Leuprolide Acetate Formulations Research Articles

Intranasal Delivery of Leuprolide Acetate Chitosan Nanoparticles for Treatment of Alzheimer’s Disease

Background: Alzheimer’s is one of the primary causes and the most prevalent form of age-related dementia worldwide. There is an urgent surge to find an effective treatment for AD due to its social implications on society. Aim: Present research work aims to develop Chitosan nanoparticles of leuprolide acetate for the treatment of Alzheimer’s disease by delivery through the intranasal route. Methods: Chitosan nanoparticles encapsulating leuprolide acetate were prepared using the ionic ge-lation method and optimized using a central composite design. The optimized nanoparticles were evaluated by DSC study, TEM analysis, release study of the drug in vitro and ex vivo, histopatholo-gy study, and accelerated stability study, In vivo kinetic and dynamic study. Results: The optimized formulation exhibited particle size of 254.3 ± 10.7 nm, % EE of 85.6 ± 0.8 %, and zeta potential of +18.0 ± 0.2 mv. The release of drug from optimized nanoparticles in vitro was in a sustained manner, with only 75.7 % drug released at 48 hours. Higher permeation of the drug from nanoparticles (Papp =5.44 ± 0.34 x 104) was observed in the diffusion study ex vivo. Sheep nasal toxicity and accelerated stability study proved the intranasal safety and stability of the developed formulation. The in vivo drug uptake study indicated a greater brain drug concentration from chitosan nanoparticles than from plain drug solution. The anti-Alzheimer potential was also evident from behavioural studies and histopathology study of rat brain. Conclusion: Thus, the chitosan nanoparticulate formulation of leuprolide acetate was found to have great potential for Alzheimer’s disease management.

Abstract OT3-04-01: A Phase 3 study evaluating ovarian suppression following three-month leuprolide acetate in combination with endocrine therapy in premenopausal subjects with HR+, HER2-negative breast cancer (OVELIA)

Abstract Background: In US clinical practice, GnRH agonists are widely used to suppress ovarian function in pre/perimenopausal patients with breast cancer that is moderate-to high-risk for recurrence. Despite extensive use of leuprolide acetate (LA) for ovarian suppression, regulatory approval for this indication has not been established in the US. Additionally, existing three month formulations may not reliably provide ovarian suppression, as demonstrated by escapes in estradiol (E2). An extended-release LA product with a 3-month dosing period specifically developed for ovarian suppression in patients with breast cancer could fill this unmet need. TOL2506 is a 3-month, extended-release formulation of 30 mg of LA. This combination of active drug and in situ polymeric extended release technology is expected to deliver higher exposure to drug than the currently available 3-month (22.5 mg) formulations of LA marketed for advanced prostate cancer and potentially reduce escapes in E2 over the dosing period. Methods: TOL2506A (OVELIA) is a phase 3, single arm, open-label study evaluating the effectiveness of TOL2506 to suppress ovarian function in premenopausal women with HR+, HER2-negative breast cancer. Approximately 250 subjects will be enrolled targeting 220 evaluable subjects, with 30% aged 40 years or younger. Subjects must be premenopausal women, age 18-49 (inclusive), with a diagnosis of Stage I, II, or III HR+, HER2-negative breast cancer (ER>1% and/or, PR>1%, HER2-negative per ASCO CAP guidelines), who are candidates for ovarian suppression with endocrine therapy. For subjects receiving chemotherapy, premenopausal status will be determined prior to initiating chemotherapy. Male subjects with HR+, HER2-negative breast cancer may also be eligible, but will be evaluated for safety analyses only. Eligible subjects will enter the 48 week Treatment Period in 2 groups: those receiving tamoxifen concurrently with TOL2506 or those who initiate therapy with an aromatase inhibitor (AI; letrozole, anastrozole, or exemestane) beginning 6 weeks after the first administration of TOL2506, if E2 < 20 pg/mL has been achieved. After Week 12, subjects will be allowed to switch from receiving an AI to receiving tamoxifen or from tamoxifen to AI at the Investigator’s discretion. Subjects will receive 4 doses of TOL2506 every 12 weeks over the 48 week study duration. The primary endpoint to be evaluated is ovarian suppression, defined as ≥ 90% of subjects with LH levels < 4 IU/L at Week 6. Secondary endpoints include suppression of LH, E2 (< 20 pg/mL for tamoxifen cohort and < 2.72 pg/mL for AI cohort) and absence of menses at weeks 6, 12, 24, 36, and 48. NCT04906395 Citation Format: Ryan Turncliff, Erika Hamilton, Kerlin Lynch, Stuart N. Atkinson. A Phase 3 study evaluating ovarian suppression following three-month leuprolide acetate in combination with endocrine therapy in premenopausal subjects with HR+, HER2-negative breast cancer (OVELIA) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT3-04-01.

