Exploring the safety and tolerability of maraviroc-containing regimens for preventing HIV infection in women
Despite remarkable scientific progress, HIV remains a pressing global health challenge that disproportionately affects women. In 2023 alone, approximately 1.3 million people worldwide acquired HIV, with women and girls representing a significant portion of new infections, particularly in vulnerable regions.
This stark reality underscores an urgent need for effective prevention strategies that women can control. While daily oral pre-exposure prophylaxis (PrEP) has transformed HIV prevention, concerns about long-term toxicity, adherence challenges, and the simple desire for more options have driven scientists to investigate alternative regimens.
Among these investigational approaches, maraviroc-containing regimens have emerged as a promising candidate, offering a unique mechanism of action and potentially favorable safety profile. This article explores the science behind this innovative approach, focusing specifically on what the research reveals about its safety and tolerability for women.
Women represent over 50% of people living with HIV worldwide
Maraviroc studied as PrEP since 2020 with promising results
To appreciate maraviroc's potential for HIV prevention, one must first understand its unique mechanism of action. Unlike most antiretroviral drugs that attack the virus itself after it has entered cells, maraviroc takes a different approach—it blocks the doorway HIV uses to enter our immune cells.
This elegant mechanism has made maraviroc an established treatment for HIV infection since 2007, but researchers are now exploring its potential for prevention.
In 2020, a transformative study published in Antimicrobial Agents and Chemotherapy provided crucial insights into maraviroc's potential as PrEP specifically for women 1 . This research employed a translational approach, combining drug concentration measurements in actual tissues from volunteers with sophisticated computer modeling to predict efficacy across different dosing scenarios.
The study enrolled 24 healthy women and measured maraviroc concentrations in various body compartments after dosing. Researchers discovered a remarkable finding: maraviroc concentrations were approximately 350 times higher in colorectal tissue compared to the female genital tract (FGT). This distribution pattern has profound implications for protection, as HIV exposure occurs primarily at these mucosal surfaces.
Using Monte Carlo simulations—a sophisticated statistical technique that models probability—the research team predicted how different dosing strategies would protect against HIV infection in these vulnerable tissues.
| Dosing Frequency | Female Genital Tract Protection | Colorectal Tissue Protection |
|---|---|---|
| 1 dose/week | Low | 99% |
| 4 doses/week | Moderate | >99% |
| 7 doses/week | 63% | >99% |
Perhaps the most encouraging finding was that maraviroc combinations with other antiretrovirals significantly improved protection predictions. When maraviroc was paired with tenofovir (5 doses/week) or emtricitabine (3 doses/week), protection in the female genital tract increased to over 90% of the simulated population 1 . This synergy suggests that maraviroc may be most effective for women when used as part of a multi-drug prevention strategy rather than as a single agent.
Maraviroc alone provides 63% protection in female genital tract with daily dosing
Maraviroc with other antiretrovirals increases protection to over 90%
Maraviroc has been used as part of HIV treatment regimens since 2007, providing substantial long-term safety data. A 10-year retrospective study published in the International Journal of Antimicrobial Agents followed 111 patients using maraviroc and found it generally well-tolerated over extended periods 6 . The research documented a continuous increase in CD4+ T-cell counts—a key marker of immune health—over nine years of follow-up, suggesting not just safety but potential immunological benefits.
According to the Mayo Clinic and prescription information, the most commonly reported side effects of maraviroc in clinical trials included 4 7 :
These side effects were typically mild to moderate in severity and rarely led to discontinuation of treatment. The dizziness reported was often associated with postural hypotension (a drop in blood pressure when standing up quickly), which can usually be managed by standing up slowly and maintaining adequate hydration.
While generally well-tolerated, maraviroc does carry some important safety considerations that women should be aware of:
There have been reports of liver toxicity, which may be preceded by severe rash or systemic allergic reactions. Monitoring liver enzymes is recommended, particularly for women with pre-existing liver conditions or hepatitis B or C co-infection 7 .
Some studies have noted more cardiovascular events in treatment-experienced patients receiving maraviroc, though the absolute risk remains low 7 .
Maraviroc is metabolized by the liver enzyme CYP3A, so it interacts with many other medications. Dose adjustments are necessary when taken with certain drugs like some antibiotics, antifungals, and seizure medications 4 .
Potentially serious skin reactions including Stevens-Johnson syndrome have been reported, though these are rare 8 .
| Safety Concern | Frequency | Monitoring/Management |
|---|---|---|
| Hepatotoxicity | Rare | Monitor liver enzymes before and during treatment |
| Dizziness | Common | Rise slowly from sitting/lying position |
| Skin reactions | Rare | Discontinue medication if severe rash develops |
| Cardiovascular events | Uncommon | Monitor blood pressure and cardiovascular symptoms |
For women considering maraviroc for HIV prevention, several special considerations apply:
Limited data exists on maraviroc use during pregnancy. Women who are pregnant or planning pregnancy should discuss potential risks and benefits with their healthcare provider 7 .
The Centers for Disease Control and Prevention recommend that women with HIV in the United States should not breastfeed. The potential for maraviroc to transfer into breast milk and affect the infant is not well-studied 8 .
Some research suggests that the needs of women with HIV "extend beyond antiretroviral therapy" to include comprehensive care for co-infections like HPV and other health conditions .
The evidence supporting maraviroc for HIV prevention in women, while promising, highlights several areas requiring further research. Future studies need to focus on:
Developing strategies that balance efficacy with convenience and adherence
Understanding influences on drug concentrations in the female genital tract
Evaluating safety specifically in healthy women using the drug for prevention
Developing long-acting injectables or topical gels for better tissue concentrations
The International Workshop on Women & HIV has emphasized that "injectable antiretroviral agents for treatment and prevention are adding an important choice for women," while acknowledging that "challenges regarding access need to be addressed" .
This reflects the broader recognition that effective prevention requires not just scientific innovation but also practical implementation strategies that address real-world barriers.
Research into maraviroc-containing regimens for preventing HIV in women represents an exciting frontier in the ongoing battle against this pandemic. The evidence to date suggests that maraviroc offers a favorable safety profile with generally mild side effects, though it requires appropriate monitoring for rare but serious potential complications. Its unique mechanism of action provides a valuable alternative to currently available PrEP options, particularly when used in combination with other antiretrovirals.
While maraviroc is not yet approved specifically for HIV prevention, the scientific foundation is being built through rigorous research that recognizes and addresses the unique physiological considerations of women. As the field advances, maraviroc may well become an important addition to the increasingly diverse toolkit of HIV prevention options—giving women more choices to protect their health according to their individual needs, preferences, and circumstances.
The journey from treatment to prevention continues to illustrate a powerful paradigm in modern medicine: sometimes, the same key that helps unlock one door may help close another.
References will be listed here in the final version.