Mirena (Levonorgestrel intrauterine system): a successful novel drug delivery option in contraception

Magnetic Resonance Imaging-Based Classification Systems for Informing Better Outcomes of Adenomyosis After Ultrasound-Guided High-Intensity Focused Ultrasound Ablating Surgery

BACKGROUND

A referenced MRI-based classification associated with focused ultrasound ablation surgery (FUAS) outcomes is lacking in adenomyosis.

PURPOSE

To identify an MRI-based classification system for informing the FUAS outcomes.

STUDY TYPE

Retrospective.

POPULATION

Patients with FUAS for adenomyosis, were divided into a training set (N = 643; 355 with post-FUAS gonadotropin-releasing hormone/levonorgestrel, 288 without post-FUAS therapy) and an external validation set (N = 135; all without post-FUAS therapy).

FIELD STRENGTH/SEQUENCE

1.5 T, turbo spin-echo T2-weighted imaging and single-shot echo-planar diffusion-weighted imaging sequences.

ASSESSMENT

Five MRI-based adenomyosis classifications: classification 1 (C1) (diffuse, focal, and mild), C2 (intrinsic, extrinsic, intramural, and indeterminate), C3 (internal, adenomyomas, and external), C4 (six subtypes on areas [internal or external] and volumes [<1/3 or ≥2/3]), and C5 (internal [asymmetric or symmetric], external, intramural, full thickness [asymmetric or symmetric]) for FUAS outcomes (symptom relief and recurrence).

STATISTICAL TESTS

The optimal classification was significantly associated with the most subtypes of FUAS outcomes. Relating to the timing of recurrence was measured using Cox regression analysis and median recurrence time was estimated by a Kaplan-Meier curve. A P value <0.05 was considered statistically significant.

RESULTS

Dysmenorrhea relief and recurrence were only associated with C2 in training patients undergoing FUAS alone. Compared with other subtypes, the extrinsic subtype of C2 was significantly associated with dysmenorrhea recurrence in the FUAS group. Besides, the median dysmenorrhea recurrence time of extrinsic subtype was significantly shorter than that of other subtypes (42.0 months vs. 50.3 months). In the validation cohort, C2 was confirmed as the optimal system and its extrinsic subtype was confirmed to have a significantly shorter dysmenorrhea recurrence time than other subtypes.

DATA CONCLUSION

Classification 2 can inform dysmenorrhea relief and recurrence in patients with adenomyosis undergoing FAUS only. Itsextrinsic subtype was associated with an earlier onset of dysmenorrhea recurrence after treatment.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 5.

Feasibility and Effectiveness of Hysteroscopic Suture Fixation of the Levonorgestrel-Releasing Intrauterine System in the Treatment of Adenomyosis

STUDY OBJECTIVE

To evaluate the feasibility and effectiveness of hysteroscopic suture fixation of the levonorgestrel-releasing intrauterine system (LNG-IUS) for the treatment of adenomyosis.

DESIGN

A retrospective case series.

SETTING

Two teaching hospitals with the technology of hysteroscopic suture fixation of the LNG-IUS.

PATIENTS

The study reviewed 79 adenomyosis patients who received the hysteroscopic suture fixation of the LNG-IUS from January 2021 to May 2022.

INTERVENTION

Hysteroscopic suture fixation of the LNG-IUS to the posterior uterine wall with nondissolvable suture.

MEASUREMENTS AND MAIN RESULTS

All patients underwent one-year postoperative follow-up to evaluate the LNG-IUS expulsion rate, postoperative efficacy, and side effects. Two patients (2.6%) experienced expulsion of the LNG-IUS at 8 months and 12 months postoperatively, respectively. The visual analog pain scale, pictorial blood loss assessment chart score and carbohydrate antigen 125 markedly decreased after the suture fixation of the LNG-IUS compared with baseline in all patients (p <.001). Hemoglobin increased significantly (p <.001). The most common side effect was irregular bleeding, which accounted for 44.3%. The second common side effect was weight gain, which accounted for 29.2%. The composite effectiveness based on pain and bleeding showed that the effective treatment rates at 1, 3, 6, and 12 months after surgery were 92.4%, 97.4%, 96.2%, and 97.4% respectively.

CONCLUSIONS

Hysteroscopic suture fixation of the LNG-IUS to the uterine fundus was associated with low expulsion rates and significantly improved dysmenorrhea and bleeding.

Transvaginal ultrasound- and laparoscopy-guided percutaneous microwave ablation for adenomyosis has short- and long-term benefits: a single-center study

OBJECTIVES

Transvaginal ultrasound- and laparoscopy-guided percutaneous microwave ablation (TLPMA) is a minimally invasive alternative technique with low risk, fast recovery and few side effects. We aimed to evaluate the safety and long-term efficacy of TLPMA for treating adenomyosis.

