Accounting for Lot-to-Lot Variability of Biologics in Biosimilar Development

In creating the 351(k) US biosimilar approval pathway, regulators had laid out a methodology in which the totality of evidence is weighted heavily by proof of structural and pharmacologic comparisons of the biosimilar to the originator product (unlike the most critical role of clinical trials in the conventional 351(a) regulatory pathway). Through the initial approvals by the Food and Drug Administration (FDA), the level of scrutiny given to these physical, pharmacodynamics, and pharmacokinetic evaluations has become clearer.

In its latest draft Lee 2guidance, the FDA has added some more direction, as well as emphasizing one of the key points of the biosimilar and biologic manufacturing process. They spotlight the level of variability of one biologic. Recognizing the potential for variation in one reference biologic, the 351(k) approval criteria include comparisons versus copies of the US-licensed (rather than EU-licensed) originator product. For some approvals, bridging studies, which also test the similarity of the EU- and US-licensed biologics, have been permitted. In the guidance, “Quality Considerations in Demonstrating Biosimilarity of a Therapeutic Protein Product to a Reference Product,” released earlier in September, the FDA further amplifies this requirement.

In the biosimilar development process, a prospective manufacturer must obtain samples of the biologic from the originator drug maker. However, as has been well documented, lot-to-lot differences in the biologic may well occur, though these are not expected to have implications for clinical safety or effectiveness. Proving structural similarity to this agent goes a long way to progressing down the path to approval. In its draft guidance, the FDA seems to expand its test for analytical similarity. The biosimilar manufacturer must obtain “a minimum of 10 reference product lots” and these lots “should represent the variability of the reference product,” against which the biosimilar drug is evaluated to allow for meaningful comparisons. In other words, the biosimilar manufacturer must consider the likelihood of variation in the local source of the biologic. The FDA is accepting public comments on its draft guidance for 60 days.

This has some basic implications for biosimilar manufacturers. To begin the process of engineering a biosimilar drug, they must obtain samples of the originator product from its manufacturer. This has not always been simple, as the drug maker defending its brand can delay the process or otherwise make it difficult to purchase. Some legislative proposals have been introduced to coerce the originator manufacturer to provide, in a timely manner, the samples required by the prospective biosimilar drug company (e.g. Fair Access for Safe and Timely Generics Act of 2017).

Action at the Capitol to Improve Access to Biologic Samples by Biosimilar Developers?

The Trump Administration has indicated a desire to streamline marketplace rules to improve the efficiency of the Food and Drug Administration (FDA) and to enhance manufacturers’ access to the marketplace. “President Trump issued an executive order to this effect,” said Mary Jo Carden, RPh, JD, Vice President of Legislative and Pharmacy Affairs, Academy of Managed Care Pharmacy (AMCP). But “what that means is still a question.”Image result for Mary Jo Carden

Efforts are underway to clear away a roadblock to manufacturers who are trying to bring a competitive biosimilar to the marketplace. Step 1 in the process of building a biosimilar, before a drugmaker can begin to develop and characterize a biosimilar version of an originator, is to obtain samples of the licensed biologic. This is not as simple as it sounds. Those companies producing the originator may be unwilling to provide samples or charge extremely high rates for the use of their product, as a way of stalling competition. Some manufacturers have used REMS and internal distribution restrictions as a reason not to sell to biosimilar drug developers.Image result for US Capitol

Reginia Grayson Benjamin, JD, Director of Legislative Affairs for the Academy, said that two separate initiatives are being developed in Congress to address this problem. First introduced in June 2016 by Senator Patrick Leahy (D-VT) (S. 3056), the Creating and Restoring Equal Access to Equivalent Samples (CREATES) Act, will need to be reintroduced in 2017. It is an effort to assist competition in the biologics market, by facilitating entry of biosimilars (and small-molecule generics). The CREATES Act,” according to Ms. Grayson Benjamin, “seeks a legal solution to the sample access problem, by creating a right to a civil cause of action for failure to provide sufficient quantities of a covered product.”

Second is the Fair Access to Safe and Timely Generics (FAST) Act, which may be reintroduced into the House of Representatives. It was first brought to Congress in June 2015 by Representative Steve Stivers (R-OH) as H.R. 2841, and did not make it out of the Subcommittee on Health. Ms. Grayson pointed out that it is not a companion to the CREATES Act, but it “would create a regulatory solution,” she said.

However, these proposals, which have not yet been formally debated or sent to committee, and other health care–related bills that have been introduced, have received little consideration because of actions surrounding and the ultimate vote to reject the American Health Care Act.

UPDATE: On April 6, H.R. 2051 was introduced in the House by Representative David B. McKinley (R-WV). This is a reboot of the FAST Act, and has been referred to the Referred to the House Committee on Energy and Commerce.