Efficacy and safety of fexapotide triflutate in outpatient medical treatment of male lower urinary tract symptoms associated with benign prostatic hyperplasia

Fexapotide triflutate vs oral pharmacotherapy as initial therapy for moderate-to-severe benign prostate hyperplasia patients: a cost-effectiveness analysis

BACKGROUND

To assess the price range in which fexapotide triflutate (FT), a novel injectable, is cost-effective relative to current oral pharmacotherapy (5 α-reductase inhibitor, α-blocker, 5 α-reductase inhibitor and α-blocker combination therapy) as initial therapy followed by surgery for moderate-to-severe benign prostate hyperplasia patients with lower urinary tract symptoms (BPH-LUTS).

METHODS

We developed a microsimulation decision-analytic model to track the progression of BPH-LUTS and associated costs and quality-adjusted life years in the target population. The cost-effectiveness analysis was performed from Medicare's perspective with a time horizon of 4 years using 2019 US dollars for all costs. The microsimulation model considered treatment patterns associated with nonadherence to oral medication and progression to surgery. Model parameters were estimated from large randomized controlled trials, literature and expert opinion. For each initial treatment option, simulations were performed with 1000 iterations, with 1000 patients per iteration.

RESULTS

Three upfront oral pharmacotherapy options are close in cost-effectiveness, with combination therapy being the most cost-effective option. Relative to upfront oral pharmacotherapy options, FT slightly increases quality-adjusted life years (QALY) per patient (1.870 (95% CI, 1.868 to 1.872) vs. 1.957 (95% CI, 1.955 to 1.959) QALYs). Under the willingness-to-pay (WTP) threshold of $150,000 per QALY, at price per injection of $14,000, FT is about as cost-effective as upfront oral pharmacotherapy options with net monetary benefit (NMB) $279,168.54. Under the WTP threshold of $50,000 per QALY, at price per injection of $5,000, FT is about as cost-effective as upfront oral pharmacotherapy options with NMB $92,135.18. In an alternative 10-year time horizon scenario, FT price per injection at $11,000 and $4,500 makes FT as cost-effective as oral pharmacotherapies. One-way sensitivity analysis showed this result is most sensitive to upfront therapy prices, FT efficacy and initial IPSS. At price per injections of $5,000, $10,000 and $15,000, the probability that FT is either cost-effective or dominant compared to upfront oral pharmacotherapy options using a WTP threshold of $150,000 per QALY is 100%, 93% and 40%, respectively.

CONCLUSIONS

Compared to upfront oral pharmacotherapy options, FT would be cost-effective at a price per injection below $14,000, assuming a WTP threshold of $150,000 per QALY.

Prospective evaluation of fexapotide triflutate injection treatment of Grade Group 1 prostate cancer: 4-year results

Purpose

This study was undertaken to determine the safety and efficacy of fexapotide triflutate (FT) 2.5 mg and 15 mg for the treatment of Grade Group 1 prostate cancer.

Methods

Prospective randomized transrectal intraprostatic single injection FT 2.5 mg (n = 49), FT 15 mg (n = 48) and control active surveillance (AS) (n = 49) groups were compared in 146 patients at 28 U.S. sites, with elective AS crossover (n = 18) to FT after first follow-up biopsy at 45 days. Patients were followed for 5 years including biopsies (baseline, 45 days, and 18, 36, and 54 months thereafter), and urological evaluations with PSA every 6 months. Patients with Gleason grade increase or who elected surgical or radiotherapeutic intervention exited the study and were cumulatively included in the data analysis. Percentage of normal biopsies in baseline focus quadrant, tumor grades, and volumes; and outcomes including Gleason grade in entire prostate as well as treated prostate lobe, interventions associated with Gleason grade increase and total incidence of interventions were assessed.

Results

Significantly improved long-term clinical outcomes were found after 4-year follow-up, with percentages of patients progressing to interventions with and without Gleason grade increase significantly reduced by FT single treatment. Results in the FT 15-mg group were superior to the FT 2.5-mg dose group. There were no drug-related serious adverse events (SAEs).

Conclusions

FT showed statistically significant long-term efficacy in the treatment of Grade Group 1 patients regarding clinical and pathological progression. FT 15 mg showed superior results to FT 2.5 mg. There were no drug-related SAEs; FT injection was well tolerated.

Fexapotide Triflutate Induces Selective Prostate Glandular Pharmaco-Ablation in the Rat

Introduction

A clinical challenge for interventional prostate treatments for localized prostate cancer has been to elicit cancer tissue eradication which can avoid undesirable toxicities and irreparable damage to adjacent structures. Fexapotide triflutate (FT) has been shown in human clinical trials to be a well-tolerated pharmaco-ablative agent with therapeutic benefit in patients with prostate enlargement and low-grade prostate cancer.

Methods

Studies were undertaken in vitro and in the normal male rat to characterize and quantify selective ablation of prostate glandular cells exposed to fexapotide triflutate (FT) injections. N=371 2-month-old Sprague Dawley rats received direct intraprostatic injections under ether anesthesia with laparotomy (n=268 given 0.3 mL FT 0.1–2.0 mg/mL at varied schedules, and n=103 controls), and were sacrificed at intervals of 24 hr-12 months, with measurements of prostate volume, assessments of apoptosis, prostatic nerve structures, connective tissue stroma, and vasculature. In vitro prostate cell lines treated with FT were studied by electron microscopy and RNA quantification.

Results

Evidence shows that FT leads to prostate glandular cell loss not found in controls, by apoptosis within 24–72 hrs that is highly selective for achieving near-total loss of glandular epithelium at 6 to 12 months, without any adverse microscopic effects to adjacent periprostatic nerves, vascular elements, and stroma.

Conclusion

Histological studies in the rat demonstrate that FT ablative effect is selective for prostate glandular epithelium, sparing adjacent tissues and structures in the prostate including nerves, vasculature, and stroma.