Antiplatelets: One's Powerful, One's Reversible
Data from the Phase III clinical trial of prasugrel, released at the American Heart Association (AHA) meetings in November, suggest that Lilly's new antiplatelet therapy is much
more effective at reducing harmful blood clots for patients with acute coronary syndrome (ACS) than clopidogrel (Plavix),
one of BMS's biggest drugs. But the new drug's increased efficacy comes at a price: It causes more bleeding than clopidogrel,
and it probably cannot be used as widely.
"Coming out of the AHA meeting, our feeling is that prasugrel is clearly an approvable drug because of the dramatic efficacy,"
said Barbara Ryan, pharmaceutical analyst at Deutsche Bank. "The question is: What patient are you going to use this drug
in? Our view would be that doctors are going to move cautiously. The ACS population is a market of about $1.5 billion. If
you eliminate the elderly and people with compromised renal systems or who have already had a stroke, you get a market of
$750 million. And Lilly won't get all of that, so you really have a drug worth hundreds of millions."
Competition for prasugrel lurks just up the pipeline. Ticagrelor has one big potential advantage over prasugrel: A physician can turn off its effects. "Ticagrelor is a reversible agent that
you can stop very quickly," says Jeremy Goldman, MD, an analyst at Decision Resources. "If you can't stop the drug, it's difficult
to go for coronary bypass surgery because your patient may bleed, and that could be fatal."
Ticagrelor is going head-to-head against clopidogrel in worldwide Phase III trials enrolling 18,000 patients, according to
the Wolters Kluwer R&D Insight database. A Lehman Brother's analysis projects worldwide ticagrelor sales of $1.5 billion by
Osteoporosis: Keep Your Eye on Anabolics
Merck’s osteoporosis blockbuster Fosamax (alendronate) loses patent protection in February. FDA has granted tentative approvals
to IVAX, Barr, and Teva to market generic versions of the mainstay bisphosphonate therapy then. And at about the same time
a major new drug will launch. "That's enough to make the osteoporosis market a pretty interesting one to watch next year,"
says Murray Aitken, analyst at IMS Health.
A lot of the interest will be seeing what happens to the new launch, bazedoxefine, Wyeth and Ligand's jointly developed drug for postmenopausal osteoporosis, which launches at about the same time. Bazedoxifene
is a selective estrogen receptor modulator (SERM), like Lilly's Evista (raloxifene). That could create problems for the new
drug. "Raloxifene has not been proven to reduce the risk of hip fractures the way bisphosphonates have," said Hosam Kamel,
MD, professor of medicine at the University of Arkansas Medical School, in Little Rock.
Other new approaches to osteoporosis wait in the wings. Several, like bisphosphonates, aim to decrease the level of bone breakdown,
or resorption. Amgen's denosumab, for example, a monoclonal antibody aimed primarily at bone cancer and multiple myeloma, is in Phase III clinical trials for
osteoporosis too. The drug inhibits the differentiation of osteoclasts, which resorb bone. Odanacatib inhibits cathepsin K, an enzyme produced by osteoclasts.
"Bone formation, not reduced resorption, is the holy grail," said Kevin Richard, an analyst at Leerink Swann. "You have to
keep your eye on the anabolic therapies now, as opposed to the antiresorptives, like the bisphosphonates."
Ronacaleret is one of several new therapies aimed at increasing levels of parathyroid hormone, which promotes anabolic bone formation.
The small molecule by NPS Pharmaceuticals/GlaxoSmithKline creates transient increases of PTH by blocking calcium-sensing receptors
on the surface of parathyroid cells.