Status: marketed; some formulations phased out

Organizations involved:

Lilly, Eli & Co. – R&D; World mark.; Parent

Hoffmann-La Roche Ltd. – World mark.

Lilly France S.A. – Manuf.

Lupin Labs. – India mark.

Genentech, Inc. – Tech.; Patent dispute

University of California – Patent dispute

City of Hope National Medical Center – R&D; Tech.; Patent dispute

Cross ref.: See the Insulin Products entry (#630).

Description: Insulin Human Injection (rDNA origin) or Humulin refers to aqueous formulations of recombinant human insulin expressed by a transformed Escherichia coli (E. coli) cell line. Until 1986, Lilly manufactured recombinant insulin using the “two-chain” or crb method developed originally by Genentech, Inc. This involved expressing the insulin A and B protein chains separately and then chemically forming the disulfide bonds between the chains to form the dimeric insulin molecule. In 1986, Lilly switched to a process (prb method) involving expression of a single-chain proinsulin fusion protein in E. coli, with subsequent proteolytic cleavage to form insulin.

Humulin (referring to the insulin component and/or this family of products) is available in a variety of formulations. As discussed in the Status section, several are being phased out. [See the Insulin Products entry for further information about insulin formulations]:

a) Humulin R (regular) consists of zinc insulin crystals dissolved in a clear fluid. Humulin R has nothing modified or added to alter the speed or length of insulin action. It takes effect rapidly (but not as rapid as insulin aspart and insulin lispro) and has a relatively short duration of activity (4 to 12 hours).

b) Humulin N (NPH; isophane) is a crystalline suspension of insulin with protamine and zinc providing an intermediate-acting insulin with a slower onset of action and a longer duration of activity (up to 24 hours) than that of regular insulin.

c) Humulin L (Lente) is an amorphous and crystalline zinc suspension of intermediate-acting insulin with a slower onset and a longer duration of activity (up to 24 hours) than regular insulin.

d) Humulin U (UltraLente) is a crystalline suspension of insulin with zinc providing a slower onset and a longer and less intense duration of activity (up to 28 hours) than regular insulin or the intermediate-acting insulins (NPH and Lente).

e) Humulin 50/50 is a mixture of 50% Human Insulin Isophane Suspension and 50% Human Insulin Injection. It is an intermediate-acting insulin formulation with a more rapid onset of action than regular insulin. The duration of activity may last up to 24 hours following injection.

f) Humulin 70/30 is a mixture of 70% Human Insulin Isophane Suspension and 30% Humulin R (regular). It is an intermediate-acting insulin combined with the more rapid onset of action of regular insulin. The Isophane (N; NPH) begins to act before the R finishes and continues to work longer than the R. The duration of activity may last up to 24 hours.

Most Humulin formulations are packaged in 10 mL vials containing 100 units/mL (U-100) or 1,000 units/vial (U-1000). Humulin Pens (autoinjectors) are prefilled with 300 units of either Humulin 70/30 or Humulin N in boxes of five pens. Many of these formulations with recombinant insulin replaced earlier comparable formulations containing semi-synthetic human insulin (porcine insulin converted to human insulin).

Nomenclature: Insulin, rDNA/Lilly [BIO]; Humulin R [TR]; Regular Insulin Human Injection (rDNA origin) [FDA for Humulin R]; Human Insulin (rDNA origin) Isophane Suspension [FDA for Humulin N]; Human Insulin (rDNA origin) Zinc Suspension [FDA for Humulin L]; Human Insulin (rDNA origin) Extended Zinc Suspension [FDA for Humulin U]; 70% Human Insulin Isophane Suspension, 30% Human Insulin Injection (rDNA origin) [FDA fro Humulin 70/30]; 50% Human Insulin Isophane Suspension, 50% Human Insulin Injection (rDNA origin) [FDA for Humulin 50/50]; Insulin Biosynthetic Human [FDA]; 9004-10-8 [CAS RN]; Human Insulin (rDNA origin) isophane suspension [SY for Humulin N]; NPH [SY for Humulin N]; Ultralente [SY used by Lilly for Humulin U (Ultralente is reg. to Novo Nordisk)]; Lente [reg. to Novo Nordisk)]; zinc-insulin crystals [SY]; Huminsulin [TR in Germany, Switzerland]; Humuline [TR in the Netherlands]; Umuline [TR in France]; Humulina [TR in Spain, Austria, Belgium]

Companies.: Humulin was originally (starting in 1981) manufactured at Lilly facilities in Speke, U.K., with this being the manufacturing site for the world’s first commercial recombinant protein. Humulin has more recently been reported to be manufactured by Lilly France S.A. (Fegersheim, France); at facilities in Speke, U.K., near Liverpool, starting in 1981; and at Lilly’s automated, 114,000 sq. ft., “B132” facility in Indianapolis, IN. This facility has adopted semicontinuous batch manufacturing operations, allowing steps with different cycle times to run continuously or asynchronously. The two discontinued U.S. formulations of Humulin were manufactured at Indianapolis.

