A Phase 1 Clinical Trial to Assess the Safety and Pharmacokinetics of a Tenofovir Alafenamide/Elvitegravir Insert Administered Rectally for HIV Prevention

BACKGROUND

On-demand topical products could be an important tool for HIV prevention. We evaluated the safety, pharmacokinetics, and ex vivo pharmacodynamics of a tenofovir alafenamide/elvitegravir (TAF/EVG; 16 mg/20 mg) insert administered rectally.

METHODS

MTN-039 was a Phase 1, open-label, single-arm, 2-dose study. Blood, rectal fluid (RF), and rectal tissue (RT) were collected over 72 hours (hr) following rectal administration of one and two TAF/EVG inserts for each participant. ClinicalTrials.gov Identifier: NCT04047420.

RESULTS

TAF/EVG inserts were safe and well tolerated. EVG and tenofovir (TFV) were detected in blood plasma at low concentrations: median peak concentrations after 2 inserts were EVG 2.4 ng/mL and TFV 4.4 ng/mL. RT EVG peaked at 2-hr (median 2 inserts= 9 ng/mg) but declined to BLQ in the majority of samples at 24-hr, whereas TFV-DP remained high >2,000 fmol/million cells for 72-hr with 2 inserts. Compared to baseline, median cumulative log10 HIV p24 antigen of ex vivo rectal tissue HIV infection was reduced at each timepoint for both 1 and 2 inserts (p<0.065 and p<0.039, respectively).

DISCUSSION

Rectal administration of TAF/EVG inserts achieved high rectal tissue concentrations of EVG and TFV-DP with low systemic drug exposure and demonstrable ex vivo inhibition of HIV infection for 72 hours.

COVID-19 booster vaccination during pregnancy enhances maternal binding and neutralizing antibody responses and transplacental antibody transfer to the newborn

The immune response to COVID-19 booster vaccinations during pregnancy for mothers and their newborns and the functional response of vaccine-induced antibodies against Omicron variants are not well characterized. We conducted a prospective, multicenter cohort study of participants vaccinated during pregnancy with primary or booster mRNA COVID-19 vaccines from July 2021 to January 2022 at 9 academic sites. We determined SARS-CoV-2 binding and live virus and pseudovirus neutralizing antibody (nAb) titers pre- and post-vaccination, and at delivery for both maternal and infant participants. Immune responses to ancestral and Omicron BA.1 SARS-CoV-2 strains were compared between primary and booster vaccine recipients in maternal sera at delivery and in cord blood, after adjusting for days since last vaccination. A total of 240 participants received either Pfizer or Moderna mRNA vaccine during pregnancy (primary 2-dose series: 167; booster dose: 73). Booster vaccination resulted in significantly higher binding and nAb titers, including to the Omicron BA.1 variant, in maternal serum at delivery and in cord blood compared to a primary 2-dose series (range 0.44-0.88 log10 higher, p < 0.0001 for all comparisons). Live virus nAb to Omicron BA.1 were present at delivery in 9 % (GMT ID50 12.7) of Pfizer and 22 % (GMT ID50 14.7) of Moderna primary series recipients, and in 73 % (GMT ID50 60.2) of mRNA boosted participants (p < 0.0001), although titers were significantly lower than to the D614G strain. Transplacental antibody transfer was efficient for all regimens with median transfer ratio range: 1.55-1.77 for IgG, 1.00-1.78 for live virus nAb and 1.79-2.36 for pseudovirus nAb. COVID-19 mRNA vaccination during pregnancy elicited robust immune responses in mothers and efficient transplacental antibody transfer to the newborn. A booster dose during pregnancy significantly increased maternal and cord blood binding and neutralizing antibody levels, including against Omicron BA.1. Findings support the use of a booster dose of COVID-19 vaccine during pregnancy.

Impact of Sex on the Pharmacokinetics and Pharmacodynamics of 1% Tenofovir Gel

BACKGROUND

Tenofovir (TFV) gel partially protected against human immunodeficiency virus (HIV) in one but not subsequent trials. The disappointing results were attributed largely to poor adherence. However, timing of gel application relative to sex may impact pharmacokinetics and contribute to outcomes. Thus, we conducted a single-dose pharmacokinetic study of TFV gel applied 1 or 24 hours before or 1 hour before and 1 hour after (BAT) sex and compared results with dosing without sex.

