Phase 1/2 study of topical submicron particle paclitaxel for cutaneous metastases of breast cancer.

PURPOSE: This Phase 1/2 study evaluated safety and efficacy of a topical submicron particle paclitaxel (SPP) in an anhydrous ointment base (SOR007), primarily in breast cancer patients with cutaneous metastases (CM). METHODS: One of three concentrations of SOR007 SPP (0.15%, 1.0%, or 2.0%) was applied twice daily over an area of 50 cm2 under a 3 + 3 phase 1 design for up to 28 days, with the option for expansion to an additional 28 days at the highest dose under a Phase 2a once safety was established. Efficacy was analyzed by lesion measurements and photographs to determine overall response rate (ORR), complete response (CR), and progression free survival by day 28 or 56. RESULTS: Twenty-three subjects were enrolled, 21 with cutaneous metastases of breast cancer (CMOBC). Four subjects received SOR007 0.15% for a median of 28 days (range = 17-29), three at a dose of 1.0% for a median of 28 days (range = 6-29), and sixteen at 2.0% for a median of  55 days (range = 6-60). All doses were well tolerated, and 19 subjects were evaluable for efficacy. At day 28 across all dose levels, 16% (95% CI 3.4 to 39.6%) of subjects achieved an ORR and another 63% (95% CI 34.9-96.8%) had stable disease (SD). The proportion of patients being progression free at 28 days across all treatments was 79% (95 CI 54-94%). CONCLUSION: Application of SOR007 0.15%, 1.0%, and 2.0% to CM was safe and well tolerated with some reduction in lesion pain, and minimal systemic absorption of paclitaxel. Lesion stabilization was observed in most subjects over the study period. A randomized, placebo-controlled trial to confirm these findings is warranted. GOV IDENTIFIER: NCT03101358.

Phase 1/2 Trial Results of a Large Surface Area Microparticle Docetaxel for the Treatment of High-Risk Nonmuscle-Invasive Bladder Cancer.

PURPOSE: We investigated the safety, preliminary efficacy, and immune effects of large surface area microparticle docetaxel (LSAM-DTX) administered by direct injection after transurethral resection of bladder tumor (TURBT), and by intravesical instillation in high-risk nonmuscle-invasive bladder cancer. MATERIALS AND METHODS: The trial followed an open-label 3+3 dose escalation with additional enrollment at the high dose. After TURBT, subjects received direct injection LSAM-DTX into the resection site and intravesical LSAM-DTX, followed by 6-week induction and 3-week maintenance intravesical LSAM-DTX courses. Tumor recurrence was evaluated by cytology, cystoscopy, or biopsy. Pharmacokinetic analysis of blood and multiplex immunofluorescence of tumor microenvironment occurred pre- and post-LSAM-DTX. RESULTS: Nineteen subjects were enrolled, 14 with prior bacillus Calmette-Guérin exposure and 16 with ≥1 prior TURBT. Direct injection and intravesical LSAM-DTX were well tolerated. In the 3 lowest dose escalation cohorts the median recurrence-free survival was 5.4 months (10 patients, median followup 8.6 months). In the high-dose and expansion cohorts median recurrence-free survival was significantly increased (p <0.05, hazard ratio 0.29) to 12.2 months (9 patients, median followup 12.4 months). Systemic docetaxel exposure was negligible and increases in antitumor immune cells were found in the tumor microenvironment along with elevations in the PD-1, PD-L1 and CTLA-4 immune checkpoint inhibitor targets. CONCLUSIONS: Post-TURBT direct injection and intravesical LSAM-DTX were well tolerated and demonstrated clinical response for patients with high-risk nonmuscle-invasive bladder cancer. Favorable immune cell infiltration and checkpoint receptor increases following LSAM-DTX treatment warrants investigation alone as well as in combination with immune checkpoint inhibitor therapy.