Clinical development of the GnRH agonist leuprolide acetate depot

Leuprolide acetate is the first GnRH agonist that entered clinical development after the discovery of the native GnRH. Several long-acting depot formulations of leuprolide acetate (ranging from 1-month to 6-month intramuscular injections) have been successively developed for various suppressive treatments in men, women, and children, which are available in the United States and globally. This mini review aims to summarize the key clinical studies that led to regulatory approval of leuprolide acetate depot suspension for injection.

Preparation and Optimization of Leuprolide Acetate Nanoparticles Using Response Surface Methodology: In Vitro and Ex Vivo Evaluation.

This study aims to develop optimized leuprolide acetate (LA) nanoparticles (NPs) for intranasal delivery in the treatment of Alzheimer's disease. Box-Behnken Design was used to optimize LA polylactide-co-glycolic acid (PLGA) NPs. The independent variables chosen were PLGA concentration, surfactant concentration, and the ratio of water to oil phase, whereas the dependent variables were particle size and % entrapment efficiency. The optimized NPs were evaluated by in vitro drug release study, ex vivo diffusion study, histopathology study, hemolytic stability study, and stability in simulated nasal fluid (SNF). The optimized NPs had particle size of 182.6 ± 1.5 nm, polydispersity index (0.3), % entrapment efficiency (77.3 ± 0.6), and zeta potential (-5.6 mv ±0.2). The in vitro drug release indicated 96% of pure drug release in 6 h, whereas only 66.35% of the drug was released from the optimized formulation at 48 h. The ex vivo diffusion study indicated an apparent permeability coefficient of 5.0 + 0.3 × 104 for drug-containing NPs, which was higher than for plain drug solution (2.0 + 0.2 × 104). Sheep nasal toxicity and hemolytic study proved the safety of formulation. The optimized NPs were found to be stable in SNF. Thus, nanoparticulate formulation of LA was optimized by quality by design approach.

A phase 3, single arm, open-label study evaluating ovarian suppression following 3-month leuprolide acetate for injectable suspension in combination with endocrine therapy in premenopausal subjects with HR+, HER2-negative breast cancer (OVELIA).