METHODS

Twenty-four couples were enrolled; cervicovaginal lavage (CVL) and tissue were collected 2 hours after sex with matching timed collections at no sex visits and assayed for drug concentrations and CVL anti-HIV activity.

RESULTS

Compared with dosing without sex, median TFV concentrations after sex decreased 72% and 78% (P < .001) in CVL, 75% and 71% (P < .001) in vaginal tissue, and 75% (P = .06) and 55% (P < .001) in cervical tissue with -1 hour and -24 hour dosing, respectively. Median concentration of TFV-diphosphate also decreased significantly in cervical tissue with -1 hour, dosing. BAT dosing resulted in drug levels at least as great as those in the absence of sex. Percent inhibition of HIV infection by post-coital CVL increased significantly from median (interquartile range) of 55% (54%) in the absence of gel to 99% (7%), 77% (57%), and 100% (0.4%) with -1 hour, -24 hour, or BAT dosing, respectively, and correlated significantly with drug concentration.

CONCLUSIONS

Timing of TFV gel application relative to sex significantly impacts drug levels. BAT dosing or sustained delivery may be optimal for preexposure prophylaxis.

Effects of partnership change on microbicide gel adherence in a clinical trial (HPTN 035)

Use of HIV prevention methods may vary for women by types of sexual partners. In a microbicide safety and effectiveness trial (HPTN 035) differences in adherence to a microbicide study gel were compared between women with new versus ongoing partnerships over time. 1,757 women in the three HPTN 035 trial's arms completed the Follow-up Partner Status (FPS) questionnaire at their last study visit. Women married at baseline were asked if they had the same husband, new husband or new partner. Unmarried women were asked if they had changed partners or married. Self-reported gel adherence during the last sex act was compared at each quarterly visit between women with ongoing versus new partners. High gel adherence was compared with low gel adherence (85-100 vs. <85 % of last vaginal sex acts reported with gel use, respectively) in multivariable models to assess associations with partner change. Overall 7 % of women (n = 123) reported a new partner and 41 % (51) of those reported a new husband. Median gel adherence was reported to be 100 % in women with ongoing partners and 75 % for women with new partners (p < 0.001). In women reporting no gel use in their last sex act, only 12.5 % of the women with a new partner and none of those with an ongoing partner reported using condoms (p < 0.001). Fewer women with new partners reported using both the gel and condom during the last sex act as compared to women with ongoing partners (median 50 vs. 71.4 %, p < 0.001). After adjusting for age, site, education level, and sexual frequency, women with ongoing partners were more likely to report high gel adherence than those with new partners (AOR 2.5, 95 % CI 1.6, 3.9). This pattern persisted when gel use over time was compared between women with new versus ongoing partners. In the HPTN 035 trial, women with new partners had higher HIV incidence and reported less gel use and higher condom use. Specific counseling and support are needed to help women use potential HIV prevention methods, including microbicides, when they are changing partners.

Nonoxynol-9 100 mg gel: multi-site safety study from sub-Saharan Africa

OBJECTIVES

To evaluate the safety of 100 mg nonoxynol-9 (N-9) gel, a vaginal microbicide, on the genital mucosa of women from Malawi and Zimbabwe in preparation for a phase III efficacy study.

METHODS

HIV-uninfected women (180) were enrolled and randomized to either N-9 or placebo gel and instructed to insert gel into the vagina twice daily for 14 days. Follow up examinations were conducted at 7 and 14 days.

RESULTS

The number of adverse events in the N-9 gel group was higher than in the placebo group (40% versus 13%; P < 0.01). Reported number of any genital symptoms was significantly higher in the N-9 group (38% N-9, 13% placebo; P = 0.01). The number of total epithelial disruptions was higher in the N-9 group (20% versus 3%; P < 0.01); however, the number of genital ulcers and abrasions in the N-9 group was low (2% and 3%, respectively) and not different from that in the placebo group (1% and 2%, respectively).

