Selective Estrogen Receptor Modulators to Enhance the Efficacy of Viral Reactivation With Histone Deacetylase Inhibitors

The selective estrogen receptor modulator (SERM) tamoxifen may enhance the ability of the histone deacetylase inhibitor (HDACi) vorinostat to reverse HIV-1 latency. This study evaluated the safety of tamoxifen therapy combined with vorinostat and the effectiveness of this combination on latent virus reactivation in HIV-1 infected post-menopausal women with virologic suppression on antiretroviral therapy, when compared to vorinostat alone.

The study was conducted in two steps. During Step 1, the study enrolled women with HIV into two groups. Arm A received tamoxifen daily for 38 days, plus a single dose of vorinostat on Days 35 and 38. Arm B had a 38-day observation period with no tamoxifen, plus a single dose of vorinostat on Days 35 and 38. All participants continued to take ART drugs prescribed by their doctors. ART drugs were not be provided by the study.

Study visits during Step 1 occurred at Days 0, 28, 35, 38, 45, and 65. Study visits could include physical examinations, blood collection, electrocardiograms, and adherence assessments.

During Step 2, all participants were followed for 240 additional weeks for annual long-term safety follow-up. These visits were conducted by phone and collected information from participants on vital status and any new cancer diagnoses.

Step 1 and Step 2 have been completed and this results submission pertains to both.

Inclusion criteria

• HIV-1 infection
• Postmenopausal at study entry with agreement not to participate in assisted reproductive technology in the future.
• CD4+ cell count greater than 300 cells/uL obtained within 90 days prior to study entry.
• Continuous antiretroviral therapy (ART) for at least 2 years prior to enrollment with no known interruption in therapy for greater than 7 days within 90 days prior to study entry.
• Plasma HIV-1 RNA level of less than 20 copies/mL obtained by Roche HIV-1 viral load assay or less than 40 copies/mL obtained by the Abbott assay, within 90 days prior to study entry.
• Ability and willingness of potential participant to provide written informed consent.

Exclusion criteria

• History of venous thromboembolism.
• History of stroke.
• Known history of hypercoagulable state.
• Tobacco smoking or e-cigarette use within 90 days prior to study entry.
• History of any malignancy requiring systemic chemotherapy or systemic immunotherapy.
• History of endometrial or breast cancer or known genetic testing with BRCA positive results indicating an increased risk for breast and ovarian cancer.
• Use of immunomodulators (e.g., interleukins, interferons, cyclosporine), HIV vaccine, or investigational therapy within 60 days prior to study entry.
• Any systemic hormonal therapy defined as oral or injectable contraceptives, estrogen and combined estrogen-progesterone replacement therapy in the prior 12 months, or a hormone containing intrauterine device (IUD) within 6 months prior to study entry.
• Known allergy/sensitivity or any hypersensitivity to components of study drugs or their formulations.