METHODS

We included 79 patients with symptomatic adenomyosis who underwent TLPMA and 44 patients with adenomyosis who received the levonorgestrel-releasing intrauterine system (LNG-IUS). We evaluated the role of laparoscopy in TLPMA as well as the short- and long-term effects of TLPMA.

RESULTS

The mean age of the 79 patients who underwent TLPMA was 41.8 years. There was no difference in the mean age between the TLPMA and LNG-IUS groups. Laparoscopy could help to separate pelvic adhesions, provide a wide antenna path, and observe the uterine surface and bowel movement. No major complications were found in patients who underwent TLPMA. There was a significant post-treatment reduction in both the uterine and lesion volumes (p < 0.001). After a median follow-up duration of 36 months (range: 1-60 months), the uterine and lesion volumes remained stable. Additionally, most patients remained without dysmenorrhea, which confirms the long-term efficacy of TLPMA.

CONCLUSIONS

TLPMA is a feasible, minimally invasive technique for the treatment of adenomyosis, which significantly decreases the uterine and lesion volumes and has a good long-term effect.

An estriol-eluting pessary to treat pelvic organ prolapse

Pelvic organ prolapse affects up to 50% of parous women. Commonly used treatment options have unwelcome attributes; pessaries can cause erosion and estrogen creams need to be applied frequently, which is inconvenient and difficult to administer. This study involved the development of an estriol-releasing pessary utilising 3D printing molds. We incorporated varying amounts of estriol (1%, 10% and 15%) into the silicone pessary. We optimised the mechanical aspects of the pessary so it had a similar strength to commercially available pessaries. We investigated estriol release from the pessary over 3 months. We explored possible interactions between the drug and polymers via FTIR. The MED-4870 silicone ring with similar mechanical strength to pessaries currently used to treat pelvic organ prolapse. The medical pessaries present a sustained release in simulated vaginal fluid over 3 months. The pessary with 10% estriol delivered the optimal dose at 0.8 mg each week. Mechanical strength of this pessary showed no difference after emersion in simulated vaginal fluid for 3-month, supporting the long-term application. An estriol-loaded pessary was successfully developed to treat pelvic organ prolapse with sustained release of estriol over 3 months. This pessary provides promising potential to treat pelvic organ prolapse and vaginal atrophy.

Utility of the Levonorgestrel-Releasing Intrauterine System in the Treatment of Abnormal Uterine Bleeding and Dysmenorrhea: A Narrative Review

INTRODUCTION

We undertook a literature review of the use of levonorgestrel-releasing intrauterine devices when utilized for heavy menstrual bleeding and/or dysmenorrhea.

METHODS

A narrative review of articles in the Scopus and Medline databases was conducted.

RESULTS

A number of options exist for the management of both abnormal uterine bleeding (AUB) and dysmenorrhea, and evidence is accumulating that the insertion of a levonorgestrel-releasing intrauterine system (LNG-IUS) represents a useful option for their long-term treatment. The idea of using a progestogen released in utero was initially conceived to achieve long-term contraception, but it was quickly found that these systems could be utilized for a number of therapeutic applications. The first device to be made commercially available, Progestasert, was withdrawn from the market because, in the event of contraceptive failure, it caused a disproportionate percentage of extrauterine pregnancies. On the other hand, the LNG-IUS continues to be successfully utilized in its various variants, releasing 20, 13, or 8 μg/day. These devices have a respective duration of action of 7 (possibly 8), 5, and 3 years, and there exist versions of frameless systems affixed to the myometrium of the uterine fundus. In the present review, following a brief description of the major causes of AUB and dysmenorrhea, the molecular bases for the use of the LNG-IUS are summarized. This is followed by a compendium of its use in AUB and dysmenorrhea, concluding that the insertion of the system improves the quality of life, reduces menstrual blood loss better than other medical therapies, and decreases the extent of dysmenorrhea and pelvic pain. In addition, there is no evidence of a significant difference in these outcomes when the use of the LNG-IUS was compared with improvements offered by endometrial ablation or hysterectomy. Possibly, the most important mechanism of action of the system consists of its ability to induce amenorrhea, which effectively eliminates heavy bleeding and dysmenorrhea. However, no method is ideal for every woman, and, in the case of the LNG-IUS, younger age and severe dysmenorrhea seem to be associated with a higher risk of discontinuation.

CONCLUSION

The higher-dose LNG-IUS is a useful tool for HMB and dysmenorrhea in women of all ages. The low cost and ease of use make the LNG-IUS an attractive option, especially when contraception is also desired.

