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.
Study Population
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.
Safety
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.
Source:
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
