Survival Data Still Key for Medarex
Medarex
(MEDX)
finished Friday's session up nearly 5% after the public release of the biotech company's research abstracts on its melanoma candidate ipilimumab. But analysts said there were few surprises in the data -- good or bad.
"Our conclusion is that we see little new information in the abstracts to be very excited about; however, we find Abstract No: 20004: 'Prolonged survival in objective responders to ipilimumab therapy,' to continue to suggest that durable responses that translate into an overall survival benefit remains the key to 010's approvability," wrote Susquehanna analyst Jason Kolbert, who has a neutral rating on the stock.
Overall survival data has been the topic of discussion for this drug as the company, which recently -- after discussion with the Food and Drug Administration -- changed the primary endpoint of a late-stage trial to overall survival from measurements of tumor progression. It also delayed filing for approval.
How a Study's Endpoints Changed
To review: Last December, Medarex said that a key ipilimumab phase II study failed to meet its primary endpoint, "which was to rule out a best objective response rate of less than 10 percent."
That trial and two concurrent late-stage studies, on ipiluminab as a second-line treatment, involved melanoma patients previously treated with chemotherapy. Discussing the results, the company pointed investors toward the "totality of the data" as what the FDA will use to review ipilimumab with plans to still file for approval by mid-2008.
The abstracts released Thursday, ahead of the American Society of Clinical Oncologists' annual meeting, contained more data.
"The best objective response rates (BORR) from the three second-line trials (top-line data reported December '07) were essentially in-line with previous disclosures and ranged from 5.8% (study -008, 10mg/kg) to 15.8% (study -007, 10mg/kg + budesonide)," wrote UBS analyst Jeff Elliott. "Although the BORR from study -008 was closer to the low end of previously observed responses, we maintain our view that response rate is not the most important efficacy measure for ipilimumab and that survival data will be key."
Here's why: On April, 25, Medarex and
Bristol-Myers Squibb
(BMY) - Get Report
announced that after meeting with the FDA, they would delay their submission for ipilumumab (previously expected in mid-2008) because the FDA had requested additional overall survival data to demonstrate the benefit of the drug.
The company disclosed with the filing delay that it's in discussions with U.S. regulators to change the endpoint of this trial from progression free survival to overall survival.
Medarex and partner Bristol-Myers are running a phase III trial in previously untreated patients, looking at ipilimumab plus dacarbazine vs. darcarbazine by itself. Results are expected in 2009. An eventual FDA filing will include survival data from this randomized phase III first-line trial and also phase II second-line studies mentioned above that will be presented at the ASCO meeting later this month.
"Included in the abstracts were a number of analyses of overall survival, which suggested a potential benefit when compared to historical data. The utility of these analyses is limited however, reaffirming the importance of the ongoing first-line, placebo-controlled trial," Wrote UBS' Elliott, who has a buy rating and a $12 price target for the stock.
The Pfizer Effect
One shadow casting doubt on investors' minds: On April 2,
Pfizer
(PFE) - Get Report
halted a phase III study of melanoma drug tremelimumab after an interim review concluded that the drug would not prolong survival any more than currently prescribed chemotherapy.
Medarex shares fell about 8% the first trading day after that news. The problem is that Pfizer's tremelimumab and Medarex and Bristol's ipilimumab are designed to work in similar ways by blocking a cell receptor called CTLA-4 and essentially activating the body's immune system to seek out and destroy cancer cells
The abstract for the phase III tremelimumab trial isn't available until May 31, so comparison with ipilimumab isn't yet possible, noted Elliott in his note to investors Friday.
Looking ahead, some Wall Street analysts are optimistic about ipilimumab's potential. Earlier this week, Needham & Co. analyst Mark Monane upgraded the stock to buy from hold, citing among other things the upcoming presentations on ipilimumab as a possible catalyst for the stock.
Medarex also released abstracts for additional programs in prostate cancer among others, but analysts viewed these as immaterial.
Investor frustration over the past six months is evident in the stock, which has given up more than 35% since the company announced in December the phase II ilimumab study didn't meet its primary endpoint. But no news seemed to be good news for shares Friday, as the stock ended the session up 4.7% at $8.13.
ASCO Thursday night released thousands of research abstracts on its Web site,
. For a useful guide on searching through the abstracts, check out
Adam Feuerstein's ASCO Abstract Preview
.
And for abstract reviews on
Genentech
(DNA)
and
Eli Lilly
(LLY) - Get Report
, check out these related articles:
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- Eli Lilly's Alimta Shows Promise in Cancer Study