Interim data released from a phase 2 clinical trial suggest that oral administration of PectaSol-C Modified Citrus Pectin (P-MCP) can safely improve Prostate Specific Antigen (PSA) kinetics in men with biochemical relapsed prostate cancer (BRPC) and serial increases in PSA levels.
The findings are part of an interim analysis published in the Journal of Clinical Oncology. Final results will be published after completion of the 18-month study.
Among men, prostate cancer is the second most common cancer and the second leading cause of cancer-related death. The primary treatment for prostate cancer is surgery or radiation, but approximately 33% of patients will recur in the form of non-metastatic biochemically relapsed prostate cancer (BRPC-M0).
In these patients, PSA rises while scans are negative for metastasis. Currently, there is no standard therapy for BRPC-M0 with proven benefits, and surveys show that many prostate cancer patients use various complementary and alternative medicine modalities.
Prior studies have shown that P-MCP, derived from citrus fruit peels altered to improve absorption, inhibits carbohydrate mediated tumor growth, angiogenesis, and metastasis by antagonizing galectin-3 function.1
In this prospective, open-label study, men were enrolled with documented prostate cancer post local therapy and biochemical relapse, defined as linear progression of at least three PSA tests in at least 3 months. In addition, patients had negative bone scan and CT scan of the chest-abdomen-pelvis within two weeks prior to study initiation.
Men were excluded for conditions that may prevent compliance or completion of protocol, poorly controlled co-morbidities, hormonal therapy, or other therapy for PC in the previous three months.2
Participants were treated with PectaSol-C MCP 4.8 g three times daily (away from meals) for six months. Patients who tolerate therapy and do not progress clinically, biochemically (based on PSA), or radiologically at 6 months are treated for a subsequent 12 months.
Patient tolerability will be assessed by comparing the results of monthly self-assessment diaries with baseline assessments. The study plans to enroll 60 patients.
The researchers reported the first results of pre-planned interim analysis after six months and 35 enrolled patients. The median age was 74 years. Treatment of primary tumor consisted of surgery in 11% (n=4), radiation in 69% (n=24), and both in 20% (n=7). No patient had treatment-related toxicity of grade 3 or 4. One patient withdrew consent.
Of the 34 participants analyzed, 62% had a stabilization/decrease of PSA and negative scans at six months; they were entered into the second treatment phase. A stabilization or improvement (increase) of PSA doubling time was noted in 79% of patients; 8% had grade 1 toxicity.
Disease progression at 6 months occurred in 38%. Of those patients, 10 had progression based on PSA only, and three had progression based on PSA and scans.
Although final analysis is pending, the authors suggested that P-MCP therapy is safe and has a potential benefit on BRPC progression.
The final report will include blood serum analysis for galectin-3, C-reactive protein, and lipids. Blood samples will be drawn at baseline and at the end of 6 months.
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- Yan J and Katz A. Integr Cancer Ther. 2010 Jun;9(2):197-203.
- Keizman D, et al. J Clin Oncol. 2017 35:15_suppl, e16588-e16588.