Late-stage success for Sanofi/Regeneron RA drug sarilumab

SARILUMAB

PRONUNCIATION sar il’ ue mab

THERAPEUTIC CLAIM Treatment of rheumatoid arthritis and
ankylosing spondylitis

CHEMICAL NAMES

1. Immunoglobulin G1, anti-(human interleukin 6 receptor α) (human REGN88 heavy
chain), disulfide with human REGN88 light chain, dimer

2. Immunoglobulin G1, anti-(human interleukin-6 receptor subunit alpha (IL-6RA,
membrane glycoprotein 80, CD126)); human monoclonal RGN88 γ1 heavy chain (219-
214′)-disulfide with human monoclonal RGN88 κ light chain dimer (225-225”:228-
228”)-bisdisulfide

MOLECULAR FORMULA C6388H9918N1718O1998S44

MOLECULAR WEIGHT 144.13 kDa

SPONSOR Regeneron Pharmaceuticals, Inc.

CODE DESIGNATION REGN88, SAR153191

CAS REGISTRY NUMBER 1189541-98-7

sarilumab

Sarilumab (REGN88/SAR153191) is a fully-human monoclonal antibody directed against the IL-6 receptor (IL-6R).  Sarilumab is a subcutaneously delivered inhibitor of IL-6 signaling, which binds with high affinity to the IL-6 receptor.  It blocks the binding of IL-6 to its receptor and interrupts the resultant cytokine-mediated inflammatory signaling.

Sanofi and Regeneron’s investigational rheumatoid arthritis drug sarilumab has succeeded in a late-stage trial.

The year-long Phase III study enrolled 1,200 patients with active, moderate-to-severe RA who were inadequate responders to methotrexate. Patients were randomised to one of three subcutaneous treatment groups, all in combination with MTX and dosed every other week – sarilumab 200mg, 150mg or placebo.http://www.pharmatimes.com/Article/13-11-22/Late-stage_success_for_Sanofi_Regeneron_RA_drug.aspx

Sarilumab is a human monoclonal antibody against the interleukin-6 receptor.

Regeneron and Sanofi are currently co-developing the drug for the treatment of rheumatoid arthritis, for which it is in phase III trials. Development inankylosing spondylitis has been suspended after the drug failed to show clinical benefit over methotrexate in a phase II trial.^[1][2]

On May 15th, 2013, both companies announced that 2 new trials were starting (COMPARE and ASCERTAIN) and the first patients had already been enrolled.^[3]

On November 22nd, 2013, both companies On May 15th, 2013, both companies announced positive phase 3 results for the RA-MOBILITY trial

1.  “Statement On A Nonproprietary Name Adopted By The USAN Council: Sarilumab”. American Medical Association.
2.  http://investor.regeneron.com/releasedetail.cfm?releaseid=590869
3.  http://en.sanofi.com/Images/33027_20130515_sari_en.pdf

fully human monoclonal antibody directed against the interleukin-6 receptor (IL-6R) in combination with methotrexate (MTX) therapy improved disease signs and symptoms as well as physical functionw while inhibiting progression of joint damage in adults with RA who saw little improvement through MTX therapy alone.

Sarilumab met all three primary endpoints of the 52-week SARIL-RA-MOBILITY Phase III trial by demonstrating clinically relevant and statistically significant improvements compared to the placebo group in the two groups treated with the drug candidate. The trial enrolled about 1,200 patients with active, moderate-to-severe rheumatoid arthritis who were inadequate responders to MTX therapy.

Of patients treated with the 200 mg dose of sarilumab plus MTX, 66% saw improvement in signs and symptoms of RA at 24 weeks, as measured by the American College of Rheumatology score of at-least 20% improvement. The percentage dipped to 58% of sarilumab 150 mg dose patients, and 33% of placebo patients.

Sarilumab 200 mg patients showed the least progression of structural damage after 52 weeks, registering a 0.25 change in the modified Van der Heijde total Sharp score. That contrasts with scores of 0.90 in patients taking sarilumab 150 mg, and 2.78 in the placebo group.

In addition, sarilumab 200 mg patients showed improvement in physical function, as measured by change from baseline in the Health Assessment Question-Disability at week 16. However, the companies did not quantify those results in their announcement. Sanofi and Regeneron said additional analyses of efficacy and safety data from SARIL-RA-MOBILITY will be presented “at a future medical conference.”

“We are encouraged by these Phase III results and the impact sarilumab demonstrated on inhibition of progression of structural damage assessed radiographically in this study,” Tanya M. Momtahen, Sanofi’s sarilumab global project head, said in a statement.

Sarilumab—known as SAR153191 and REGN88—blocks the binding of IL-6 to its receptor and interrupts the resultant cytokine-mediated inflammatory signaling characteristic of RA. Sarilumab was developed using Regeneron’s VelocImmune® antibody technology.

The positive results continue what has been mostly strong success in clinical trials for the partners, whose development collaborations include alirocumab (REGN727), dupilumab (REGN668), and enoticumab (REGN421). Alirocumab is a PCSK9 antibody being evaluated for its ability to manage LDL cholesterol, including in people who do not get to their target LDL levels using statin medicines alone. Dupilumab is an antibody to the receptors for interleukin-4 and interleukin-13 under evaluation in atopic dermatitis and eosinophilic asthma. Enoticumab is a fully human monoclonal antibody to delta-like ligand-4 (Dll4) now in Phase I study for advanced malignancies.

On its own, however, Sanofi’s R&D efforts have shown more mixed results, with the pharma giant earlier this month ending development of cancer drug candidate fedratinib (SAR302503) after it was placed on clinical hold by the FDA following reports that some patients in clinical trials developed symptoms consistent with Wernicke’s encephalopathy. Another cancer compound, iniparib, had its development halted earlier this year after a disappointing Phase III trial.