited from a university-based tertiary care veterinary academic teaching hospital. A computer generated randomization sequence with 3 potential treatment groups (I’m-Yunity 25, 50, or 100 mg/kg/day) was generated at an off-site pharmacy. The randomization scheme was stratified according to the presence or absence of metastatic disease documented at the time of diagnosis. The sequence was concealed so that no members of the research team were aware of the group to which a dog would be allocated as it was evaluated in the screening process. Once screening was completed and a dog was considered eligible for inclusion in the study, a unique study number was assigned in sequence. The study number and body weight of each dog were then provided to the pharmacy. Pharmacy personnel matched the study number with their randomization sequence, formulated the appropriate treatment, and packaged capsules for distribution by the investigators. Capsules were formulated to appear identical. Thus, all study personnel and the owners of the dogs were unaware of the dose group to which each dog was assigned. Owners administered the capsules to their dogs daily as prescribed until the death of the dog. In-hospital evaluations of the dogs occurred at screening, baseline, and at monthly intervals until each dog’s death. Each dog underwent a full necropsy following its death.
I’m-Yunity (brand name) is an extract of
Amino acids in the protein portion of I’m-Yunity PSP (polysaccharopeptide).
Amino acid | Content (%) |
---|---|
Aspartic acid | 4.0 |
Threonine | 2.3 |
Serine | 3.2 |
Glutamic acid | 5.8 |
Proline | 1.0 |
Glycine | 2.6 |
Alanine | 2.6 |
Cysteine | 0.9 |
Valine | 1.8 |
Methionine | 0.4 |
Isoleucine | 2.2 |
Leucine | 2.4 |
Tyrosine | 1.5 |
Phenylalanine | 1.5 |
Tryptophan | 1.7 |
Lysine | 2.3 |
Histidine | 0.7 |
Arginine | 1.8 |
Dogs were screened for enrollment from September 2008 through November 2009 following Institutional Animal Care and Use Committee approval by the University and written informed consent by the owners of the dogs. Inclusion criteria were histopathologic diagnosis of splenic hemangiosarcoma and life expectancy ≥4 weeks. Only dogs whose owners opted not to pursue chemotherapy following splenectomy were eligible for enrollment.
All dogs were evaluated at baseline to ensure that they were stable in their general condition. Hematological and biochemical tests (complete blood count, electrolytes, liver and renal function), 3-view digital thoracic radiographs, and contrast enhanced harmonic abdominal ultrasound [
Descriptive statistics were calculated. Continuous data were expressed as mean and SD, unless not normally distributed, in which case median values and ranges were reported. Categorical data were expressed as frequencies. Because of the nonnormality of the data, the Kruskal Wallis test was used to evaluate the changes that occurred in complete blood count and serum biochemistry parameters within each dose group and between dose groups over time. The Mann Whitney test was used to compare the median days to progression of abdominal metastases between the high-(100 mg/kg/day) and low-(25 mg/kg/day) dose groups. Median survival times were determined by the use of the Kaplan-Meier product limit method and log rank analysis was used to compare survival curves amongst dose groups.
The baseline characteristics of 15 dogs with splenic hemangiosarcoma enrolled in the study were equally distributed amongst the three treatment groups (25 mg/kg/day, 50 mg/kg/day, or 100 mg/kg/day) via randomization and are presented in Table
Baseline characteristics of 15 dogs diagnosed with splenic hemangiosarcoma randomized to one of three doses of I’m-Yunity.
I'm-Yunity (polysaccharopeptide) | |||
---|---|---|---|
25 mg/kg/day | 50 mg/kg/day | 100 mg/kg/day | |
( |
( |
( |
|
Breed | 1 mixed breed (20%) | 2 mixed breed (40%) | 2 mixed breed (40%) |
|
|
| |
Age (years) | 9.0 ± 1.9 | 9.6 ± 2.7 | 8.6 ± 1.1 |
Weight (kg) | 34.0 ± 7.0 | 28.2 ± 4.8 | 30.0 ± 12.8 |
Sex | 1 female (20%) | 2 female (40%) | 1 female (20%) |
4 male (80%) | 3 male (60%) | 4 male (80%) | |
Metastatic disease present at enrollment | 2 no (40%) | 2 no (40%) | 2 no (40%) |
3 yes (60%) | 3 yes (60%) | 3 yes (60%) | |
Time from diagnosis to study enrollment (days) | 16 ± 9 | 23 ± 10 | 20 ± 8 |
Median and range blood chemistry values for 15 dogs with hemangiosarcoma treated with 25, 50, or 100 mg/kg/day I'm-Yunity (polysaccharopeptide).