TPS608 Background: In US clinical practice, GnRH agonists are widely used to suppress ovarian function in pre/perimenopausal patients with breast cancer that is moderate-to high-risk for recurrence. Despite extensive use of leuprolide acetate (LA) for ovarian suppression, regulatory approval for this indication has not been established in the US. Additionally, existing three month formulations may not reliably provide ovarian suppression, as demonstrated by escapes in estradiol (E2). An extended-release LA product with a 3-month dosing period specifically developed for ovarian suppression in patients with breast cancer could fill this unmet need. TOL2506 is a 3-month, extended-release formulation of 30 mg of LA. This combination of active drug and in situ polymeric extended release technology is expected to deliver higher exposure to drug than the currently available 3-month (22.5 mg) formulations of LA marketed for advanced prostate cancer and potentially reduce escapes in E2 over the dosing period. Methods: TOL2506A (OVELIA) is a phase 3, single arm, open-label study evaluating the effectiveness of TOL2506 to suppress ovarian function in premenopausal women with HR+, HER2-negative breast cancer. Approximately 250 subjects will be enrolled, with 30% aged 40 years or younger. Subjects must be premenopausal women, age 18-49, with a diagnosis of Stage I, II, or III HR+, HER2-negative breast cancer (ER > 1% and/or, PR > 1%, HER2-negative per ASCO CAP guidelines), who are candidates for ovarian suppression with endocrine therapy. For subjects receiving chemotherapy, premenopausal status will be determined, and confirmed by central lab hormone testing, prior to initiating chemotherapy. Male subjects with HR+, HER2-negative breast cancer may also be eligible, but will be evaluated for safety analyses only. Eligible subjects will enter the 48 week treatment period in 2 groups: those receiving tamoxifen concurrently with TOL2506 or those who initiate therapy with an aromatase inhibitor (AI; letrozole, anastrozole, or exemestane) beginning 6 weeks after the first administration of TOL2506, if E2 < 20 pg/mL has been achieved. After Week 12, subjects will be allowed to switch from receiving an AI to receiving tamoxifen or from tamoxifen to AI at the Investigator’s discretion. Subjects will receive 4 doses of TOL2506 every 12 weeks over the 48 week study duration. Achievement of ovarian suppression will be defined as ≥ 90% of subjects with luteinizing hormone (LH) levels < 4 IU/L at Week 6. Secondary endpoints include suppression of LH, E2 (< 20 pg/mL for tamoxifen cohort and < 2.72 pg/mL for AI cohort) and absence of menses at weeks 6, 12, 24, 36, and 48. Clinical trial information: NCT04906395.

In vitro and in vivo evaluations of a 3-month sustained-release microsphere depot formulation of leuprolide acetate

In vitro and in vivo evaluations of a 3-month sustained-release microsphere depot formulation of leuprolide acetate

Fabrication and Release Kinetics of Liposomes Containing Leuprolide Acetate

The present work is focused on the preparation and in vitro release kinetics of liposomal formulation of Leuprolide Acetate. In this work, “Thin Lipid Film Hydration Method” was used for preparation of Leuprolide Acetate loaded liposomes. Prepared liposomal formulations of Leuprolide acetate was evaluated by drug entrapment study, in-vitro drug release kinetics and stability studies. The percentage drug entrapment of Leuprolide acetate for F1 and F2 formulations were found to be 78.14 ± 0.67 and 66.70 ± 0.81% respectively. In-vitro drug release study of liposomal formulations had shown zero order release pattern. Regression co-efficient (R2) value of Zero order kinetics for F1 and F2 formulations were 0.9912 and 0.9676 respectively. After storing formulations for 1 month, stability testing was done at 40C.It was found that all batches were stable. These liposomal formulations of Leuprolide acetate can be formulated for parenteral application to treat prostate cancer and in women, to treat symptoms of endometriosis (overgrowth of uterine lining outside of the uterus) or uterine fibroids.

P1222 - Impact of late dosing on testosterone suppression with two different leuprolide acetate formulations: In situ gel and microsphere – an analysis of US clinical data

P1222 - Impact of late dosing on testosterone suppression with two different leuprolide acetate formulations: In situ gel and microsphere – an analysis of US clinical data

CLO21-014: Impact of Late Dosing on Testosterone Suppression With Two Different Leuprolide Acetate Formulations: In Situ Gel and Microsphere – an Analysis of US Clinical Data

"CLO21-014: Impact of Late Dosing on Testosterone Suppression With Two Different Leuprolide Acetate Formulations: In Situ Gel and Microsphere – an Analysis of US Clinical Data" published on 17 Mar 2021 by National Comprehensive Cancer Network.