Women's preferences and acceptance for different drug delivery routes and products

To use or not to use, that is the first decision to take regarding a drug product. This mandatory step for adherence dictates product efficacy. The determinants for such decision do not only rely on the priority of the therapeutic or preventive strategy, but are related to a complex network of perceptions, preferences, personal and cultural backgrounds, and results from previous experiences. Women's preferences for dosage forms and even for drug delivery routes have been mainly studied in the fields of contraception and HIV prevention (and their related multipurpose approaches). Much less attention has been devoted to other therapeutic or preventive strategies. In a time when patient-centred approaches and shared decisions are increasingly valued, considering women's preferences and their main determinants is essential for product development and selection. Such products will be more likely to be chosen and used as intended, increasing efficacy, and reducing the overall costs related with these treatments. This knowledge shall be integrated in early stages of product development. This article reviews the state of the art related with women's preferences and acceptance for different dosage forms and drug delivery routes involved in women's health. The methodologies used for collecting these data and their major drawbacks are discussed. Results obtained from acceptability studies and the main determinants for selection of preventive and treatment drug products are discussed as tools for new developments in the field.

Women-specific routes of administration for drugs: A critical overview

The woman's body presents a number of unique anatomical features that can constitute valuable routes for the administration of drugs, either for local or systemic action. These are associated with genitalia (vaginal, endocervical, intrauterine, intrafallopian and intraovarian routes), changes occurring during pregnancy (extra-amniotic, intra-amniotic and intraplacental routes) and the female breast (breast intraductal route). While the vaginal administration of drug products is common, other routes have limited clinical application and are fairly unknown even for scientists involved in drug delivery science. Understanding the possibilities and limitations of women-specific routes is of key importance for the development of new preventative, diagnostic and therapeutic strategies that will ultimately contribute to the advancement of women's health. This article provides an overview on women-specific routes for the administration of drugs, focusing on aspects such as biological features pertaining to drug delivery, relevance in current clinical practice, available drug dosage forms/delivery systems and administration techniques, as well as recent trends in the field.

Ultrasound-guided transvaginal radiofrequency ablation combined with levonorgestrel-releasing intrauterine system for symptomatic uterine adenomyosis treatment

OBJECTIVE

To evaluate the clinical outcomes of transvaginal ultrasound-guided radiofrequency ablation (RFA) combined with a levonorgestrel-releasing intrauterine system (LNG-IUS) for the treatment of symptomatic uterine adenomyosis.

METHODS

Patients with symptomatic uterine adenomyosis treated with ultrasound-guided RFA in combined with an LNG-IUS from January 2013 to January 2016 and followed up for 3 years after treatment were selected. Assessment endpoints included the uterine volume reduction rate, dysmenorrheal score, symptom severity score and adverse events.

RESULTS

Among the 72 patients, 64 completed the 3-year follow-up evaluations after treatment. No LNG-IUS expulsion was reported. Dysmenorrhea and symptom severity scores statistically significantly declined after the combined treatment of RFA and LNG-IUS was administered. The uterine volume significantly decreased, and the average reduction rate was 55%.

CONCLUSION

Ultrasound-guided RFA combined with an LNG-IUS might be a simple, safe and effective alternative for the treatment of symptomatic adenomyosis.

Biomaterials and Contraception: Promises and Pitfalls

The present state of reproductive and sexual health around the world reveals disparities in contraceptive use and effectiveness. Unintended pregnancy and sexually transmitted infection transmission rates remain high even with current prevention methods. The 20th century saw a contraceptive revolution with biomedical innovation driving the success of new contraceptive technologies with central design concepts and materials. Current modalities can be broadly categorized according to their mode of function: reversible methods such as physical/chemical barriers or hormonal delivery devices via systemic (transdermal and subcutaneous) or localized (intrauterine and intravaginal) administration, and nonreversible sterilization procedures such as tubal ligation and vasectomy. Contraceptive biomaterials are at present dominated by well-characterized elastomers such as polydimethylsiloxane and ethylene vinyl acetate due to their favorable material properties and versatility. Contraceptives alter the normal function of cellular components in the reproductive systems to impair fertility. The purpose of this review is to highlight the bioengineering design of existing methods, explore novel adaptations, and address notable shortcomings in current contraceptive technologies.

Benefits of vaginal dinoprostone administration prior to levonorgestrel-releasing intrauterine system insertion in women delivered only by elective cesarean section: a randomized double-blinded clinical trial

PURPOSE

This study aimed at investigating the efficacy and safety of dinoprostone 3 mg vaginally prior to levonorgestrel-releasing intrauterine system (LNG-IUS) insertion in women undergoing elective cesarean delivery (CD).

METHODS

We conducted a prospective, randomized, double-blinded, placebo-controlled trial at family planning clinic of Cairo University hospitals from August 2019 to January 2020. We included 200 women aged ≥ 18 years who previously delivered by elective CD willing to receive LNG-IUS. Women were randomly assigned with a 1:1 allocation ratio to receive 3 mg vaginal dinoprostone or placebo tablets two hours before LNG-IUS insertion. Our main outcomes were patient-reported pain during insertion and 30 min post-procedure, ease of insertion, satisfaction, duration of insertion, and different side effects.

