Replies to post #137185 on Biotech Values

[jbog]

That is going to hurt....

Gilead is down 20% pre market

[Preciouslife1]

Gilead Suffers First Hep C Drug Setback
By Adam Feuerstein

http://www.thestreet.com/_yahoo/story/11423015/1/gilead-suffers-first-hep-c-drug-setback.html?cm_ven=YAHOO&cm_cat=FREE&cm_ite=NA

FOSTER CITY, Calif. (TheStreet) Gilead Sciences(GILD) just had its first stumble in the race to develop an all-oral therapy for hepatitis C.
A two-drug regimen of Gilead's experimental GS-7977 plus ribavirin failed to suppress the hepatitis C virus in a group of difficult-to-treat patients who had also failed prior therapy, Gilead announced Friday.
Gilead's GS-7977 streak as the ultimate, flawless hepatitis C drug has now ended. Friday's negative results are a setback and not a fatal blow to the drug's future. However, Gilead spent $11 billion to gain control of GS-7977 through the acquisition of Pharmasset so any failure, no matter how small, is sure to be magnified in the eyes of investors.
Gilead shares plunged 19% to $44.50 in Friday pre-market trading.
In this study, ten hepatitis C genotype 1 patients with a prior "null" response to interferon and ribavirin were treated with a combination of GS-7977 plus ribavirin for 12 weeks. Within four weeks of completing treatment, six of eight patients relapsed, meaning the hepatitis C virus, which had been suppressed, came roaring back. Two patients have not relapsed, however they have only reached the two week post-treatment time point, Gilead said.

Null responders are among the most difficult to treat hepatitis C patients because prior therapy has not worked for them.
"These data answer an important question about the use of GS-7977 and ribavirin for the treatment of genotype 1 null responder patients, suggesting that additional direct acting antivirals may be necessary to effectively treat this patient population," said Norbert Bischofberger, Gilead's research chief, in a statement.

Further data on GS-7977 is coming soon, including important results from a study testing the drug in combination with ribavirin in genoptype 1 patients who have not been previously treated.
A chink in the previous untarnished armor of GS-7977 may mean a boost for other companies developing new oral hepatitis C drugs, including Vertex Pharmaceuticals(VRTX_), Bristol-Myers Squibb(BMY_) and Idenix Pharmaceuticals(IDIX) .. Written by Adam Feuerstein in Boston.

[DewDiligence]

From GILD’s CC today: GILD has not yet seen BMY’s data on the BMS-750052 + GS-7977 combo that will be presented at EASL. (GILD will see the abstract before the conference, however.)

[mcbio]

Gilead Announces Data for Genotype 1 Null Responder Hepatitis C Patients Enrolled in ELECTRON Study

Does anyone know the estimated size of the genotype 1 null responder HCV patient population? And, for that matter, the size of the null responder HCV patient population across all other genotypes.

[iwfal]

HCV -

Gilead Sciences, Inc. (NASDAQ:GILD) announced today that the majority of hepatitis C genotype 1 patients with a prior “null” response to an interferon (IFN)-containing regimen enrolled in the ongoing ELECTRON study experienced viral relapse within four weeks of completing 12 weeks of treatment with GS-7977 plus ribavirin (RBV)

.

I am somewhat surprised that the market and this board consider the above results a surprise. To date no two DAA (no ifn) has shown good efficacy in G1a patients (G1b is, apparently, a different matter - see #msg-67597202). So why would one DAA + rib (a relatively weak drug) be expected to be a cure? I'd agree it was a trial worth running on the off chance of a surprise - but the market reaction was as if it was expected to work.

Note also that to date all the SVR data in dual DAA (no PR) has been in null responders. I think there is a general tendency to believe that even a 30 or 40% SVR in nulls will map to >95% response in naives. Certainly this seems possible - but hardly a sure thing since resistance to ifn/rib is probably a somewhat different thing than being resistant to 2 DAAs. I.e. Null responders are a pool of HCV patients enriched with strains resistant to ifn/rib. It is NOT a pool of HCV patients enriched with strains resistant to 2 DAAs. Thus if, in the extreme case, resistance to ifn/rib and resistance to 2DAAs are entirely independent states you would expect to see the SVR rate of 2DAAs in inf/rib nulls be exactly the same as the SVR rate of 2DAAs in treatment naive patients.

(Obviously I do NOT expect resistance to ifn/rib and resistance to 2DAAs to be entirely independent - but I would expect some independence - how much is the question. We should run a quiz - in the G1a population what SVR rate should be expected of the best 2DAA option of the first 3 2DAA trials we see. I'd guess less than 85% - and think there is some small chance it is as low as 50%.)