Modified citrus pectin treatment showed durable efficacy and a good safety profile in treating non-metastatic biochemically relapsed prostate cancer in a phase 2 clinical trial.
Among patients treated for localized prostate cancer, 20–50% experience a biochemical relapse (BRPC-M0) within 10 years of treatment, with an optimal therapy remaining elusive. PectaSol-Modified Citrus Pectin (P-MCP), a commercially available food supplement, is an inhibitor of the galectin-3 protein involved in cancer pathogenesis.
In a phase II trial, P-MCP treatment for 6 months resulted in an improvement in prostate-specific antigen doubling time (PSADT) in 75% of BRPC-M0 patients. A study in the journal Nutrients has reported the long-term results of the trial after an additional 12 months of P-MCP therapy in patients without disease progression after the initial therapy.
Of the 46 patients who benefited from the initial 6 months of treatment, 39 were treated for an additional 12 months (a total of 18 months). The median age was 75 years.
Long-Term Efficacy Outcomes
- Primary Endpoint
Out of the 39 patients, 85% (n=33) demonstrated a decreased or stable PSA and/ or improvement (lengthening) in PSADT (54%, n=21), with negative scans (90%, n=35) compared to baseline. There was a significant improvement in the median PSADT compared to the baseline, from a median pre-treatment PSADT of 10.3 months to a median post-treatment PSADT of 43.5 months. These primary endpoint benefits were observed in all PSADT risk groups.
- Secondary Endpoints
After 18 months of therapy with P-MCP, all patients with a pre-treatment PSADT risk grouping of poor (<3 months) improved to an intermediate–good risk, and 77% of patients with a pre-treatment PSADT intermediate risk improved to the good risk category. Among patients with a pre-treatment PSADT in the good risk category, 91% retained their risk grouping, 87% of which showed improvement.
After 18 months of P-MCP therapy, the pre-treatment distribution of PSADT risk groupings improved, with the proportion of patients decreasing from 8% to 0% and from 33% to 13% in the poor risk and intermediate risk groups, respectively. The proportion of patients in the good risk group increased from 59% to 87%. There was a significant change in the median PSADT post-treatment versus baseline for those with a pre-treatment PSADT in the good risk category (45.9 vs. 14.7 months) and intermediate risk (22.75 vs. 5.1 months). Disease progression was observed in 18% of patients; 8% had PSA progression only, and 10% had both PSA and radiologic progression.
None of the patients experienced grade 3 or 4 toxicity. Grade 1 toxicity was noted in 30% of patients during the first 6 months of therapy and 23% during the next 12 months.
Keizman, D., Frenkel, M., Peer, A., Rosenbaum, E., Sarid, D., Leibovitch, I., Mano, R., Yossepowitch, O., Wolf, I., Geva, R., Margel, D., Rouvinov, K., Stern, A., Dresler, H., Kushnir, I., & Eliaz, I. (2023). Modified citrus pectin Treatment in Non-Metastatic Biochemically Relapsed Prostate Cancer: Long-Term results of a prospective Phase II study. Nutrients, 15(16), 3533. https://doi.org/10.3390/nu15163533