Elanco Animal Health Announces U.S. Food and Drug Administration (FDA) Approval of Imrestor™ (pegbovigrastim injection)

Greenfield, Ind. (March 17, 2016) — Today, Elanco Animal Health, a division of Eli Lilly and Company (NYSE: LLY), announced the approval of ImrestorTM (pegbovigrastim injection) – the first product of its kind for the dairy industry.

Available only by veterinary prescription, Imrestor is now FDA approved for the reduction in the incidence of clinical mastitis in the first 30 days of lactation in periparturient dairy cows and periparturient replacement dairy heifers. Imrestor is a protein that helps support the natural function of a dairy cow’s immune system during the critical time around calving, when she is most vulnerable to mastitis.

“Imrestor is an innovative new approach for reducing clinical mastitis by proactively helping to restore the function of a cow’s immune system,” explained Paul Rapnicki, DVM, MBA, Associate Technical Advisor, Elanco Animal Health.

Pivotal efficacy studies conducted for FDA approval showed a 28 percent reduction in clinical mastitis incidence among cows and heifers that received Imrestor compared with control animals.1 Mastitis is the most common disease among dairy cows, affecting as many as 1 in 4 cows.2 Clinical mastitis affects each cow’s potential leading to reduced conception rates3, an increased risk for another case of mastitis4, and lost milk production potential throughout the lactation5.

Dairy Cows Experience Immune Suppression At Calving

Immune suppression at calving can leave cows vulnerable to infection and an increased risk of mastitis.6 Dairy cows and heifers are in need of protection particularly at calving due to a decline in neutrophils – the primary type of white blood cell that recognizes and destroys harmful bacteria. Imrestor helps restore the function7* and increase the number1,7* of neutrophils at calving which helps the cow to fight invading bacteria that cause mastitis.

“We know that even the best producers need a little help protecting their dairy herds. Imrestor is a proactive approach that can help keep cows healthy and help reduce the frustration, financial strain and stress associated with treating mastitis,” added Rapnicki.

Elanco shared news of the Imrestor approval today during a U.S. Department of Agriculture (USDA) meeting where antibiotic alternatives for use in food animals were discussed. Mastitis is the most common illness treated with antimicrobials in dairy cows8.

The launch of Imrestor is aligned with Elanco’s eight-point antibiotic stewardship plan that ensures the responsible use of antibiotics, reduces shared-class antibiotic use and replaces antibiotics with alternatives. The plan was outlined by Elanco President Jeff Simmons at a White House antibiotic stewardship forum last year.

Available in pre-filled, single-dose syringes, Imrestor is administered with two injections – one seven days prior to the anticipated date of calving** and the other within 24 hours after calving – thus helping to protect the cow against mastitis when she needs it most.

Imrestor does not require a meat or milk withdrawal period. Imrestor will be available for purchase in 10, 50, and 100 dose pack sizes. The product availability date will be announced at a later time. Dairy producers are encouraged to contact their veterinarian to discuss incorporating Imrestor into their herd health program.


Not for use in humans. Keep out of reach of children. In case of accidental self-injection, wash the site of injection thoroughly with clean running water. Foreign proteins such as pegbovigrastim have the potential to cause anaphylactic-type reactions. No withdrawal period or milk discard time is required when used according to the labeling. Do not use Imrestor to treat cows with clinical mastitis because effectiveness has not been demonstrated for this use. Some cases of hypersensitivity-type reactions have been observed in studies outside the United States within five minutes to two hours, occurring most often after the first administration of Imrestor. These reactions resolve within hours of onset with or without therapeutic intervention and have not been shown to reoccur with subsequent injections of Imrestor. For complete safety information, see product label attached.


*The clinical significance of this data has not been demonstrated
**4-10 days to accommodate management schedules


Elanco provides comprehensive products and knowledge services to improve animal health and food- animal production in more than 70 countries around the world. We value innovation, both in scientific research and daily operations, and strive to cultivate a collaborative work environment for more than 6,500 employees worldwide. Together with our customers, we are committed to raising awareness about global food security, and celebrating and supporting the human-animal bond. Founded in 1954, Elanco is a division of Eli Lilly and Company. Our worldwide headquarters and research facilities are located in Greenfield, Indiana. Visit us at


1Elanco Animal Health, Data on File.
2 Holland, J., et al. Assessing the farm-level cost of mastitis. J. Dairy Sci. 2015;98 (Suppl. 2):234. (Abstr 137)
3 Santos JEP. Effect of timing of first clinical mastitis occurrence on lactational and reproductive performance of Holstein dairy cows. Anim Reprod. 2004;80:31-45.
4 Pantoja JC, Hulland C, Ruegg PL. Somatic cell count status across the dry period as a risk factor for the development of clinical mastitis in the subsequent lactation. J Dairy Sci. 2009;92:139-148.
5 Wilson DJ, González RN, Hertl J, et al. Effect of clinical mastitis on the lactation curve: A mixed model estimation using daily milk weights. J Dairy Sci. 2004;87:2073-2084.
6 Aitken SL, Corl CM, Sordillo LM. Immunopathology of mastitis: insights into disease recognition and resolution. J Mammary Gland Biol Neoplasia. 2011;16:291-304.
7 Kimura K. et al. Effect of recombinant bovine granulocyte colony-stimulating factor covalently bound to polyethylene glycol injection on neutrophil number and function in periparturient dairy cows. J Dairy Sci. 2014;97:1-10.
8 Mitchell JM, Griffiths MW, McEwen SA, McNab WB, Yee AJ. Antimicrobial drug residues in milk and meat: causes, concerns, prevalence, regulations, tests, and test performance. J Food Prot. 1998 Jun; 61(6):742-56. 

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