Vertex: Complete Response Letter (CRL) From U.S. FDA

On February 5th it was press released that Vertex Pharmaceuticals received a CRL from the FDA.  A Food and Drug Administration CRL is issued when the FDA communicates to a company that an application to market a drug (NDA, new drug application) will not be approved in it's present form, and that the review by the FDA has been complete.
  
Vertex submitted a supplemental new drug application (sNDA) for the already approved Kalydeco.  The sNDA was filed for Cystic Fibrosis people 2 years and older, who have one of 23 residual function mutations in the cystic fibrosis gene.   Eight of the 23 were represented in a phase 2A study. It is estimated that over 1,500 people in the U.S. have one of the 23 gene mutations. The numbers do not seem all that large.  But if you factor in that Kalydeco is priced around $300k for annual therapy, then the numbers become quite large, up to around $450mn in potential annual revenue for the company if the sNDA was approved.
The 23 residual function mutations included in the sNDA were: 2789+5G- > A, 3849+10kbC- > T, 3272-26A- > G, 711+3A- > G, E56K, P67L, R74W, D110E, D110H, R117C, L206W, R347H, R352Q, A455E, D579G, E831X, S945L, S977F, F1052V, R1070W, F1074L, D1152H, and D1270N.  The press release is here Vertex Complete Response Letter.  More than likely the CRL was issued to Vertex because only eight of the 23 residual function mutations were represented in the phase 2A study.  Thank you for reading.

Orkambi Gets FDA Approval

Today the FDA approved the combination of Vertex's Lumacaftor and Kalydeco (Orkambi) for cystic fibrosis people, 12 years and older, with two copies (homozygous) of the F508del mutation. We originally wrote about Orkambi here Vertex Pharmaceutical Passes Advisory Committee, when they were front and center with the FDA advisory committee.

Orkambi has been appoved for CF patients despite the relatively small improvement in FEV1 in two F508del clinical studies.  How high is the bar set for other companies to get clinically significant improvement over Kalydeco as mono therapy for the G551D mutation, and Orkambi combination therapy, for patients 12 years and older, with two copies of the F508del mutation?

G551D Through 24 weeks Kalydeco 150 mg q12h

• 10.6% and 12.5% FEV1 improvement vs. placebo

G551D Through 48 weeks Kalydeco 150 mg q12h

• 10.5% and 10.0% FEV1 improvement vs. placebo
• 3,000 Worldwide Patients

F508del Through 24 weeks 2 tablets (ivacaftor 125 mg / lumacaftor 200 mg) q12h

• 2.6% and 3.0% FEV1 improvement vs. placebo
• 26,000 U.S. + EU Orkambi Patient Potential

These are the FEV1 (forced expired volume) numbers that other companies will be considering as significant, to improve current therapy for CF patients.  The side effect profile was mild, as a high percentage of patients completed the Vertex clinical trials.  The annual wholesale acquisition cost (WAC) will be priced at around $259,000 per patient for the Orkambi combination.  Thank you for reading.
 

Vertex Pharmaceuticals Passes Advisory Committee

Vertex's (VRTX) drug combo named Orkambi faced the advisory committee on Tuesday this week. The FDA document is here Orkambi Advisory Committee .  The advisory committee voted 12-1 to approve the combination for patients with Cystic Fibrosis who have two copies (homozygous) of the F508del mutation, 12 years and older.  So that opens their market to a substantially much larger population of 20,000 patients. The results from the two phase 3 studies 890-103 and 890-104 are as follows.

Study 809-103

Lumacaftor 400 mg + Ivacaftor 250 mg q12 at week 24 = 2.6% mean absolute improvement over placebo on FEV1 test.

 

Study 809-104

Lumacaftor 400 mg + Ivacaftor 250 mg q12 at week 24 = 3.0% mean absolute improvement over placebo on FEV1 test.

Orkambi 

Lumacaftor 200 mg + Ivacaftor 125 mg, proposed dose every 12 hours.

Lumacaftor and Ivacaftor was administered twice daily, with the safety profile seen as well tolerated. What's intriguing is the fact that Orkambi the proposed combo up for FDA approval is administered as Lumacaftor 200 mg, and Ivacaftor as 125 mg twice daily. In prior trials, Lumacaftor dosages at the 600 mg level, achieved better efficacy than the 400 mg Lumacaftor dose on FEV1.  The reason for using 400 mg instead of 600 mg, is because the drug-drug interaction of Lumacaftor tends to lessen the effects of Ivacaftor up to 80% as dosages increase. The final date for FDA approval falls on July 5th, of 2015, and in the fourth quarter for EU approval. With an annual therapy per patient price of around $300,000, the potential to achieve revenue up to six billion is attainable. Thank you for reading.                                                                                                                       

Patent Infrigement: Obvious or Nonobvious

As companies file for new chemical entity patents, the question of infringement on an existing drug becomes either obvious or nonobvious.  This link to an article titled Deuterated Drugs: Unexpectedly Nonobvious? is a nice paper by Ms. Kristen Buteau on what constitutes obvious from nonobvious inventions, and how it relates to drug companies such as Auspex, and Concert Pharmaceuticals.  The company that is applying for a new patent must present an unexpected difference between the claimed structures and the prior art. That difference may be the new drugs unexpected metabolism rate, other pharmacokinetic advantages, or a reduced dosing regimen compared to the prior drug.  But any unexpected difference must not be obvious, must be a skill or art in itself, such as the placing of deuterium on a drug that could have many options to choose from, potentially thousands, as the drug Cymbalta has.

Concert Pharmaceuticals is currently in a phase 1 trial to test d-Ivacaftor, which is the deuterated version of Ivacaftor, a drug that is currently approved for the treatment of Cystic Fibrosis.  Not only was the deuterated drug (d-Ivacaftor) patent filed before any mention of deuterium from Vertex Pharmaceutical, but the unexpected differences in pre-clinical studies suggest, that the deutered Ivacaftor version from Concert, improved pharmacokinetics to a high degree, both in-vitro and in-vivo, and may have the convenience of single 24 hour dosing compared to twice daily.  This phase 1 trial will show how (deuterated) d-Ivacaftor does in it's first in human clinical trial on safety, tolerability, and PK, versus the placebo Ivacaftor, and demonstrate whether some of the pre-clinical results are equally impressive in healthy human subjects. Thank you for reading.

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