RESULTS

Patient-perceived pain during LNG-IUS insertion was significantly reduced in dinoprostone compared to placebo (4.1 ± 1.7 vs 6.4 ± 1.3; p < 0.001). Dinoprostone reduced pain scores 30 min post-procedure compared to placebo, but the difference was not statistically significant (3.5 ± 1.1 vs 3.7 ± 1.6; p = 0.25). Satisfaction score was higher in dinoprostone compared to placebo (7.9 ± 1.0 vs 5.9 ± 0.8; p < 0.001). The insertion was significantly easier and shorter in dinoprostone than placebo (3.9 ± 1.1 vs 5.9 ± 1.1; p < 0.001) and (5.6 ± 0.9 vs 7.2 ± 0.8; p < 0.001), respectively. Adverse events were not significantly different between both groups.

CONCLUSION

Dinoprostone administration 2 h before LNG-IUS insertion in women delivered by elective CD effectively reduced pain during insertion and 30 min post-procedure. Women received dinoprostone had easier and shorter insertion and were more satisfied with tolerable side effects.

Differences in continuation rates and early removal between contraceptive and therapeutic use of the levonorgestrel-releasing intrauterine system 52 mg

Objective: To investigate differences in continuation rates between contraceptive and therapeutic use of the levonorgestrel-releasing intrauterine system 52 mg (LNG-IUS) and factors associated with early removal.Methods: Study design: Retrospective consecutive cohort design.Cohort: Women with the insertion of the LNG-IUS for contraceptive or therapeutic use from 1 January 2006 through 1 January 2009 at the Zuyderland Medical Centre, The Netherlands, with a follow-up of 5 years. The continuation period and reasons of early removal were noted. Univariable and multivariable analysis were performed.Results: Follow-up was possible in 2481 women, 1855 (74.8%) in the contraception group, and 626 (25.2%) in the therapy group. Multivariable Cox proportional hazards models showed, that therapeutic use was associated with an increased risk of early removal of the LNG-IUS (HR 1.23; 95% CI 1.08-1.41), as was having one child (HR 1.20; 95% CI 1.04-1.38), and a decreased risk with advancing age (HR 0.96; 95% CI 0.95-0.97). In both groups, an unacceptable bleeding pattern and adverse events were the main reasons of early removal, resulting in very low continuation rates over the years.Conclusion: Therapeutic use, having one child and a younger age are independent risk factors of early removal of the LNG-IUS, in contrast with previous LNG-IUS use which is associated with a lower risk. In both the contraception group and the therapy group, the main reasons for LNG-IUS discontinuation are continuation with a new LNG-IUS, and no more need for an LNG-IUS (for contraception or therapy). An unacceptable bleeding pattern or adverse events are associated with the lowest continuation rates in both groups.

Towards a dapivirine and levonorgestrel multipurpose vaginal ring: Investigations into the reaction between levonorgestrel and addition-cure silicone elastomers

With a dapivirine-releasing vaginal ring having successfully completed late-stage clinical testing for HIV prevention and currently undergoing regulatory review, there is now growing interest in next-generation multipurpose prevention technologies that seek to combine antiretroviral and contraceptive drugs within a single product. Here, we focus on ongoing efforts to develop a silicone elastomer vaginal ring releasing both dapivirine and levonorgestrel. Specifically, we evaluate various strategies aimed at both better understanding and reducing the tendency of levonorgestrel to bind with the elastomer, including: (i) formulation and post-manufacturing strategies aimed at reducing the extent of levonorgestrel reaction with addition-cure silicone elastomers; (ii) evaluation of a simple silicone system to model the complex elastomer; (iii) use of model compounds representing the enone and ethinyl moieties of levonorgestrel to probe the mode of addition of levonorgestrel to addition-cure silicone elastomers; and (iv) solution and solid-state ¹³C NMR analysis to probe the structural features of the levonorgestrel-silicone system. The results demonstrate that both the enone and ethinyl groups within levonorgestrel undergo hydrosilylation reactions with the hydrosiloxane groups in the silicone elastomer leading to covalent binding. The results also highlight potential strategies for further optimising the dapivirine + levonorgestrel silicone vaginal ring formulation to ensure that the levonorgestrel is available for release.

Combined therapeutic effects of HIFU, GnRH-a and LNG-IUS for the treatment of severe adenomyosis

OBJECTIVE

To evaluate the combined efficacy of high-intensity focused ultrasound (HIFU), gonadotropin-releasing hormone agonist (GnRH-a) and the levonorgestrel-releasing intrauterine system (LNG-IUS) for the treatment of severe adenomyosis.