Normal values | 25 mg/kg/day | 50 mg/kg/day | 100 mg/kg/dy | ||||||
---|---|---|---|---|---|---|---|---|---|
Baseline |
Week 3 |
Week 7 |
Baseline |
Week 3 |
Week 7 |
Baseline |
Week 3 |
Week 7 |
|
Glucose |
79 |
88 |
91 |
101 |
100 |
100 |
87 |
96 |
91 |
BUN |
17 |
25 |
27 |
18 |
19 |
19 |
25 |
27 |
26 |
Creatinine |
0.9 |
1.4 |
1.9 | 1.0 |
1.0 |
1.0 |
1.2 |
1.2 |
1.0 |
Calcium |
10.4 |
10.3 |
12.0 | 9.7 |
10.2 |
10.0 |
10.2 |
10.2 |
10.1 |
Sodium |
144 |
141 |
141 | 146 |
144 |
143 |
146 |
146 |
146 |
Potassium |
4.9 |
4.4 |
5.1 | 4.6 |
4.5 |
4.4 |
4.8 |
4.8 |
4.6 |
Total protein |
6.3 |
6.0 |
5.5 | 6.0 |
5.9 |
5.8 |
5.9 |
6.1 |
6.4 |
Albumen |
3.0 |
3.0 |
3.2 | 3.2 |
3.1 |
3.3 |
3.0 |
3.0 |
3.2 |
Globulin |
3.2 |
3.0 |
2.3 | 2.8 |
2.7 |
2.5 |
2.8 |
3.1 |
3.1 |
ALT |
32 |
46 |
32 |
60 |
49 |
89 |
59 |
62 |
36 |
SAP |
143 |
148 |
105 | 83 |
79 |
461 |
112 |
82 |
131 |
Total bilirubin 0.1–0.5 mg/dl | 0.1 |
0.2 |
0.5 | 0.3 |
0.1 |
0.3 |
0.1 |
0.2 |
0.2 |
Cholesterol |
260 |
300 |
343 | 247 |
233 |
242 |
220 |
260 |
332 |
Median and range complete blood count values for 15 dogs with hemangiosarcoma treated with 25, 50, or 100 mg/kg/day I'm-Yunity (polysaccharopeptide).
Normal values | 25 mg/kg/day | 50 mg/kg/day | 100 mg/kg/dy | ||||||
---|---|---|---|---|---|---|---|---|---|
Baseline |
Week 3 |
Week 7 |
Baseline |
Week 3 |
Week 7 |
Baseline |
Week 3 |
Week 7 |
|
Red blood cells |
5.3 |
4.3 |
4.3 | 5.8 |
6.0 |
4.2 |
5.2 |
5.7 |
5.4 |
Hemoglobin |
12.6 |
10.4 |
10.8 | 12.9 |
13.1 |
8.9 |
12.7 |
14.3 |
13.7 |
Hematocrit |
36.2 |
29.4 |
30.8 | 37.1 |
37.5 |
26.2 |
35.4 |
40.7 |
37.8 |
Platelets |
639 |
422 |
536 | 441 |
272 |
117 |
577 |
569 |
532 |
White blood cell |
10.2 |
7.7 |
9.3 | 8.2 |
10.6 |
12.4 |
9.7 |
11.0 |
9.9 |
Neutrophils |
6.7 |
5.6 |
7.9 | 6.5 |
7.7 |
10.8 |
6.5 |
9.2 |
7.4 |
Lymphocytes |
1.9 |
1.0 |
0.8 | 0.8 |
0.7 |
0.7 |
0.9 |
1.7 |
2.0 |
Monocytes |
0.7 |
0.5 |
0.4 | 0.6 |
0.7 |
0.7 |
0.5 |
0.4 |
0.5 |
Eosinophils |
0.7 |
0.4 |
0.2 | 0.3 |
0.5 |
0.1 |
0.4 |
0.5 |
0.3 |
The median time to development or progression of abdominal metastases was significantly delayed in dogs receiving 100 mg/kg/day I’m-Yunity (112 days; range 30 to 308 days) compared to dogs receiving 25 mg/kg/day (30 days; range 16 to 126 days;
Days to progression of abdominal metastases for 15 dogs diagnosed with splenic hemangiosarcoma randomized to one of three doses of I’m-Yunity (5 dogs in each dose group). * Denotes a statistically significant difference (
The Kaplan Meier survival curves for the three dose groups are presented in Figure
Kaplan Meier survival curves for 15 dogs diagnosed with splenic hemangiosarcoma randomized to one of three doses of I’m-Yunity (5 dogs in each dose group). “O” represents the shortest median survival time reported in the literature (19 days). “X” represents the longest median survival time reported in the literature (86 days).
