Treatment-experienced HIV patients in the UK now have access to a new weapon against the disease, following yesterday’s launch of Pfizer’s first-in-class therapy Celsentri.

According to Pfizer, Celsentri (maraviroc) is the first new oral class of HIV therapy in more than a decade, and represents “a significant innovation in the treatment of HIV infection”, and Professor Margaret Johnson, Clinical Director HIV/AIDS Services, Royal Free Hospital, London and Chair of the British HIV Association, said its introduction “is incredibly important for the HIV community”.

Discovered and developed by Pfizer scientists in Sandwich, Kent, the drug is the first in a new class of HIV medicines known as CCR5 antagonists - which are part of a wider group known as entry inhibitors - and was given a green light by European regulators for treatment-experienced patients in September.

What makes the drug special is its unique mode of action; Celsentri focuses on the body rather than the actual virus, barring its entry into human immune (CD4) cells and thereby preventing HIV replication. All other HIV medicines currently on the market work on the HIV virus after it has infected immune cells, so the launch of Celsentri will allow clinicians to architect treatment regimens focused on a two-pronged attack both inside and outside the cell, Pfizer said.

Clinical evidence
The drug’s approval was based on results from large-scale clinical trials that demonstrated its ability to both cut the amount of virus in the blood stream to “undetectable levels” and boost the number of immune CD4 cells when added to standard therapy.

Specifically, pooled results from the Phase III trials MOTIVATE 1 and 2 showed that around twice the percentage of patients who were treated with Celsentri 300mg twice daily plus optimised background therapy achieved undetectable viral loads compared with those taking a placebo and OBT (45.5% versus 16.7%, respectively). Pfizer is also currently assessing the drug’s potential in a clinical trial of treatment-naive patients which, if successful could sustantially expand its market.

Celsentri will be available on the NHS at a cost of £18.37 per day per patient, which is in line with existing HIV treatments, a company spokesperson told PharmaTimes UK News. She went on to say that HIV therapies have not traditionally been reviewed by the country’s cost-effectiveness body, the National Institute for Health and Clinical Excellence, and that Pfizer is not aware of any such plans to assess the drug.