METHOD

Four hundred and sixty-six patients with adenomyosis admitted to the Department of Gynecology of Shanghai First Maternity and Infant Hospital underwent HIFU treatment, and then were consecutively administered with GnRH-a 1 d, 1 month and 3 months after HIFU treatment. The uterine size was then measured with ultrasound or MRI 2-4 weeks after three cycles of GnRH-a injection. The LNG-IUS was then inserted when the uterine length less than 9 cm. The visual analog scale (VAS), verbal rating scale (VRS), menstrual volume score, uterus volume, MRI, serum levels of hemoglobin and CA125 were measured at pre and 3-, 6-, 12-month post-HIFU.

RESULTS

Dysmenorrhea and menorrhagia significantly relieved after combined treatment with HIFU, GnRH-a and the LNS-IUS. The uterine volume shrank and returned to its normal size. The serum CA-125 level was reduced to the normal level after the combined treatment.

CONCLUSIONS

The combined therapeutic regimen of HIFU, GnRH-a and LNS-IUS is safe, effective and efficient for curing severe adenomyosis.

Clinical efficacy of adenomyomectomy using "H" type incision combined with Mirena in the treatment of adenomyosis

To evaluate the clinical efficacy and safety of adenomyomectomy using "H" type incision combined with Mirena (LNG-IUS) in the treatment of adenomyosis.A total of 57 women with adenomyosis who underwent adenomyomectomy using "H" type incision combined with LNG-IUS were selected. Visual analog scale (VAS), menstrual flow, uterine volume, serum CA125 levels and hemoglobin amounts were compared before and after the surgery. Meanwhile, postoperative pregnancy, adverse reactions, and recurrence were observed.VAS score, menstrual flow, uterine volume, and serum CA125 levels in 53 patients were significantly reduced after surgery (P < . 001). Moreover, statistical significances were obtained for VAS score at 13 and 6 months, menstrual flow at 1, 3, 6, 12, and 24 months, uterine volume at 1, 3, 6, 12, 24, and 36 months and CA125 levels at 1 and 3 months (P < .05). Of the 5 patients with fertility requirements, 1 became pregnant after IVF-ET, progressed to preterm, and delivered healthy twins. Among all related adverse reactions, amenorrhea was the most common (n = 20, 37.7%). There were no cases of LNG-IUS removal, ectopia, expulsion, and incarceration, except in 2 patients due to pregnancy, 1 due to uterine bleeding, and 1 due to Mirena perforation from incision of the uterine fundus. All patients showed no relapse.Adenomyomectomy using "H" type incision combined with Mirena constitutes a novel and effective conservative surgical procedure for adenomyosis treatment.

Timing of insertion of levonorgestrel-releasing intrauterine system: a randomised controlled trial

OBJECTIVE

The objective was to assess whether patient-perceived pain during the insertion of the levonorgestrel-releasing intrauterine system (LNG-IUS) depends on the timing during the menstrual cycle.

DESIGN

A stratified two-armed non-inferiority randomised controlled trial.

SETTING

Large teaching hospital in Veldhoven, the Netherlands.

SAMPLE

From October 2013 to May 2014, 60 nulliparous and 60 multiparous women were randomised. Eight women withdrew after randomisation and before insertion took place: therefore, data from 112 women were collected and analysed.

METHODS

Women were randomised to the groups 'during menstruation' (i.e. days 1-7 of menstruation) or 'outside menstruation' (i.e. any day of the cycle after menstruation without the presence of vaginal blood loss) in a ratio of 1 : 1.

MAIN OUTCOME MEASURES

The primary outcome was pain during insertion, measured by the visual analogue scale (VAS, 0-100 mm). Second, we analysed ease of insertion, bleeding pattern, satisfaction, pregnancy, and expulsion rate. The follow-up time was 3 months.

RESULTS

The mean VAS score for nulliparous women was 74 mm (95% confidence interval, 95% CI 67-81) in the 'during menstruation' group, compared with 66 mm (95% CI 59-74) in the 'outside menstruation' group (P = 0.14). The mean VAS score for multiparous women was 30 mm (95% CI 20-40) in the 'during menstruation group', compared with 43 mm (95% CI 32-53) in the 'outside menstruation' group (P = 0.08). There was no difference between the stratified 'during menstruation' group and the 'outside menstruation' group with regards to ease of insertion, satisfaction, bleeding pattern, and median spotting and bleeding days for the use of the LNG-IUS 3 months after insertion.

CONCLUSIONS

As we did not find that the level of pain perceived during insertion was higher during menstruation, compared with outside menstruation, we conclude that the LNG-IUS can be inserted at any time during the menstrual cycle, especially in the case of nulliparous women.

TWEETABLE ABSTRACT

We conducted an RCT on time of insertion of LNG-IUS. We conclude that the LNG-IUS can be inserted at any time.