Humulin is jointly marketed worldwide by Eli Lilly and Hoffmann-La Roche Ltd., including Hoffmann-La Roche Inc. in the U.S. Humulin was originally marketed in Japan by Shionogi, but Lilly regained rights and markets it in Japan.

In June 2010, Wal-Mart and Lilly concluded an agreement for Wal-Mart to markt a co-branded version of Humulin in its U.S. pharmacies. This was Lilly’s first co-branded product with a retail pharmacy, and will replace Wal-Mart’s current Relion insulin brand.

In April 2011, Eli Lilly India and Lupin Labs. entered into a strategic collaboration to promote and distribute in India Lilly's Huminsulin products, including Huminsulin R, Huminsulin NPH, Huminsulin 50/50, Huminsulin 30/70 and Humapen Ergo II.

Manufacture: See the Insulin Products entry for further information about insulin manufacture. As originally manufactured by Lilly, using the methods/technology developed by Genentech (for manufacture of insulin crb), recombinant insulin was produced by large-scale independent fermentation of E. coli stain K12 transformed to express either the A or B chain. The A and B chains were independently purified and then chemically combined, forming disulfide bonds between the chains, resulting in insulin with chemical and biologic properties substantially identical to human insulin.

Starting in 1986, large-scale manufacture using insulin prb methods/technology developed by Lilly is performed by recombinant expression of a chimeric tryptophan synthetase–human proinsulin fusion protein in plasmid-transformed E. coli cells. The E. coli express fusion proteins consisting of tryptophan synthetase linked to proinsulin by a methionine residue (TypLE’ Met Proinsulin). This is subjected to cleavage (removal of trypLE’ Met) using cyanogen bromide (CNBr) and oxidative lysis to produce human proinsulin-(S-SO3-)6, with ‘S-S-SO3-’ bearing the S-sulfonate group. The human proinsulin-(S-SO3-)6 is refolded and disulfide bonds formed, e.g., by reduction with cysteine, to provide purified human proinsulin. This human proinsulin is converted to insulin and C-peptide using the enzymes carboxypeptidase-B and trypsin to remove the C-peptide. This prb method has advantages over the earlier crb method, e.g., it involves only one, rather than two, independent fermentation and purification schemes.

In Jan 2007, Lilly halted ongoing construction of a new plant in Prince William County, Virginia, slated for recombinant insulin manufacture.

FDA class: Drug NDA; now over-the-counter (OTC)

Approvals: Date = 19821028; first approval, NDA; for Humulin R manufactured by the “two-chain” method

Date = 19850930; NDA supplement; Indication = approval of Humulin L Injection

Date = 19860000; NDA supplement; Indication = approval of Humulin L formulation buffered for use in infusion pumps, and new prb recombinant manufacturing method

Date = 19870610; NDA supplement; Indication = approval of Humulin U

Date = 19890425; NDA supplement; Indication = approval of Humulin 70/30

Date = 19920429; NDA supplement; Indication = approval of Humulin 50/50

Date = 19940331; NDA supplement for Humulin R

Date = 19980806; NDA supplement; Indication = approval of Humulin 70/30 Pen

Date = 20100616; NDA supplement; Indication = labeling revision

Indications: [As over-the-counter (OTC) or non-prescription drugs, Humulin formulations do not have traditional, health care professional, product inserts/labeling, according to Lilly’s medical information department]

Status: Humulin was the first recombinant product to receive FDA approval in 1982. Humulin was evaluated and approved by the Center for Drug Evaluation and Research, FDA, as a drug (New Drug Application), not biologic, due to it being an analog of a previously approved drug (animal-derived insulin).

In July 2005, Lilly reported its was discontinuing Humulin L Lente and Humulin U Ultralente (along with its pork insulins), citing a drop in sales and use by diabetics. Supplies were expected to be exhausted around the end of 2005. Lilly reported, “Use of these longer-acting insulins has declined by more than 70% over the past five years due to newer insulin therapies that have increased the number of treatment options for patients. It is estimated that less than 2% of the patients with diabetes who use insulin in the U.S. will be impacted by this discontinuation...Healthcare providers should consider switching patients to NPH human insulin or a basal insulin analog.”

No centralized approval in EU. European approvals are country-by-country.

Tech. transfer: For Humulin R, Humulin R Pen, Humulin 70/30, Humulin 50/50, Humulin U, Humulin L, and Humulin N, FDA reports, “There are no unexpired patents for this product in the Orange Book Database,” i.e., that relevant U.S. patents have expired. DataMonitor and ABN Ambro report that U.S. patent protection for Humulin expired in 2002.

Some recombinant manufacturing technology was licensed from Genentech, which received royalties from sales of Humulin until Aug. 1998. In a licensing deal originally negotiated in August 1978 and renegotiated in July 1980, Genentech received 8% royalties from Lilly’s sales of recombinant insulin (as reported by www.recap.com). As discussed in the Recombinant DNA Product entry (at the beginning of this section), Genentech is appealing a $500+ million award to the City of Hope Medical Center (COH) arising from a 1976 contract and patent licensing dispute involving COH developing basic cloning technology for Genentech, including involvement in recombinant insulin development. Genentech is appealing to the California State Supreme Court.