Development and Characterization of Leuprolide Acetate Encapsulated PLGA Microspheres for Parenteral Controlled Release Depot Injection

Abstract: Objectives: Polylactic acid (PLA) and copolymer polylactic-co-glycolic acid (PLGA) are the most versatile drug carriers for long acting release injectable (LAI) formulations for small molecules, peptides and macromolecules such as proteins and nucleic acids. The present research work consists of a PLGA based one-month release microsphere formulation of GnRH agonist leuprolide acetate, using double emulsion (W1/O/W2) technique. Materials and Methods: Microparticles were prepared by double emulsion solvent evaporation technique and critical quality attributes of finished products such as drug loading, entrapment efficiency, particle size distribution (PSD), surface porosity, drug distribution within microparticles were analysed. Results and Conclusion: The microspheres have shown the mean particle size of 15.2 μm and suitable particle size distribution pattern ideal for syringe ability. The microparticles were spherical in shape with uniform pore distribution and uniform distribution of API in the polymer matrix. The drug release has been sustained over a month for the microsphere formulation and could be correlated with the testosterone suppression. Key words: Leuprolide, PLGA Microspheres, Double-emulsion technique, Prostate cancer, Controlled release depot Injection.

Effect of implant formation on drug release kinetics of in situ forming implants

In situ forming implants are attractive long-acting implant dosage forms due to their: i) ability to control drug release; ii) simple manufacturing process; and iii) minimally invasive administration. In situ forming implants are typically made of a drug, solvent, and a biocompatible polymer that controls drug release. Once injected in the subcutaneous tissue, they form solid depots through solvent/non-solvent exchange and phase separation of the biodegradable polymer (such as poly (lactic-co-glycolic acid), PLGA and poly (lactic acid), PLA). However, the mechanism of implant formation and the changes in their microstructure that determine drug release behavior are not fully understood. Furthermore, there is no standardized in vitro release testing method for in situ forming implants due to limitations in recreating bio-relevant and reproducible implant formation in vitro with controllable implant shape, dimensions and surface-to-volume ratio. In the present study, bio-relevant implant formation was recreated in vitro by testing five different methods to determine their effect on drug release kinetics, reproducibility, and internal microstructure formation. The leuprolide acetate formulation Eligard® was used as a model in situ-forming implant, consisting of lyophilized leuprolide acetate, and PLGA dissolved in N-methyl pyrrolidone. The results revealed that the in vitro implant formation method is a crucial step in the dissolution testing process that significantly impacts the release profile of in situ forming implants. An implant formation method that utilizes dissolvable polyvinyl alcohol (PVA) films allowed for initial drug burst release control by modulating implant dimensions (i.e. surface area) and resulted in reproducible in vitro release profiles. In addition, implant formation was shown to affect the internal microstructure of in situ forming implant and was the main factor controlling the release profile which consisted of an initial release phase followed by a release plateau (lag phase) and then a second erosion-controlled release phase.

Impact of Late Dosing on Testosterone Suppression with 2 Different Leuprolide Acetate Formulations: In Situ Gel and Microsphere. An Analysis of United States Clinical Data.

Nonadherence to dosing schedules for androgen deprivation therapy increases the risk of testosterone escape for patients with prostate cancer. Two approved formulations of leuprolide acetate, the most commonly prescribed androgen deprivation therapy in the United States, use different extended release delivery technologies: an in situ gel and microspheres. We evaluated the prevalence and impact of late dosing on testosterone suppression for gel and microsphere formulations of leuprolide acetate. We retrospectively analyzed records of patients with prostate cancer treated with gel or microsphere delivery of leuprolide acetate. Analyses used 2 definitions of "month," "28-day" (late dosing after day 28, 84, 112 or 168) and "extended" (late dosing after day 32, 97, 128 and 194). Frequencies of late dosing and associated testosterone values were calculated. A total of 2,038 patients received gel and 8,360 received microsphere formulations of leuprolide acetate. More than 80% and 27% of injections were late for 28-day and extended month, respectively. For 28-day month late injections 10% (gel delivery) and 14% (microsphere delivery) of testosterone values were above 50 ng/dl, and 25% (gel) vs 33% (microsphere) were above 20 ng/dl. For extended month 18% (gel) vs 25% (microsphere) were above 50 ng/dl, and 34% (gel) vs 44% (microsphere) were above 20 ng/dl. Microsphere leuprolide acetate was 1.5 times more likely to have testosterone above 50/20 ng/dl vs gel. Least square mean testosterone was 34 ng/dl (gel) vs 46 ng/dl (microsphere) for 28-day month, and 48 ng/dl (gel) vs 76 ng/dl (microsphere) for extended month. Leuprolide acetate therapies were frequently administered late. Gel formulation demonstrated higher rates of testosterone 50 ng/dl or less and 20 ng/dl or less than microsphere formulation. Optimal testosterone suppression can impact prostate cancer progression and patient survival, and differences in extended release technology for androgen deprivation therapy appear relevant.