Solid state 13C NMR spectroscopy provides direct evidence for reaction between ethinyl estradiol and a silicone elastomer vaginal ring drug delivery system

Steroid molecules have a long history of incorporation into silicone elastomer materials for controlled release drug delivery applications. Previously, based on in vitro release testing and drug content analysis, we demonstrated indirectly that the contraceptive progestin levonorgestrel (LNG) chemically and irreversibly binds to addition cure silicone elastomers, presumably via a hydrosilylation reaction between the levonorgestrel ethynyl group and the hydrosilane groups in the poly(dimethylsiloxane-co-methylhydrosiloxane) crosslinker of the silicone elastomer. Here, for the first time, we report that solid state ¹³C nuclear magnetic resonance (NMR) spectroscopy provides direct evidence for the irreversible binding of ethinyl estradiol (EE) - an estrogenic steroid molecule also containing an ethynyl functional group - to an addition cure silicone elastomer. By preparing silicone elastomer samples containing ¹³C-labelled EE, signals in the NMR spectra could readily be assigned to both the free and bound EE. Additional depolymerisation studies, performed on an addition cure silicone elastomer system from which the unbound EE fraction was completely extracted, further confirmed the presence of bound EE through the formation of coloured reaction mixtures resulting from the reaction of bound EE and trifluoroacetic acid (TFA). These methods will be particularly useful in the ongoing development of new steroid-releasing silicone drug delivery devices, including various vaginal ring devices for contraception, HIV prevention and multipurpose prevention technology applications.

Clinically advancing and promising polymer-based therapeutics

In this review article, we will examine the history of polymers and their evolution from provisional World War II materials to medical therapeutics. To provide a comprehensive look at the current state of polymer-based therapeutics, we will classify technologies according to targeted areas of interest, including central nervous system-based and intraocular-, gastrointestinal-, cardiovascular-, dermal-, reproductive-, skeletal-, and neoplastic-based systems. Within each of these areas, we will consider several examples of novel, clinically available polymer-based therapeutics; in addition, this review will also include a discussion of developing therapies, ranging from the in vivo to clinical trial stage, for each targeted area of treatment. Finally, we will emphasize areas of patient care in need of more effective, accessible, and targeted treatment approaches where polymer-based therapeutics may offer potential solutions.

Matrix and reservoir-type multipurpose vaginal rings for controlled release of dapivirine and levonorgestrel

A matrix-type silicone elastomer vaginal ring providing 28-day continuous release of dapivirine (DPV) - a lead candidate human immunodeficiency virus type 1 (HIV-1) microbicide compound - has recently demonstrated moderate levels of protection in two Phase III clinical studies. Here, next-generation matrix and reservoir-type silicone elastomer vaginal rings are reported for the first time offering simultaneous and continuous in vitro release of DPV and the contraceptive progestin levonorgestrel (LNG) over a period of between 60 and 180days. For matrix-type vaginal rings comprising initial drug loadings of 100, 150 or 200mg DPV and 0, 16 or 32mg LNG, Day 1 daily DPV release values were between 4132 and 6113μg while Day 60 values ranged from 284 to 454μg. Daily LNG release ranged from 129 to 684μg on Day 1 and 2-91μg on Day 60. Core-type rings comprising one or two drug-loaded cores provided extended duration of in vitro release out to 180days, and maintained daily drug release rates within much narrower windows (either 75-131μg/day or 37-66μg/day for DPV, and either 96-150μg/day or 37-57μg/day for LNG, depending on core ring configuration and ignoring initial lag release effect for LNG) compared with matrix-type rings. The data support the continued development of these devices as multi-purpose prevention technologies (MPTs) for HIV prevention and long-acting contraception.

Engineering a segmented dual-reservoir polyurethane intravaginal ring for simultaneous prevention of HIV transmission and unwanted pregnancy

The HIV/AIDS pandemic and its impact on women prompt the investigation of prevention strategies to interrupt sexual transmission of HIV. Long-acting drug delivery systems that simultaneously protect womenfrom sexual transmission of HIV and unwanted pregnancy could be important tools in combating the pandemic. We describe the design, in silico, in vitro and in vivo evaluation of a dual-reservoir intravaginal ring that delivers the HIV-1 reverse transcriptase inhibitor tenofovir and the contraceptive levonorgestrel for 90 days. Two polyether urethanes with two different hard segment volume fractions were used to make coaxial extruded reservoir segments with a 100 µm thick rate controlling membrane and a diameter of 5.5 mm that contain 1.3 wt% levonorgestrel. A new mechanistic diffusion model accurately described the levonorgestrel burst release in early time points and pseudo-steady state behavior at later time points. As previously described, tenofovir was formulated as a glycerol paste and filled into a hydrophilic polyurethane, hollow tube reservoir that was melt-sealed by induction welding. These tenofovir-eluting segments and 2 cm long coaxially extruded levonorgestrel eluting segments were joined by induction welding to form rings that released an average of 7.5 mg tenofovir and 21 µg levonorgestrel per day in vitro for 90 days. Levonorgestrel segments placed intravaginally in rabbits resulted in sustained, dose-dependent levels of levonorgestrel in plasma and cervical tissue for 90 days. Polyurethane caps placed between segments successfully prevented diffusion of levonorgestrel into the tenofovir-releasing segment during storage.Hydrated rings endured between 152 N and 354 N tensile load before failure during uniaxial extension testing. In summary, this system represents a significant advance in vaginal drug delivery technology, and is the first in a new class of long-acting multipurpose prevention drug delivery systems.