The goal of this study was to collect pilot data on the potential effect of I’m-Yunity on the morbidity (progression of abdominal metastases) and mortality associated with a naturally occurring cancer in a large and complex species. The study was designed to collect outcome data so that a definitive proof-of-concept study could be appropriately powered, while also evaluating a range of potential doses. The goals of the study were met as expected; however, the magnitude of the positive outcomes and their relationship to dose was unexpected in such a small cohort, particularly in such an aggressive neoplastic disease.
Dogs with splenic hemangiosarcoma are often asymptomatic until the tumor ruptures causing the dog to collapse due to hemorrhagic/hypotensive shock. Many owners will opt for emergency surgical removal of the spleen to save the dog’s life through the crisis, despite the fact that the long-term prognosis for the dog could be very poor since 70% of dogs with splenic masses presenting with nontraumatic hemoabdomen do indeed have hemangiosarcoma as the underlying pathology [
Metastatic hemangiosarcoma throughout the omentum at necropsy of a dog with splenic hemangiosarcoma 6 months following splenectomy.
I’m-Yunity has demonstrated antitumor activities in tissue culture studies, based principally on data using flow cytometry. It causes cell cycle arrest and alterations in the expression of apoptogenic/antiapoptotic and extracellular signaling proteins, the net result being a reduction in proliferation and an increase in apoptosis [
PSP has been widely used as therapeutic adjuvant for cancer immunotherapy in China and Japan [
There could be several reasons for the lack of clear evidence of the clinically relevant antitumor effects in clinical trials, the first of which is, perhaps there are no such positive effects associated with PSP in cancer patients to be identified. The inability of preclinical findings to predict clinical efficacy is a concern throughout biomedical research and must be considered as a possible reason for the disconnect between preclinical and clinical data to date [
The use of animals as models to address preclinical study of cancer therapeutics has a long history, and important information has been acquired on new and innovative therapies. Most of these investigations have used inbred rodent models and laboratory-derived canine populations. Working with inbred populations in laboratory environments raises some degree of concern over the applicability of information as it relates to naturally occurring tumors in people. While the choice of companion dog model for this proof-of-concept pilot data collection is outside the traditional laboratory animal paradigm, it offers some interesting and useful advantages.
The degree of medical surveillance of the dog is second only to that in humans. The dog’s state of health is observed in intimate detail on a day-to-day basis and its ailments are attended by veterinary specialists using all of the diagnostic approaches of modern medicine [
It was not anticipated that such clear dose-dependent patterns in efficacy data would emerge or that any statistically significant dose-related information would be identified in such a small cohort. While it is necessary to now document more robust and statistically significant differences in an appropriately powered definitive placebo controlled study, it is encouraging that clear patterns and an obvious dose choice emerged from the pilot program. The median time to development or progression of abdominal metastases was significantly delayed in dogs receiving 100 mg/kg/day I’m-Yunity, which was documented on enhanced harmonic abdominal ultrasound. It was also reflected in the fact that while the majority of dogs never developed a normal hematocrit because of low grade bleeding episodes from abdominal metastases, four dogs did achieve a normal hematocrit during the course of the study and all four dogs were in the 100 mg/kg/day dose group. In addition, dogs in this dose group had the longest median survival times reported to date. The fact that these animals had not received adjuvant therapies such as chemotherapy in addition to the PSP, may have allowed the antitumor effects of PSP to be more readily realized. It is noteworthy that the median survival time for dogs in the 100 mg/kg/day treatment group (199 days) was longer than that which is reported for dogs receiving doxorubicin based chemotherapeutic protocols (141 to 179 days). Based on this data, one could hypothesize that PSP has the potential to have effects on survival similar to that which is seen with standard of care chemotherapy. Proving, in a biologically aggressive animal model, that PSP delivers antitumor and survival effects in a magnitude similar to that which is seen in standard chemotherapy could have significant implications for shifts in standard of care from current cytotoxic therapies to complementary compounds, such as PSP, that have little to no negative documented effects on normal cells. Most importantly, for those cancer patients throughout the world for whom advanced treatments and cytotoxic therapies are not accessible, CAM, such as PSP as a single agent, could offer benefits to survival and quality of life that are not yet imagined for those populations.
The authors thank Michael DiGregorio for technical support and Drs. Ana Caceres and Gabi Seiler for assistance with contrast harmonic ultrasound imaging. Dr. Cimino Brown was the PI on the study responsible for protocol development, protocol implementation, statistical analysis. and paper development. Dr. Reetz was responsible for determination of the progression of metastases endpoint through performance and evaluation of contrast harmonic ultrasound imaging and paper review. The project was funded through a grant from Chinese Medicine Holdings, LTD. The authors have no conflict of interests.