PCN174 BUDGET IMPACT OF LEUPROLIDE ACETATE 3-MONTHLY DEPOT FORMULATIONS FOR THE MANAGEMENT OF PATIENTS WITH ADVANCED AND METASTATIC PROSTATE CANCER IN GREECE

Luteinizing hormone-releasing hormone (LHRH) agonists represent the main treatment for the management of patients with advanced and metastatic prostate cancer (amPC). Leuprolide, LHRH agonist, is used as first-line treatment in amPC. Lutrate Depot 22.5 mg is a novel leuprolide acetate formulation, offering a unique double control delivery system. The aim of this study was to evaluate the economic implications of leuprolide acetate 3-monthly (3M) depot formulations, from payer perspective in Greece (EOPYY). A traditional budget-impact model with a 5-year time-horizon was developed. Epidemiological data were obtained from literature and were validated by a local clinical expert. The target population consisted of newly diagnosed amPC patients, since no treatment changes are envisaged in patients with testosterone levels <50ng/dl or 1.735nmol/L. The analysis included currently available leuprolide acetate 3M formulations (Elityran and Leuprol 11.25 mg). Market share predictions were based on internal market research. The model incorporated only drug acquisition costs, obtained from the National Price Bulletin, applying the mandatory price discounts, rebates and clawbacks. The estimated number of patients eligible to receive leuprolide was 914 in the first model year and 4,883 patients over a 5-year horizon. About 414 patients (44% of the total population) was predicted to receive treatment with Lutrate Depot in the first year and 2,197 patients over 5-years. Introduction of Lutrate Depot in the market would lead to budget savings of €5,171 to €117,747 in the first and fifth model-years, respectively. The cumulative budget-impact over 5-years resulted in cost-savings of €129,071 for the payer (€6,194,671 vs €6,323,742). According to published data LHRH agonists have similar clinical efficacy and safety. The results of the model suggest that Lutrate Depot 22.5mg over the available 3M depot formulations could lead to considerable savings for EOPYY; consisting Lutrate Depot 22.5mg an alternative cost-saving treatment option for eligible amPC patients in Greece.

Low incidence of microsurges with biodegradable polymer-delivered, subcutaneously-administered leuprolide acetate in prostate cancer patients.

158 Background: Androgen deprivation therapy is a foundational treatment of advanced prostate cancer (PCa) with the primary objective of suppressing circulating androgens.Consistent drug delivery with long-acting leuprolide acetate (LA) formulations is important in providing continuous testosterone (T) suppression throughout the course of treatment without T rising above castrate level (T breakthrough). To assess subcutaneously-administered LA (SC-LA) maintenance of T levels in PCa patients, the incidence of microsurges was evaluated in 4 pivotal trials. Methods: In 4 open-label, fixed-dose, pivotal trials, 424 eugonadal prostate cancer patients (age 40-86) who achieved medical castration (T&lt;50 ng/dL) while on the first administration of SC-LA 7.5, 22.5, 30, or 45 mg, lasting 1, 3, 4, or 6 months, respectively, were evaluated for microsurges. A microsurge was defined as an absolute increase in T level of at least 25 ng/dL during the 4 week period after the second study dose was administered. T was measured 2-4 times on day 0 and once on days 1, 2, 3, 7, and every week until the next dose through the end of the studies. Results: Across the individual studies, 8 patients out of 424 (range 0.9-3.4% by dose, pooled 1.9%) experienced a microsurge during the acute period after the second SC-LA dose (Table). 6 of these 8 patients remained below castrate level at the peak of the surge. Conclusions: SC-LA demonstrated a very low incidence of T breakthroughs and microsurges in PCa patients and only 2 of 424 patients experienced a T microsurge above castrate levels. Limiting the occurrence of T levels above castrate levels may have clinical implications with respect to prolonged progression-free survival. [Table: see text]

