CMV Retinitis: Neglected Opportunistic Disease of the AIDS Pandemic Causing Blindness in Southeast Asia

April 4, 2008
CMV Retinitis: Neglected Opportunistic Disease of the AIDS Pandemic Causing Blindness in Southeast Asia
Treatment to prevent blindness at an

EPICENTER

Thailand 2006 © MSF

A hospital worker divides antiretroviral drugs into containers for children living with HIV.

Cytomegalovirus (CMV) retinitis, a condition that causes blindness in patients with advanced HIV, has long been a neglected disease of the AIDS pandemic, leading to unnecessary cases of blindness, particularly in Southeast Asia. The full scale of the CMV retinitis problem in developing regions is still not known, but a recent paper published in PLoS Medicine, based on pilot studies from various MSF projects, found that CMV retinitis occurred in 23, 27, and 32 percent of patients with advanced HIV in Cambodia, Myanmar, and Thailand, respectively.

Complications from CMV retinitis— most notably blindness—are preventable with screening programs and anti-CMV treatment. However, screening is unfortunately not routinely performed in many places where CMV retinitis is prevalent. The $10,273 price for a four-month course of treatment is prohibitive. The treatment, an oral medicine named valganciclovir produced solely by Hoffman-La Roche, is far too expensive for most of the patients with this disease. A negotiated price of $1,899 for four months of valganciclovir is still too expensive. Lower middle-income countries where CMV is a major problem, such as China and Thailand, are not eligible for this discounted price. Confronting a debilitating disease

Confronting a Debilitating Disease

Dr. David Wilson, former MSF medical coordinator in Thailand, has worked on MSF HIV/AIDS projects throughout Asia. Back when MSF only provided palliative care for HIV/AIDS patients, it was common for very sick patients to go blind and die. In 2000, MSF first began using antiretrovirals (ARVs) to treat HIV/AIDS, and there was great hope that patients would go on to live normal lives, he said. But while ARVs helped restore patients’ health, CMV infection and resulting blindness continued unchecked.

Wilson recalls the very first patient MSF started on ARVs. “I remember her well for a very unfortunate reason,” he says. “Within one month of starting treatment, she became blind from CMV. But since she was on ARV treatment, her health improved. She went on to live a long time, but completely blind.”

CMV poses a threat to a patient’s sight once a person’s immune system is weakened. Irreparable destruction of the entire retina can occur within weeks.

Because CMV leads to blindness in patients with advanced HIV disease, treatment must consist of both CMV treatment for the infection and ARV therapy to restore immune function. If the CMV infection is not treated, it is not uncommon for a patient on ARVs to go blind just as they are becoming healthier.

Patients most susceptible to CMV— those with low CD4 counts who are not being treated for HIV/AIDS—often live in impoverished, rural areas where blindness can have a devastating impact.

“The particular kind of blindness caused by CMV is absolute, total blindness,” Wilson says. “The patient cannot tell the difference between light and dark. Someone who is blind from cataracts, for example, can distinguish some things; they need some help, but often they can manage. Someone with CMV, when everything is totally black, it’s very difficult for them to eat without someone actually feeding them, or to do very much of anything to help themselves.”

CMV is often asymptomatic in its earlier stages and can best be diagnosed through systematic screening of all at-risk patients. The best method to diagnose CMV—retinal examination using an indirect ophthalmoscope on fully dilated pupils—is not a fundamental part of HIV programs in the developing world.

The high cost of valganciclovir poses another major obstacle for patients in resource-poor settings. An alternative treatment using intravenous ganciclovir requires twice-daily injections for two or three weeks, and then daily injections for another two to three months. Another method—intraocular injections of ganciclovir—is invasive and involves a doctor repeatedly jabbing patients with a needle in one or both infected eyes. Although both options are effective, oral valganciclovir therapy remains the least invasive option. Treatment out of reach for many

Treatment Out of Reach for Many

The preferred treatment, valganciclovir, comes in pill form and, unlike intraocular ganciclovir, can also treat potentially fatal forms of CMV that occur outside the eye. Roche of Basel, Switzerland, holds patents for valganciclovir in most countries around the world and is the only producer of the drug. Valganciclovir is marketed almost exclusively as a drug to prevent CMV infection in patients undergoing organ transplants in wealthy and middle income countries, a small but lucrative market.

“This is a classic case of the vicious circle,” said Dr. Tido von Schoen- Angerer, Director of MSF’s Campaign for Access to Essential Medicines. “Because the price of the drug is so high, HIV programs aren’t screening and therefore are not reporting large numbers of CMV patients. But since on paper there are so few patients, bringing down the price of this treatment and ensuring its availability has never been a priority.”

Even though Hoffman-La Roche has proposed a discounted price of $1,899 for least developed countries and sub- Saharan Africa, the offer remains expensive and excludes many countries, such as China and Thailand, where the CMV retinitis is most acute. This has forced difficult compromises. In Thailand, along with local partners, MSF has decided to use the sub-optimal intravenous formulation of ganciclovir, as well as intraocular injections. In China, MSF pays the full price for oral valganciclovir, which at $10,273, costs more than a Chinese economy car.

“We have a strategy to make the diagnosis that’s manageable” Wilson says. “But, once we have the diagnosis, we need the treatment, and the problem is that the treatment is at an impossible price.”