Multipurpose prevention technologies: products in development

Multipurpose prevention technologies (MPTs) are broadly defined as products capable of simultaneously addressing multiple sexual and reproductive health needs including unintended pregnancy, STIs including HIV-1, and other reproductive tract infections. MPTs have been discussed for a few decades but little product development has occurred. With the recent proof-of-concept that a topically applied antiretroviral (ARV) can effectively reduce sexual transmission of HIV-1 (tenofovir 1% gel) the impetus to develop MPTs is gaining momentum. Products currently in development are broadly categorized as either long-acting or on-demand. Long-acting MPTs include intravaginal rings (IVRs) and long-acting injectable products. Several IVR MPTs are under development including one designed to release tenofovir to prevent transmission of HIV-1 and levonorgestrel (LNG) to prevent unintended pregnancy over a 90-day period. Another MPT IVR under development is designed to release the ARV dapivirine and LNG for 2 months. Long-acting injectable pre-exposure prophylaxis (PrEP) formulations of rilpivirine (TMC278) and GSK1265744 have entered clinical evaluation and could form the basis of long-acting injectable products for HIV-1 prevention and prevention of unintended pregnancy. On-demand products include TFV 1% gel (HIV-1/HSV-2 prevention), a zinc/carrageenan zinc gel (HIV-1/HSV-2 prevention), and the SILCS diaphragm administered with TFV 1% gel. Significant technical, funding, and regulatory hurdles must be overcome to develop most MPTs; however, the significant reproductive health benefits to many women around the world should provide motivation to overcome these hurdles. This article is based on a presentation at the "Product Development Workshop 2013: HIV and Multipurpose Prevention Technologies", held in Arlington, Virginia on February 21-22, 2013. It forms part of a special supplement to Antiviral Research.

Pain and bleeding pattern related to levonorgestrel intrauterine system (LNG-IUS) insertion

OBJECTIVE

To investigate whether the pattern or pain or bleeding during levonorgestrel intrauterine system (LNG-IUS) insertion and in the first 6 weeks thereafter is altered by LNG-IUS malposition.

STUDY DESIGN

Prospective cohort of 413 women undergoing LNG-IUS insertion or replacement. A first questionnaire on pain perception was completed by the women immediately after insertion. In a second questionnaire the women were asked to record pain in the 3 days following insertion and both pain and bleeding from 4 to 6 weeks after insertion. Six weeks after insertion a 2D- and 3D-ultrasound examination was performed to evaluate the position of the LNG-IUS and of the uterus.

RESULTS

Parity was inversely related to pain at insertion, in the first 3 days and at 4-6 weeks. LNG-IUS insertion was less painful in the postpartum period. Women who had had a LNG-IUS as prior contraceptive method reported a higher percentage of amenorrhea at 4-6 weeks. The position of the LNG-IUS or of the uterus did not influence the pain scores or the bleeding pattern. The fact that the LNG-IUS arms appeared embedded in the uterine wall on coronal 3D-volume reconstruction did not influence pain or the bleeding pattern.

CONCLUSIONS

Because neither pain nor bleeding is a reliable predictor of LNG-IUS position, we suggest an ultrasound examination to confirm correct LNG-IUS placement in all patients at about 6 weeks after insertion.

The levonorgestrel-releasing intrauterine system: its effect on the number of hysterectomies performed in perimenopausal women with uterine fibroids

This prospective observational study was designed to determine the percentage of hysterectomies avoided following insertion of a levonorgestrel-releasing intrauterine system (LNG-IUS) in perimenopausal women with uterine fibroids and a prior indication for surgery. The study also compared the progress of patients using the LNG-IUS with those submitted to hysterectomy, with particular emphasis on the patient's satisfaction with treatment. Sixty perimenopausal patients with uterine fibroids and excessive bleeding referred for hysterectomy were included. After counseling on the possibility of non-surgical treatment, 39 patients opted to use an LNG-IUS while 21 opted for hysterectomy. Continuation of LNG-IUS use and the patient's satisfaction with the chosen procedure were assessed. A secondary analysis evaluated hemoglobin levels, clinical complications, bleeding patterns and uterine volume at ultrasonography over time. After 24 months of follow-up, four of the patients who had opted to use an LNG-IUS were submitted to surgery, while 35 continued using the device, thus avoiding hysterectomy in 89.5% of cases. LNG-IUS users were more satisfied with treatment (p = 0.02) compared to those submitted to hysterectomy. In conclusion, the use of the LNG-IUS enables the number of hysterectomies to be reduced in women with uterine fibroids and is associated with greater satisfaction compared to surgical treatment.