A New Sustained-release, 3-Month Leuprolide Acetate Formulation Achieves and Maintains Castrate Concentrations of Testosterone in Patients With Prostate Cancer

PurposeThis clinical trial investigated the effectiveness, pharmacokinetic properties, and safety profile of leuprolide acetate 22.5-mg depot, a new 3-month leuprolide depot formulation, as androgen deprivation therapy for patients with prostate cancer. MethodsA Phase III, open-label, multicenter study design for patients with prostate cancer, with patient inclusion assessed by the investigative site as patient's appropriate for androgen deprivation therapy. Patients received 2 separate intramuscular injections of leuprolide acetate 22.5-mg depot for a 3-month depot interval of therapeutic effect. Plasma testosterone concentrations were determined throughout the study. The primary efficacy analysis was the percentage of patients who achieve and maintain castrate testosterone levels (≤50 ng/mL) from days 28–168. Secondary end points included luteinizing hormone, follicle-stimulating hormone, prostate-specific antigen, and safety assessments. A pharmacokinetic study was also conducted in a subset of 30 patients. FindingsAll 163 patients enrolled in the study received at least 1 dose of study drug; 162 of them were fully evaluable and 151 completed the study. Castrate levels of testosterone were achieved and maintained from days 28–168 in 96.8% (95% CI, 92.5%–98.7%) of patients. Five patients presented with sporadic testosterone levels >50 ng/dL. By day 28, of the 161 patients, 150 (99.4%) had achieved castrate levels, and 127 (78.9%) had achieved testosterone concentrations ≤20 ng/dL. At study end, 149 of 151 patients (98.7%) patients achieved castrate testosterone levels, with 142 of 151 (94.0%) having testosterone levels ≤20 ng/dL. At study end, mean luteinizing hormone and follicle-stimulating hormone concentrations had decreased from baseline to below the lower limit of quantitation and below baseline levels, respectively, whereas mean serum prostate-specific antigen was reduced by 94.7% from baseline. Most patients (>96%) had no change in their World Health Organization/Eastern Cooperative Oncology Group score, whereby 84.0% of patients had a baseline score of 0. Bone pain, urinary pain, and urinary symptoms were infrequent and remained so throughout the study. After administration, leuprolide concentrations increased rapidly. The peak was followed by a decline up to day 28, maintaining sustained drug levels until the following dose on day 84. The most common related treatment-emergent adverse events, detected in >5% of patients, were hot flushes, fatigue, and injection site pain reported by 77.3%, 9.8%, and 9.2% of patients, respectively. ImplicationsLeuprolide acetate 22.5-mg depot was effective in achieving and maintaining testosterone suppression. Safety and tolerability profiles were consistent with established profiles of androgen deprivation therapy. Clinical Trials.gov identifier: NCT01415960.

Pharmacokinetic and pharmacodynamic comparison of subcutaneous versus intramuscular leuprolide acetate formulations in male subjects.

