Is Onyx Pharmaceuticals’ new, next generation proteasome inhibitor a new miracle drug—or just another “bit player” on the multiple myeloma scene? It depends who you ask.
The company is pushing comparisons with the only currently available FDA proteasome inhibitor, Velcade. Company officials point to ongoing research study results which show less risk of developing peripheral neuropathy (PN) in patients who take carfilzomib vs those who are on Velcade.
There is also some evidence carfilzomib may work in as many as 20% of patients who have become Velcade resistant.
Every expert I spoke with here at ASCO agreed the potential of combining carfilzomib with other novel therapies like Thalomid and Revlimid is exciting. Studies are already showing impressive results using these combo’s.
But what are the negatives? After all, no drug is perfect. Let me share some anecdotal evidence with you.
1) Yes, Phase 2 and 3 studies show impressive response numbers. But so do other new developmental anti-myeloma drugs like especially, pomalidomide. Both of these drugs seem destined for FDA approval within the next two years. In fact, Celgene’s pomalidomide’s overall numbers may even be a bit better, especially in patients who are relapsed and refractory.
2) A high level, unnamed industry source pointed out that carfilzomib research which shows little associated PN—the company’s biggest selling point for approval of carfilzomib—only uses unreasonably low doses in their studies which may not be strong enough to be effective in relapsed patients. The implication is this is intentional. Low dosing logically produces far less PN. For example, when Velcade is dosed once weekly instead of once every four days, PN cases drop to equally low levels.
3) A fellow journalist who specializes in covering myeloma related news, stressed carfilzomib’s anti-myeloma data as a single agent are underwhelming and much lower than those from ongoing pomalidomide studies.
4) Carfilzomib isn’t a cure. Like other multiple myeloma novel therapy agents, carfilzomib will only help control myeloma in 70-80% of patients.
To be fair, none of the available novel therapy agents cure multiple myeloma—and although it is unclear how long carfilzomib will work, there is no reason to believe it won’t be effective at least as long as Velcade or Revlimid.
Barring an unexpected last minute glitch in the data, it seems clear carfilzomib will soon join Thalomid, Revlimid, Velcade and, most likely pomalidomide, as the cornerstones of future multiple myeloma therapy.
I was fortunate enough to sit down with Dr. Michael Kauffman, Onyx Pharmaceuticals’ Research Director, for a one-on-one interview Friday. I will run that interview here tomorrow.
Feel good and keep smiling! Pat