In late 1997, the Court of Appeals for the Federal Circuit (CAFC; University of California vs. Eli Lilly; 43 USPQ2d 1398) upheld a federal court ruling that manufacture of recombinant insulin by Lilly did not infringe U.S. 4,652,525, " Recombinant bacterial plasmids containing the coding sequences of insulin genes," expiring in 2004, concerning proinsulin, and 4,431,740, both assigned to the University of California. The university had alleged patent infringement after Lilly switched in 1986 to manufacture of recombinant insulin as a proinsulin fusion protein in E. coli, with subsequent cleavage to form insulin. The CAFC ruled that U.S. 4,652,525 was invalid because, even though it did provide the amino acid sequences for the A and B chains and a method for isolation of human insulin genes, it did not provide the nucleotide sequence of the human cDNA (i.e., was not fully enabling).

This CAFC ruling set a precedent related to the requirement that patents contain a full “written description” or full disclosure of the invention, citing the university for not including the complete gene sequence involved, and invalidating a claim for a cell line expressing recombinant insulin. This CAFC ruling set the precedent (extending In re Deuel) that reporting of cloned DNA (cDNA) sequences is required to obtain protection for recombinant proteins, and that knowledge of the protein sequence does not make the cDNA sequence obvious. The CAFC also upheld rulings that 4,431,740 specifically only covered recombinant expressed proinsulin, not proinsulin expressed in bacteria as a cleavable fusion protein with subsequent cleavage to form insulin (Lilly’s prb method); and that Lilly was not infringing this patent.

A U.S. District Court had earlier ruled that the originally-used Lilly/Genentech “two-chain” manufacturing method did not violate University of California patents (UC vs. Eli Lilly, 39UPSQ2d 1225; S.D. Indiana 1995). This 1995 lower court ruling had caused public controversy by declaring that Dr. W. Rutter and Dr. H. Goodman, inventors of the university’s insulin patent, had used plasmid pBR322 for cloning, which the inventors denied. Use of this vector was at the time prohibited for biosafety concerns by the NIH Recombinant DNA Advisory Committee (RAC). However, this part of the court’s ruling was reversed on appeal and upheld by the 1997 CAFC ruling, with the court ruling that noncompliance with the totally voluntary (for those not receiving federal funding) NIH RAC guidelines was not material to patentability.

Trials: With immunogenicity a major issue, Humulin’s trials included analysis of 18,500 serum samples from 3,400 patients for immune responses to E. coli peptides.

Market: Total sales of the various Humulin formulations have been reported to be $1239.1 billion iun 2012; $1.249 billion in 2011; $1.089 billion in 2010;.about $1.02 billion in 2009; %1.063 billion in 2008; about $1.0 billion in 2007; ~$925 million in 2006; $1.005 billion in 2005; $997.7 million in 2004; $1.060 billion in 2003; $1.061 billion in 2002; $1.004 billion in 2001, $1.088 billion in 1999 (acheiving blockbuster status); $959 million in 1998; $936 million in 1997; $884 million in 1996; and $794 million in 1995.

Analysts with Friedman Billings and Ramsey (FBR) have projected total sales of $863 million in 2006, and $800 million in 2007.

In July 2005, at the time of the discontinuation of Humulin lented and ultralente formulations (see the Status section above), the two products had experienced a 70% drop in sales the past four years, and were being used by only about 66,000 patients.

The 2007 Average Wholesale Price (AWP) for Humulin R U-500 (by prescription) is $210.68/20 mL, 500 U/mL vial (10,000 U total) (Red Book, 2007). The 2007 AWP for over-the-counter (OTC; non-prescription) Humulin R is $36.19/10 mL, 100 U/mL vial; for Humulin N (isophane; NPH) Pen is $119.43 for five 3 mL, 100 U/mL pens; for Humulin 70/30 Pen is $119/43 for five 3 mL pens ($92.45 in 2004); for Humulin 70/30 is $336.19/10 mL vial; for Humulin 50/50, 10 mL vial is $36.19; and for Humulin U (ultralente), 10 mL, 100 U/mL vial is $33.20.

Humulin is the most popular brand of insulin worldwide. Over four million diabetics worldwide use Humulin daily. Novo Nordisk’s insulin products lead in international sales.

During May 2004, among the major insulin products (Humalog, Humulin, Novolin, Novolog, and Lantus) in the U.S. market, a total of 188,283 prescriptions were filled for Humulin (38.0% market share).

R&D: In Aug. 2004, Lilly announced it was advancing development of an inhaled formulation of insulin (AIR Insulin) being developed in collaboration with Alkermes, Inc. This followed promising results from a Phase II study; successful scale-up of the manufacturing process; and development and testing of the commercial pulmonary insulin inhaler system. In fall 2005, Lilly began a 2-year, open-label, international Phase III trial comparing AIR insulin vs. injected pre-meal insulin in 400 patients with Type I diabetes; and an open-label,12-month, international Phase III trial in 600 Type I and Type II diabetic patients with mild to moderate asthma or obstructive lung disease comparing AIR insulin vs. injected insulin.