The aim of this study was to compare the pharmacokinetics (PK) and pharmacodynamics (PD) of two distinct formulations of leuprolide acetate (LA); subcutaneous (SC) injection and intramuscular (IM) injection. A total of 32 healthy men were randomized to receive a single 7.5 mg injection of SC-LA (n = 16) or IM-LA (n = 16) in this phase I, open-label, parallel-group study. PK was assessed via LA concentrations, and PD via serum luteinizing hormone (LH) and testosterone (T) concentrations. The initial surge of LA was higher for IM-LA than SC-LA (Cmax 27 ± 4.9 versus 19 ± 8.0 ng/ml, respectively), with a shorter tmax (1.0 ± 0.4 versus 2.1 ± 0.8 h). The duration of quantifiable LA concentration was longer for SC-LA (up to 56 versus 42 days for SC-LA and IM-LA, respectively). Median LH concentrations in both groups rapidly increased, followed by gradual decrease. However, SC-LA demonstrated a longer duration of LH suppression, with median levels remaining below 1.0 IU/l through Day 56 compared with IM-LA where LH started to rise by Day 35. Consequently, serum T began to increase by Day 42 in the IM-LA group, with only four subjects maintaining levels ⩽50 ng/dl, compared with 14 subjects in the SC-LA group. By Day 56, 13 SC-LA subjects maintained serum T levels ⩽50 ng/dl. Both SC-LA and IM-LA were well tolerated. Both formulations demonstrated consistent delivery of drug over 1 month; however, SC-LA provided a longer duration of action than expected based on the dosing interval. This profile suggests that SC-LA will provide effective suppression of T over a longer period of time, permitting greater injection scheduling flexibility.

Head-to-head pharmacokinetic and pharmacodynamic comparison of subcutaneous versus intramuscular leuprorelin acetate formulations in male patients.

e589 Background: Leuprolide acetate (LA) is the standard-of-care luteinizing hormone-releasing hormone (LHRH) agonist used to suppress serum testosterone (T) in the treatment of advanced prostate cancer. There are currently two LA formulations available: a controlled-release implant injected subcutaneously (SC) or a microsphere intra-muscular (IM) injection. The study compared the pharmacokinetics/pharmacodynamics of both formulations at the same one-month dose. Methods: Thirty-two healthy men were randomized to receive a single 7.5 mg injection of SC-LA (n = 16) or IM-LA (n = 16) in this phase 1, open-label, parallel-group study. Serum LA, T, and luteinizing hormone (LH) were assessed. Results: The initial surge of LA was higher for IM-LA than SC-LA (Cmax 27±4.9 vs. 19±8.0 ng/mL, respectively), with a shorter tmax (1.0±0.4 vs. 2.1±0.8 hrs). Mean serum LA remained above the level of quantification (LOQ, 50 pg/mL) through Day 49 for SC-LA, whereas for IM-LA, mean serum LA dropped below the LOQ after Day 28. Median LH concentration remained low at Day 56 in the SC-LA group, whereas LH levels began to rise after Day 35 in the IM-LA group. Consequently, serum T began to increase by Day 42 in the IM-LA group. By Day 56, 13 SC-LA subjects maintained serum T levels ≤ 50 ng/dL vs. 0 in the IM-LA group. Both SC-LA and IM-LA were well tolerated, however SC-LA subjects experienced more mild injection site disorders compared to IM-LA. Conclusions: The initial surge of LA was higher for IM-LA than SC-LA (Cmax 27±4.9 vs. 19±8.0 ng/mL, respectively), with a shorter tmax (1.0±0.4 vs. 2.1±0.8 hrs). Mean serum LA remained above the level of quantification (LOQ, 50 pg/mL) through Day 49 for SC-LA, whereas for IM-LA, mean serum LA dropped below the LOQ after Day 28. Median LH concentration remained low at Day 56 in the SC-LA group, whereas LH levels began to rise after Day 35 in the IM-LA group. Consequently, serum T began to increase by Day 42 in the IM-LA group. By Day 56, 13 SC-LA subjects maintained serum T levels ≤ 50 ng/dL vs. 0 in the IM-LA group. Both SC-LA and IM-LA were well tolerated, however SC-LA subjects experienced more mild injection site disorders compared to IM-LA.