CONCLUSIONS

N-9 gel 100 mg caused a significant increase in the rate of genital symptoms and epithelial disruptions compared with placebo. The clinical significance of these epithelial disruptions is unknown. Although these findings alone were not sufficient to cancel the planned phase III study, when considered together with the negative results from the COL-1492 effectiveness trial of 52.5 mg N-9 gel, the decision was made to cancel the planned phase III trial of 100 mg N-9 gel.

Acceptability of a microbicide among women and their partners in a 4-country phase I trial

OBJECTIVES

We analyzed qualitative and quantitative data for 98 HIV-negative, low-risk women in Malawi, Zimbabwe, India, and Thailand who participated in a safety and acceptability study of BufferGel, a vaginal microbicide to determine the across-country acceptability of vaginal microbicides among women and their partners.

METHODS

Quantitative survey data were collected at 7 and 14 days after use among enrolled women, and exit interviews were conducted with women and their partners in separate focus group discussions.

RESULTS

Acceptability was high in all sites (73% of women approved of the microbicide). Women in Africa, where HIV infection rates are highest, were virtually unanimous in their desire for such a product, suggesting that an individual's perception of being at risk for HIV will outweigh concerns about side effects, problems applying a product, or other factors, when products are shown to be efficacious. But men and women reported that use, which was kept secret from an intimate partner, would be difficult and might "break the trust" of a relationship.

CONCLUSIONS

Acceptability research across diverse settings through all stages of microbicide research, development, and post-licensure dissemination can help maximize acceptability and use.

Safety and acceptability of penile application of 2 candidate topical microbicides: BufferGel and PRO 2000 Gel: 3 randomized trials in healthy low-risk men and HIV-positive men

OBJECTIVES

To assess safety and acceptability of penile application of BufferGel (ReProtect, Baltimore, MD) and PRO 2000 Gel (Indevus Pharmaceuticals, Lexington, MA)compared with placebo among low-risk sexually abstinent men and HIV-positive sexually abstinent men.

DESIGN

Seventy-two healthy low-risk men (36 uncircumcised) and 25 HIV-positive men (12 uncircumcised) were enrolled in 3 double-blind, single-center studies as follows: 36 low-risk men in a study of BufferGel and K-Y Jelly (McNeil-PPC, Skillman, NJ) placebo; 36 low-risk men in a study of PRO 2000 Gel and vehicle placebo; and 25 HIV-positive men in a crossover study of BufferGel, PRO 2000 Gel, and K-Y Jelly placebo.

METHODS

Participants applied product to the penis on 7 consecutive nights, kept study diaries, and were then interviewed and examined. Urine was tested for inflammation by leukocyte esterase.

RESULTS

No serious adverse events (AEs) or urethral inflammation was detected. During use of BufferGel, 3 low-risk men (13%) reported 6 AEs and 2 HIV-positive men (8%) reported 3 AEs. During use of PRO 2000 Gel, 4 low-risk men (17%) reported 6 AEs and 1 HIV-positive participant (4%) had 1 AE. AE rates during use of BufferGel and PRO 2000 Gel use were not significantly different from rates observed during placebo. One low-risk man (4%) would object to his partners using BufferGel and 3 (13%) to PRO 2000 Gel. Two HIV-positive men (8%) reported they would object to partners using either BufferGel or PRO 2000 Gel.

CONCLUSIONS

Daily application of BufferGel and PRO 2000 Gel directly to the penis consecutively for 7 days was generally safe and well tolerated among healthy low-risk men and HIV-positive men. These microbicides have acceptable safety profiles to proceed with planned phase 3 vaginal microbicide trials.

Safety and toxicity of nonoxynol-9 gel as a rectal microbicide

BACKGROUND AND OBJECTIVES

Methods of HIV and STD prevention, which can be controlled by the receptive partner, are a high priority for research and development. Studies on the safety of Nonoxynol-9 (N-9) on the vaginal mucosa have yielded conflicting results. No Phase I study has evaluated the effect of N-9 on the rectal mucosa.

GOALS

To assess the safety of 52.5 mg of N-9 in a 1.5-g gel when applied one to four applicators per day to the rectum and penis.

