Originally published Feb. 26.
By Turna Ray
Pfizer has enlisted Medco's help to educate physicians about HIV treatments that are administered with the help of companion genomic tests, Pharmacogenomics Reporter has learned.
While the so-called "HIV adherence program," is for all genomically targeted HIV drugs, educational efforts by Medco will include information on Pfizer's CCR5-antagonist Selzentry, which requires a companion diagnostic to determine the tropism status of the virus prior to treatment. The collaboration between Medco and Pfizer began in November.
"The program, as it exists today, provides guideline-based information to physicians about all current genomic tests for HIV, regardless of whether the testing focuses on the virus’ genome or the patient’s," a Medco spokesperson told Pharmacogenomics Reporter this week. "This includes, but does not exclusively focus on, tropism testing."
Ahead of administering Selzentry, physicians are required by the drug's label to establish the tropism status of a patient's HIV by "a highly sensitive tropism assay." Since 2006, Pfizer has had a non-exclusive agreement with Monogram Biosciences, a subsidiary of the Laboratory Corporation of America, to market and distribute globally its tropism test Trofile [see PGx Reporter 12-06-2006].
However, Pfizer's interest in working with Medco to educate doctors about HIV genomic testing may have something to do with the unimpressive sales of Selzentry.
According to Bryan Dechairo, Senior Director of Personalized Medicine at Medco, Pfizer partnered with the pharmacy-benefits manager after the drug developer did not see the market it had envisioned for Selzentry. Speaking at a personalized medicine conference in Philadelphia this week, Dechairo said that the drug giant turned to Medco to help educate physicians about genomic testing associated with Selzentry.
At the same conference, Bill Welch, former chief commercial officer at Monogram, also acknowledged that there was an internal belief at Pfizer that sales of the drug were not as large as they should be.
After the FDA granted accelerated approval for Selzentry in August 2007, industry analysts were projecting drug sales of more than $500 million by 2011. However, Selzentry had about $49 million in sales for 2008, according to Credit Suisse.
Genetic testing to establish tropism status, the very feature that was supposed to differentiate the drug from competitors on the market, deterred doctors from venturing to prescribe it for their patients. The fact that there are competitors to Selzentry that don't require genetic testing —such as Merck's integrase inhibitor Isentress and Bristol-Myers Squibb/Gilead's combination therapy Atripla — didn't help either.
Another setback to Selzentry's adoption, according to some analysts, is the drug's price tag, which ranged between $13,000 and $26,000 per year based on dosage, in addition to around $2,000 for Monogram's tropism test. This is a significant premium to competing HIV drugs on the market, which cost around $11,000 per year or less.
On top of the high cost of Selzentry and companion testing, a focus group of five HIV specialists organized by Panel Intelligence in March 2008 revealed that doctors were concerned about the uncertain reimbursement environment, in which tropism testing may or may not be covered by insurers based on their prior authorization requirements.
Late last year, Pfizer shifted commercial activities related to Selzentry over to ViiV Healthcare, a new spin-off venture between Pfizer and GlaxoSmithKline to market the two firms' HIV treatments. The fact that Selzentry was not a major money-maker for Pfizer probably made it easier to hand it off to ViiV, in which Pfizer holds a 15 percent controlling share. At the same time, Pfizer's educational effort with Medco shows that the company hasn't given up on the drug and is still attempting to drive its adoption.
The focus group by Panel Intelligence did conclude that "a possible new market opportunity exists [for Selzentry] if clinical trials can demonstrate improved efficacy and outcomes in treatment-naïve patients."
In November last year, the same month Pfizer and Medco launched their HIV adherence program, the FDA expanded the use of Selzentry in combination with other antiretroviral agents in treatment-naive adults with CCR5-tropic HIV-1 virus.