Role of the levonorgestrel intrauterine system in effective contraception

Norgestrel, a synthetic progestin chemically derived from 19-nortestosterone, is six times more potent than progesterone, with variable binding affinity to various steroid receptors. The levonorgestrel-releasing intrauterine system (LNG IUS) provides a long-acting, highly effective, and reversible form of contraception, with a pearl index of 0.18 per 100 women-years. The locally released hormone leads to endometrial concentrations that are 200-800 times those found after daily oral use and a plasma level that is lower than that with other forms of levonorgestrel-containing contraception. The contraceptive effect of the LNG IUS is achieved mainly through its local suppressive effect on the endometrium, leading to endometrial thinning, glandular atrophy, and stromal decidualization without affecting ovulation. The LNG IUS is generally well tolerated. The main side effects are related to its androgenic activity, which is usually mild and transient, resolving after the first few months. Menstrual abnormalities are also common but well tolerated, and even become desirable (eg, amenorrhea, hypomenorrhea, and oligomenorrhea) with proper counseling of the patient during the choice of the method of contraception. The satisfaction rates after 3 years of insertion are high, reaching between 77% and 94%. The local effect of the LNG IUS on the endometrium and low rates of systemic adverse effects have led to its use in other conditions rather than contraception, as for the treatment of endometrial hyperplasia, benign menorrhagia, endometriosis, adenomyosis, and uterine fibroids.

Effects of the levonorgestrel-releasing intrauterine system plus estrogen therapy in perimenopausal and postmenopausal women: systematic review and meta-analysis

OBJECTIVE

The objective of this study was to compare the effects of the levonorgestrel-releasing intrauterine system (LNG-IUS) with those of systemic progestogen in perimenopausal and postmenopausal women taking systemic estrogen therapy (ET).

METHODS

We searched Medline (August 8, 2009), Embase (August 8, 2009), the Cochrane Central Register of Controlled Trials on the Cochrane Library Issue 3 (2009), the MetaRegister of Controlled Trials, and the reference lists of articles for relevant trials. Randomized controlled studies of LNG-IUS versus systemic progestogen in perimenopausal and postmenopausal women taking ET were included in the review. Two reviewers abstracted the trials independently. Any disagreement was resolved through discussion with the third reviewer. For dichotomous outcomes, a Peto odds ratio was calculated. For continuous outcomes, nonskewed data from valid scales were synthesized using a weighted mean difference or a standardized mean difference.

RESULTS

Six trials with a total of 518 participants were included. The methodological limitation was an attrition bias. In perimenopausal and postmenopausal women taking ET, the incidence of a proliferative endometrium was comparable between the use of systemic progestogen and LNG-IUS, except for sequential medroxyprogesterone acetate, which had a higher incidence of proliferative endometrium. Descriptive data synthesis showed that ET combined with either LNG-IUS or systemic progestogen effectively relieved climacteric symptoms. Vaginal bleeding and spotting were common in the LNG-IUS group for the first 3 to 6 months of use. The discontinuation rate was not different. There was insufficient evidence to draw any conclusions about the other outcomes.

CONCLUSIONS

The LNG-IUS was more effective than sequential medroxyprogesterone acetate but was comparable with other systemic progestogen regimens for endometrial protection in perimenopausal and postmenopausal women taking ET.

Acceptability of the levonorgestrel intrauterine system in the long-term treatment of heavy menstrual bleeding: how many women choose to use a second device?

OBJECTIVE

To assess the acceptability of the levonorgestrel-releasing intrauterine system (LNG-IUS, Mirena®) in the long-term treatment of heavy menstrual bleeding.

STUDY DESIGN

Retrospective study of all consecutive women who had a LNG-IUS inserted for control of idiopathic heavy menstrual bleeding between January 2000 and December 2003. Duration of use, reasons for early removal, number of devices removed after 5 years of use, and number of women who decided to use a second LNG-IUS were assessed.

RESULTS

Of a total of 216 devices inserted, 129 (59.7%) were removed after 5 years of use, 68 (31.5%) were removed anytime before the completion of 5 years, and the remaining 19 (8.8%) patients were lost to follow-up. In 32 of the 68 cases (47.1%) with early removal of the LNG-IUS, the main reason for discontinuation was the appearance of the menopause. After the 5-year effective lifetime of the LNG-IUS, 51 of the 129 women (39.5%) chose to have a second device inserted. Of the 78 women who completed the 5-year treatment period and did not decide to use the LNG-IUS again, 71 (91%) had reached the menopause.

CONCLUSION

The LNG-IUS was well accepted by women with idiopathic heavy menstrual bleeding as shown by 39.5% of users (or 87.9% if menopausal women are excluded) deciding to use a second device when the first LNG-IUS expired after 5 years of use.