STUDY DESIGN

The study included 25 HIV-negative and 10 HIV-positive, monogamous gay male couples in which each partner was exclusively insertive or receptive while using N-9 gel. Each participant served as his own control during placebo gel use compared to during N-9 gel use. Receptive partners underwent anoscopic examination after 1 week of placebo use and after 2, 5, and 6 weeks of N-9 gel use, with rectal biopsies obtained after 1 week of placebo use and after 5 and 6 weeks of N-9 gel use. Insertive partners had safety monitoring after 1 week of placebo use and after 2, 5, and 6 weeks of N-9.

RESULTS

No rectal ulcers were detected; superficial rectal erosions were noted in two HIV-negative participants. Abnormal or slightly abnormal histologic abnormalities of rectal biopsies were detected in 31 (89%) receptive participants after N-9 gel use compared to 24 (69%) participants after 1 week of placebo gel use. Meatal ulceration, not caused by herpes simplex virus, was detected in one HIV-negative participant.

CONCLUSION

Low-dose N-9 gel was not associated with macroscopic rectal and penile epithelial disruption or inflammation, but histologic abnormalities were commonly observed during N-9 gel as well as during placebo gel use.

Acceptability of a bioadhesive nonoxynol-9 gel delivered by an applicator as a rectal microbicide

BACKGROUND AND OBJECTIVES

Potential rectal microbicides, as an adjunct to condoms for HIV/STD prevention, have not been studied previously.

GOAL OF THIS STUDY

Advantage 24 (1.5 ml of a bioadhesive gel containing 52.5 mg nonoxynol-9 administered by single-use applicator)-under investigation as a vaginal microbicide-was evaluated for acceptability among male couples.

STUDY DESIGN

Twenty-five HIV-negative and 10 HIV-positive male couples participated in a frequency use escalation trial. Diaries and self-administered questionnaires assessed product use, acceptability, sexual behavior, and gastrointestinal and urologic side effects.

RESULTS

Excluding participants who felt no need for an HIV prevention method, 58% said they would use Advantage 24 if approved for rectal use; 69% of receptive users reported rectal fullness and related side effects after insertion of the gel, and 68% reported applicator-related discomfort; 59% of insertive participants found the gel too sticky.

CONCLUSIONS

Acceptability remains inconclusive and warrants further study of redesigned applicators and ways to minimize rectal side effects.

Structural characteristics of immature rat Sertoli cells in vivo and in vitro

The structural properties of pelleted prepubertal Sertoli cells (pre-culture pelleted cells) from 19-day-old rats and of similar cells cultured for 7 days were compared with Sertoli cells from the intact animal (testis tissue from 19- and 26-day-old rats, the in vivo groups). Sertoli cells from freshly isolated pellets and those cultured for 7 days were similar in cell and nuclear volumes to their in vivo counterparts. Cell volumes, organelle volumes, and organelle volume densities of newly isolated Sertoli cells were similar to those of sectioned cells taken from the 19-day-old in vivo group, indicating that the procedure for isolation does not grossly alter Sertoli cells. Mean height of cells cultured for 7 days was significantly lower than that of cells from intact animals at 19 and 26 days of age. In vivo, Sertoli cells of 26-day-old animals displayed increased organelle volumes and organelle surface areas compared with those from 19-day-old animals; volume densities and surface densities remained relatively constant, indicating that in vivo, organelle growth is in proportion to growth of the cell. Most organelle volume and surface densities were not significantly different when 19-day-old in vivo cells and pre-culture pelleted cells were compared. Many organelle volume and surface density values were significantly less in cells grown in culture for 7 days as compared to freshly isolated pelleted cells. After 7 days of culture, most Sertoli cell organelles were significantly less in both volume density and surface density, as compared to the in vivo cell groups (19 or 26 day). This indicates that in vitro the organelles do not develop in proportion to the growth of the cell. After 7 days in culture, the absolute volumes and surface areas of the organelles remained generally unchanged as compared to cells from 19-day-old animals. The data show that Sertoli cells grow in volume in vitro like their in vivo counterparts; however, their subcellular features, although well maintained, do not develop in proportion to the cell. This suggests that short-term cultures are a more ideal system in which to study biochemical responses. Also, cultured prepubertal Sertoli cells are most appropriately used to study prepubertal Sertoli cell function. This is the first study to quantify developmental changes in Sertoli cell structure in vivo as well as to compare them with cellular changes occurring in vitro.