dx.doi.org/10.14227/DT060399P16

Meeting Report:
"AAPS Workshop on SUPACs: Where are We
Going? Have We Reached the Limit?
David C. Pang
Director of Scientific Affairs, American Association of Pharmceutical Scientists

AAPS conducted a workshop on Scale-Up Post Approval Changes (SUPACs), March 15-16, 1999, Crystal Gateway Marriott, Arlington, VA. Some of the goals of the workshop were: 1) to review the scientific, regulatory and quality basis of SUPACs, 2) to assess if SUPACs are current with advancement in science and regulatory policy; and 3) to discuss successes and failures of SUPACs and current issues.

The SUPAC initiatives were started to provide scientific rationale to expedite the processes of post approval changes of drug products so that FDA can assure their safety and effectiveness and at the same time lower the regulatory burden for industry. Problem areas were identified and research was performed at academia, industry and FDA laboratories to support changes in 1) components and composition; 2) manufacturing (process and equipment); 3) scale of manufacture; and 4) site of manufacture. The specifications for the drug product include sterility, dissolution rate, containers and closure systems. It was the intent of the research to improve specification requirements and modify testing procedures for the product quality aspects of drug production. The changes may shorten the application process for industry and facilitate the approval process with the FDA.

Investigators at University of Maryland/Baltimore, FDA and pharmaceutical industry gathered data on the impact of scale-up, formulation, and other manufacturing changes on product quality, resulting in the release of a number of guidances by FDA, including: 1) Immediate release solid oral dosage forms, scale-up and post-approval changes: chemistry, manufacturing and controls, in vitro dissolution testing, and in vivo bioequivalence documentation (SUPAC-IR); 2) Modified release solid oral dosage forms, scale-up and post-approval changes: chemistry, manufacturing and controls, in vitro dissolution testing, and in vivo bioequivalence documentation (SUPAC-MR); 3) Semi-solid dosage forms, scale-up and post approval changes: chemistry, manufacturing and controls, in vitro dissolution testing, and in vivo bioequivalence documentation (SUPAC-SS), 4) Intermediates in drug substances synthesis/bulk actives post approval changes: chemistry, manufacturing, and controls documentation (BACPAC I) and 5) SUPAC-IR/MR manufacturing equipment addendum. Several other SUPACs are at various stages of development including one for transdermal delivery systems (SUPAC-TDS) and one for sterile aqueous solutions (PAC-SAS). As can be deduced, the guidances have been developed on the basis of types of dosage forms.

The guidances provide specific recommendations on documentation of equivalence in post approval changes of drug products in component-composition, batch size, manufacturing process and site of manufacture. Each category is divided into 2 or 3 levels based on the degree and type of changes in the approved product. Post-change product batch is considered the same as the pre-change product batch when there is no discrepancies in their dissolution profiles or the release rates. The similarity in the physicochemical properties of the batches from the release test or dissolution profile can be used to infer that the pre-change products and post-change products are also the same in terms of safety, efficacy or bioequivalence.

SUPAC-IR uses in vitro dissolution tests to indicate product sameness. Dissolution profile comparison on post-change batch and pre-change batch is indicated by the similarity factor, f2.

Log = logarithm to base 10
n = number of sampling time points
= summation over all time points
Rt = dissolution at time point t of the reference (pre-change batch)
Tt = dissolution at time point t of the test (post-change batch)

In vitro-in vivo correlation is an important measure for SUPAC-MR involving development, validation, application and dissolution profile comparison. In vitro release test is used in SUPAC-SS as a measure of product quality and sameness. The equivalence approach based on a standard confidence interval procedure is utilized to verify that the lots are close enough for product sameness between pre-change and post-change batches.

The International Society for Pharmaceutical Engineers (ISPE) collaborated with FDA to provide equipment equivalence lists which clearly define classes and subclasses of equipment by unit operation. The Equipment Addendum Guidance documents provide assistance for changes in equipment.

Further updating of the SUPACs is possible based on the approach delineated in FDAMA Section 116 to permit pre-approved supplements, change-being-effected supplements and annual report filings. The concept of SUPAC on drug product is being extended to drug substance (BACPAC I and II). The general approach works to achieve continuing pharmaceutical equivalence and bioequivalence after approval for NDAs and ANDAs, as well as other approved FDA products.

There were 1,039 SUPAC supplements submitted for generics and 263 for new drugs from 1995 to 1998. Immediate release and alternate site changes dominated the topics for SUPAC supplements with 582 and 431 submissions, respectively, for generic drugs and 142 and 66, respectively, for new drugs. Semi-solids and modified release dosage forms accounted for less than 30 submissions for both types of drugs during the three year period. Based on qualitative estimates provided by pharmaceutical company representatives, consulting experts, and the number of SUPAC-IR submissions during 1997, the Office of Planning and Evaluation, FDA, estimated savings for 1997 chemistry, manufacturing and control changes to be $70.7 million. The savings generated by SUPAC were realized through shorter waiting times for site transfers, more rapid implementation of process and equipment changes, more rapid implementation of batch size increase, production of fewer unmarketable stability test batches, and reduced stability tests and reduced administrative cost. For example, there was documentation that the times taken for one company in submissions and reviews of supplements on packaging and manufacturing were 600 and 111 months, respectively, before and after the adoption of SUPAC guidances.

Overall, several industrial representatives at the workshop stated that there were no major issues with SUPAC. The coordination at CDER was excellent. After the initial learning period, pharmaceutical companies and the review divisions and district offices of FDA were comfortable with the processes involved in SUPAC.

It was the consensus of the scientists at the SUPAC workshop that there are several issues that need to be addressed for future SUPAC applications. The topics that need to be addressed are dosage form independent issues, SUPAC IR/MR/SS issues, site transfer, and equipment process changes. Dosage form independent issues include multiple changes, packages, and sizes. SUPAC-IR/MR issues include: 1) mechanism to control changes to specification and in-process control; 2) capsules (size, shapes, color); 3) tablet weight; 4) shape, size, scoring, energizing; 5) need to simplify Case C dissolution; 6) product-specific selection of media; and 7) f2 specification/profile. Site transfer issues include:1) harmonization of IR/MR site transfer requirements for stability; 2) transfer of experiment date to new site, and 3) the need for a bioequivalent test for level 3 SUPAC-MR. Equipment process change issues include 1) the use of biopharmaceutical classification system to justify changes being effected (CBE) and 2) clarification of deposition of other types of level 2 and 3 changes. SUPAC-SS issues include preservatives and in vitro release testing.

As stated by Larry Augsburger, President of AAPS, the range of dissolution profiles of products found bioequivalent in the Maryland study may be broad enough to encompass many major changes. Consideration should be given to: 1) reducing the dissolution requirement for Class I drugs. For the examples studied, the requirement of 85% dissolution in 15 minutes was not justified, 2) reducing the filing requirements for a change in technical grade of excipient at least to CBE classification in accordance with 21 CFR 314.70(c). Though limited in the number and classes of excipients tested, the Maryland data do not support Level 2 (PAC), 3) shifting of levels downward by an increment of one for compositional changes, 4) removing reference to 10X in re scale changes, and 5) reducing the media required in Level C dissolution tests to two or three.