Comparative in vitro release and clinical pharmacokinetics of leuprolide from Luphere 3M Depot, a 3-month release formulation of leuprolide acetate

A 3-month depot formulation of leuprolide acetate (Luphere 3M Depot) with a mean microsphere diameter of 22.3 μm was prepared aseptically by spray-drying glacial acetic acid solution of the drug and polylactic acid, and lyophilization in a d-mannitol solution. The encapsulation efficiency and loading content of the drug in the Luphere 3M Depot were 94.7% and 9.92% (w/w), respectively. The in vitro release of leuprolide from the depot was substantially delayed and the release profile was similar to that of Lucrin Depot (Abbott Korea, Korea). The safety and pharmacokinetics of leuprolide were investigated over a period of 42 days in 20 prostate cancer patients following a subcutaneous injection of Luphere 3M or Lucrin Depot suspensions (leuprolide acetate dose of 11.25 mg) in a multi-center, randomized, single dose, parallel study. Both formulations were well tolerated by the patients and no serious adverse effects were observed during and after the study. No significant differences were observed in the maximum serum concentration (Cmax) and area under the curve (AUClast) of leuprolide between the two formulations. The results suggest comparable safety and efficacy profiles of Luphere 3M Depot and Lucrin Depot in clinical situations.

Formulation and characterization of a liquid crystalline hexagonal mesophase region of phosphatidylcholine, sorbitan monooleate, and tocopherol acetate for sustained delivery of leuprolide acetate

Although liquid crystal (LC) systems have been studied before, their utility in drug delivery applications has not been explored in depth. This study examined the development of a 1-month sustained release formulation of leuprolide acetate using an in situ-forming LC matrix. The phase progression upon water absorption was tested through construction of ternary phase diagrams of phosphatidylcholine, sorbitan monooleate, and tocopherol acetate (TA) at increasing water content. Small angle X-ray scattering revealed the presence of lamellar and hexagonal mesophases. The physicochemical characteristics and in vitro drug release were evaluated as a function of the ternary component ratio and its resultant phase behavior. Formulations with increased water uptake capacity displayed greater drug release and enhanced erodability. Removal of TA resulted in increased water uptake capacity and drug release, where 8% (w/w) TA was determined as the critical concentration threshold for divergence of release profiles. In conclusion, characterization of the resultant HII mesophase region provided information of the impact the individual components have on the physicochemical properties and potential drug release mechanisms. This high mitigating impact of TA on drug release indicates the use of TA as a tailoring agent, broadening the therapeutic applications of this LC system.

Intramuscular depot formulations of leuprolide acetate suppress testosterone levels below a 20 ng/dL threshold: a retrospective analysis of two Phase III studies.

IntroductionAndrogen deprivation therapy (ADT) with gonadotropin-releasing hormone (GnRH) analogs is a standard treatment for advanced prostate cancer. GnRH analog therapy can reduce testosterone to “castrate” levels, historically defined as <50 ng/dL. With the advent of newer assays, a lower threshold of <20 ng/dL has recently been proposed. We report the results of a retrospective analysis of two Phase III trials of 4- and 6-month depot microsphere formulations of leuprolide acetate (LA), a GnRH agonist that has previously demonstrated efficacy in testosterone suppression to <50 ng/dL in patients on ADT. This analysis investigates the ability of these LA formulations to suppress to ≤20 ng/dL levels.MethodsIn two of five AbbVie/Abbott clinical trials of microsphere formulations of LA for ADT, analytic technology permitting testosterone detection as low as 3 ng/dL was used and thus was selected for this analysis. Both trials were open-label, fixed-dose studies in prostate cancer patients, naïve to ADT. Patients received either 30 mg (4-month formulation; n=49) or 45 mg (6-month formulation; n=151) depot injections of LA microspheres. Treatment duration was up to 32 weeks for the 4-month formulation and 48 weeks for the 6-month formulation. The proportion of patients achieving the 20 ng/dL threshold was determined every 4 weeks.ResultsPooled analysis showed that 152 of 193 (79%) of patients achieved serum testosterone levels of ≤20 ng/dL at 4 weeks, and sustained the improvement at week 24 (169/189, 89%). Additionally, in the 6-month study, 127/135 (94.1%) patients were suppressed to ≤20 ng/dL at 48 weeks.ConclusionBoth 4- and 6-month intramuscular depot formulations of LA achieved and maintained mean serum testosterone levels ≤20 ng/dL in the vast majority of patients as early as 4 weeks following treatment initiation. Additional research on the clinical relevance of this lower testosterone threshold is warranted.