Effect of tissue microenvironment on fibrous capsule formation to biomaterial-coated implants.

Within tissue exposed to the systemic immune system, lymphocytes and fibroblasts act against biomaterials via the development of a fibrous capsule, known as the foreign body reaction (FBR). Inspired by the natural tolerance that the uterine cavity has to foreign bodies, our study explores the role of microenvironment across classical (subcutaneous) and immune privileged (uterine) tissues in the development of the FBR. As a model biomaterial, we used electrospun fibers loaded with sclerosing agents to provoke scar tissue growth. Additionally, we integrated these materials onto an intrauterine device as a platform for intrauterine biomaterial studies. Polyester materials in vitro achieved drug release up to 10 days, greater pro-inflammatory and pro-healing cytokine expression, and the addition of gelatin enabled greater fibroblast attachment. We observed the materials that induced the greatest FBR in the mouse, had no effect when inserted at the utero-tubal junction of non-human primates. These results suggest that the FBR varies across different tissue microenvironments, and a dampened fibrotic response exists in the uterine cavity, possibly due to immune privilege. Further study of immune privileged tissue factors on biomaterials could broaden our understanding of the FBR and inform new methods for achieving biocompatibility in vivo.

Efficacy, Safety, and Tolerability of a New Low-Dose Copper and Nitinol Intrauterine Device: Phase 2 Data to 36 Months.

OBJECTIVE: To assess in parous and nulliparous women, the efficacy, safety, and tolerability of a new, low-dose copper (175 mm) intrauterine contraceptive with a flexible nitinol frame provided in a preloaded applicator. METHODS: Institutional review boards at 12 U.S. sites approved this commercially funded project. Patients met standard inclusion and exclusion criteria for a copper-based intrauterine device (IUD), generally consistent with the Centers for Disease Control and Prevention's U.S. Medical Eligibility Criteria for Contraceptive Use, 2016. Intrauterine device placement occurred at any day in the eligible patient's menstrual cycle after assuring she was not pregnant. The primary outcome measure assessed efficacy (measured by the Pearl Index) in this 1-year study with a 2-year extension. Secondary outcomes included placement success, ease of placement, safety as measured by adverse events, and tolerability assessed by discontinuation rate and bleeding and spotting patterns. RESULTS: A total of 286 women provided 5,640 cycles evaluable for pregnancy. Patients averaged 27.1 years of age. Nulliparous women represented 60.8% of the patients. Over 36 months of observation, we identified two pregnancies (Pearl Index 0.46 [95% CI 0.06-1.67]) and 10 serious adverse events; none were study-related. Successful placement occurred in 283 participants (99.0%). Median (range) continuation times were 2.7 years (0-3.4). We identified five expulsions (1.8%), zero uterine perforations, and one report of pelvic inflammatory disease. Adverse events prompted 30 women (10.6%) to discontinue early in the first year of use with 23 (8.1%) discontinuing for issues of bleeding, pain, or both. Altogether, 107 (37.8%) completed 36 months of device use. Mean bleeding days per cycle decreased from 7.6 in cycle 1 to 5.2 in cycle 13. CONCLUSION: The novel, low-dose copper and nitinol IUD demonstrated high efficacy and safety in this phase 2 U.S. Food and Drug Administration trial and warrants further expanded study in a phase 3 clinical trial. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02446821. FUNDING SOURCE: Sebela Pharmaceuticals, Inc.

A randomized comparison of a novel nitinol-frame low-dose-copper intrauterine contraceptive and a copper T380S intrauterine contraceptive.

OBJECTIVE: We sought to compare VeraCept (VC175), a novel nitinol intrauterine contraceptive (IUC) with 175 square-mm of copper surface area, to a copper T380S IUC. STUDY DESIGN: We enrolled parous women into a randomized subject-blinded comparison of VC175 and a copper T380S in a 2:1 fashion at a single clinic. The primary outcomes were total adverse events and continuation at 12 months. We also examined pain on insertion, ease of placement, expulsion, tolerability and pregnancy. Subjective ratings were on a 5-point Likert scale (0, no pain to 5, worst pain). We followed subjects through 24-month follow-up. RESULTS: We enrolled 300 women with 199 randomized to VC175 and 101 to the T380S. Insertion was successful in 198 subjects for VC175 and 100 for the T380S. Mean age was 25 years (range 18, 41), and median parity was 2 (range 1, 8), with 39% having only had Cesarean deliveries. No subjects developed clinical infection or reported serious adverse events. In the VC175 and T380S groups, mean pain at insertion was 1.4 and 2.4, respectively (p<.01). At the 12-month primary endpoint for VC175 and T380S, respectively, continuation was 84% and 68% (p<.002) with expulsions in 5.0% and 12.0% (p<.05) and removal for pain/bleeding in 3.5% and 17.0% (p<.01). At the 24-month visit for VC175 and T380S, respectively, continuation was 77% and 62% (p<.02 by log-rank). One ectopic pregnancy was identified at the 12-month follow-up in a VC175 user. No other pregnancies were diagnosed. With 297.3 and 132.4 woman-years, pregnancy rates were 0.3 and 0.0 per 100 woman-years for VC175 and T380S, respectively. CONCLUSIONS: VC175 resulted in less pain at insertion, fewer expulsions and higher total continuation than the T380S, with similar contraceptive efficacy. IMPLICATIONS: VC175 is a promising new intrauterine copper contraceptive on a nitinol frame that warrants further clinical trials.