Serlopitant for the treatment of chronic pruritus: Results of a randomized, multicenter, placebo-controlled phase 2 clinical trial.

BACKGROUND: The substance P/neurokinin 1 receptor pathway is critical in chronic pruritus; anecdotal evidence suggests that antagonism of this pathway can reduce chronic itch. OBJECTIVE: To assess the safety and efficacy of the substance P/neurokinin 1 receptor antagonist serlopitant in treating chronic pruritus. METHODS: Eligible patients with severe chronic pruritus who were refractory to antihistamines or topical steroids were randomized to serlopitant, 0.25, 1, or 5 mg, or to placebo, administered once daily for 6 weeks as monotherapy or with midpotency steroids and emollients. The primary efficacy end point was percentage change in visual analog scale pruritus score from baseline. RESULTS: Serlopitant treatment resulted in a dose-dependent decrease in pruritus. The mean percentage decreases from baseline visual analog scale pruritus scores were statistically significantly larger with the 1- and 5-mg doses of serlopitant (P = .022 and P = .013, respectively) than with placebo at week 6. No significant safety or tolerability differences were detected among the groups. LIMITATIONS: The sample size was insufficient for subgroup analyses of the efficacy of serlopitant for chronic pruritus on the basis of underlying conditions. CONCLUSIONS: Serlopitant, 1 mg and 5 mg daily, was associated with a statistically significant reduction in chronic pruritus and was well tolerated (NCT01951274).

Preclinical development and clinical translation of a PSMA-targeted docetaxel nanoparticle with a differentiated pharmacological profile.

We describe the development and clinical translation of a targeted polymeric nanoparticle (TNP) containing the chemotherapeutic docetaxel (DTXL) for the treatment of patients with solid tumors. DTXL-TNP is targeted to prostate-specific membrane antigen, a clinically validated tumor antigen expressed on prostate cancer cells and on the neovasculature of most nonprostate solid tumors. DTXL-TNP was developed from a combinatorial library of more than 100 TNP formulations varying with respect to particle size, targeting ligand density, surface hydrophilicity, drug loading, and drug release properties. Pharmacokinetic and tissue distribution studies in rats showed that the NPs had a blood circulation half-life of about 20 hours and minimal liver accumulation. In tumor-bearing mice, DTXL-TNP exhibited markedly enhanced tumor accumulation at 12 hours and prolonged tumor growth suppression compared to a solvent-based DTXL formulation (sb-DTXL). In tumor-bearing mice, rats, and nonhuman primates, DTXL-TNP displayed pharmacokinetic characteristics consistent with prolonged circulation of NPs in the vascular compartment and controlled release of DTXL, with total DTXL plasma concentrations remaining at least 100-fold higher than sb-DTXL for more than 24 hours. Finally, initial clinical data in patients with advanced solid tumors indicated that DTXL-TNP displays a pharmacological profile differentiated from sb-DTXL, including pharmacokinetics characteristics consistent with preclinical data and cases of tumor shrinkage at doses below the sb-DTXL dose typically used in the clinic.

A phase I study of SPI-077 (Stealth liposomal cisplatin) concurrent with radiation therapy for locally advanced head and neck cancer.

BACKGROUND: Liposomal cisplatin preparations have two potential advantages over the free drug when combined with radiation therapy (RT): 1) selective tumor localization, improving the therapeutic ratio, and 2) prolonged half-life, allowing more radiosensitization. We performed a Phase I study of Stealth liposomal cisplatin (SPI-077) concurrent with RT for head and neck squamous cell carcinoma (HNSCC). METHODS: Patients with Stage IVa/b HNSCC were treated with SPI-077, given intravenously twice two weeks apart, concurrent with RT (60-72 Gy in 6-7 weeks). The SPI-077 dose was escalated in standard phase I design. RESULTS: Twenty patients received 38 doses of SPI-077, escalated from 20-200 mg/m2 in six dose levels. Two of these patients received one dose because of reversible Grade 3 liver toxicity or rash. Three patients had a Grade 1, and one had a Grade 2 infusion reaction. Four patients had transiently elevated transaminases: Grade I (n = 1), Grade 2 (n = 1), and Grade 3 (n = 2). Grade 3 neutropenia occurred in one patient. There was no ototoxicity, neurotoxicity, or nephrotoxicity. In-field radiation skin and mucosal toxicities did not appear to be intensified. Ten of 17 patients (59%) finishing treatment achieved initial complete response. CONCLUSIONS: Systemic and in-field radiation toxicities of SPI-077 were minimal. Infusion reactions were minimized with a slower and more dilute initial infusion. Further dose escalation was stopped in the absence of dose-limiting toxicity to address the reformulation of the liposomally bound cisplatin. Nonetheless, this study shows that high doses of SPI-077 can be given safely. The potentially beneficial therapeutic ratio suggests that liposomal radiosensitizer preparations warrant further investigation.