- Weekly injections of CytoDyn's experimental antibody PRO140 cut down the viral load of HIV-1 patients who are resistant to antiretroviral drugs reducing plasma RNA levels below 50 copies/mL in 81% of patients given CytoDyn's drug together with antiretroviral therapy.
- A viral-entry inhibitor that blocks a cellular receptor called CCR5, PRO140 aims to protect healthy T cells from viral infection. Several patients who continued to receive PRO140 in an extension stage of the study have maintained viral load suppression for over two years.
- The Food and Drug Administration has granted a Fast Track Designation to PRO140 and CytoDyn plans to file an application to the regulator for approval of the drug as a combination therapy. A rolling submission is expected to begin as soon as year end.
CytoDyn has had a busy July. Last Thursday, it announced a non-binding letter of intent to acquire CCR5-focused cancer startup ProstaGene, in order to expand its clinical focus to include cancers and immunological indications.
ProstaGene brings drug discovery and screening expertise, along with know-how in prostate cancer diagnostics and therapeutics aimed at blocking cancer metastasis by blocking CCR5, which also plays a role in inflammation.
As it expands into cancer, CytoDyn will continue to advance its clinical programs in HIV and graft-versus-host disease. That said, CytoDyn plans to pursue "partnership opportunities to support all of our development programs," according to company chair Anthony Caracciolo.
Drug resistant HIV patients are, by definition, hard to treat, and targeting that population could serve as a differentiator for the company. CytoDyn reported in February that its combination study with PRO 140 met its primary endpoint in reducing RNA viral load. The data announced Monday are from a subsequent four months of follow-up study.
According to the World Health Organization, levels of HIV drug resistance were around 7% in developing countries until 2010. "Recently, some countries have reported levels at or above 10% amongst those starting HIV treatment, and up to 40% among people re-starting treatment," the WHO said in a 2016 statement.
The cutoff of 50 HIV-1 RNA copies/ml is one of the definitions of undetectable viral load, and this level is associated with durable clinical and immunological benefits, as well as a reduced risk of transmission.