FDA’s DRUG REVIEWS WELL-MANAGED, PMA SAYS, BUT ASSOCIATION IS CONCERNED WITH BUILDING BACKLOG AT BIOLOGICS; BIOTECH IND APPLICATIONS INCREASING

FDA's 1991 new drug approval record indicates that the Center for Drug Evaluation and Research is processing NDAs expeditiously, the Pharmaceutical Manufacturers Association says. The association, however, has a new concern about a regulatory backlog developing in application reviews by the Center for Biologics Evaluation and Research. At a Jan. 15 press briefing, PMA Exec VP Robert Allnutt praised FDA for both the total of 30 new compounds approved by the agency in 1991 and the average time in which they were reviewed. Although the 30.3-month average review time last year was 2.6 months longer than in 1990, Allnutt said the "increase was caused by FDA's efforts to reduce the backlog of long-pending NDAs." Four new chemical entities approved by the agency in 1991 "had been at FDA five to eight years or more, which drove up the average approval time considerably," the PMA exec noted. "If we omit the four long-pending drugs from the calculation of average review time, the remaining 26 new drugs were reviewed and approved in less than two years." Furthermore, he added, five new drugs for life-threatening illnesses like AIDS and cancer were cleared in less than a year and another seven in less than 18 months. Congratulating Commissioner Kessler for the agency's record review performance, Allnutt gave particular credit for the improvement to CDER Director Carl Peck, MD, and Deputy Director Gerald Meyer. As CDER's "top managers," Peck and Meyer, "for years have worked hard to make the drug approval process more efficient," Allnutt said. "And, as Dr. Kessler has graciously acknowledged, some of the reforms that enabled the improvement this year in FDA's performance were initiated by his predecessor, Dr. Frank Young." PMA Senior VP-Science & Technology John Beary, MD, told the briefing that part of FDA's record 1991 performance can be attributed in part to two industry-government initiatives: the use of computer-assisted NDAs (CANDAs) and NDAs. "Eleven of the 30 new drugs approved [in 1991] included the use of" CANDAs, Beary noted. "Considering that NDAs can consist of 100,000 pages of data or more, it is easy to understand how computers can greatly expedite the location, retrieval and analysis of data and reduce the massive paper burden at FDA." Beary added that a total of 30 NDAs using CANDAs have been approved to date and that 65 CANDAs have been submitted to FDA as of Nov. 30, 1991. "More than half of them were submitted during the past three years," he pointed out. The reviews of two new compounds approved in 1991 included "NDA Days," during which "FDA officials responsible for... later stages of review and key representatives of pharmaceutical companies are brought together" in "an intensive one-day session" to answer questions regarding an NDA. Beary said that PMA believes that "NDA Days are a valuable initiative and hope FDA will expand their use." Allnutt also pointed out that FDA approved 28 "important" new uses for already marketed products through NDA supplements in 1991. The "efficacy supplements" included indications for cardiovascular disease, cancer and gastrointestinal bleeding, he said. The 28 supplemental indications were among 43 efficacy supplements FDA cleared last year for new uses and dosage forms of previously marketed products. The agency also approved 10 new dosage regimens, four Rx-to-OTC switches (Monistat-7 and Mycelex- G, each in two dosages) and one label change to include a new patient population (pediatric labeling for Alupent). CDER approved a total of 1,342 labeling supplements, which included minor changes or additions to indications, labeling or manufacturing of previously marketed products. On a less enthusiastic note, Allnutt pointed out that FDA's Center for Biologics Evaluation and Research "approved only eight biologics -- three therapeutics, two vaccines and three diagnostics." Only two biologics approved last year, which are indicated for cancer-related conditions, are genetically-engineered products, Allnutt observed. "CBER needs to better manage its increasing backlog of genetically-engineered medicines if this advanced technology is ever to reach its full medical potential," he said. PMA reports that 132 genetically-engineered medicines are in development, 21 of which are pending at FDA. A backlog in FDA reviews of biotechnology products could be exacerbated in upcoming years with the onslaught of applications involving cutting-edge technology, such as gene therapy. Gerald McGarrity of Gene Therapy, Inc., and previously head of the National Institutes of Health's Recombinant DNA Advisory Committee, told a Jan. 15 session of the BioEast'92 conference in Washington, D.C. to expect "a tripling or quadrupling of protocols" to study genetic alteration treatments within the next few years. FDA is aware of the upcoming applications and is trying to iron out policy questions prior to the arrival of the first influx of gene therapy applications (see following story). W. French Anderson, MD, a researcher at the National Heart Lung & Blood Institute and an acknowledged pioneer of gene therapy, told the BioEast conference that there have been 11 approved gene protocols, six involving gene transfer and five gene therapy. Current clinical trials involve 24 patients -- 22 in the U.S., one in France and one in China. Noting the 11 ongoing protocols, McGarrity said: "Knowing what is going on in the pipeline, there are probably a doubling of this number being written or in the process of being submitted to either FDA or NIH." Therefore, he continued, "it is probably a safe bet to say that in the next one to two years, we'll probably see a tripling or quadrupling of protocols coming before these various committees." He reasoned that "once you present a concept of this to bright and innovative people, they will find a whole variety of ways of trying to solve their own basic and clinical science problems and trying to treat patients more effectively, especially if alternative therapy does not exist." At a Feb. 10-11 meeting, the NIH advisory committee is scheduled to consider an amendment to the NIH gene therapy protocol for adenosine deaminase (ADA) deficiency that would add infusions of genetically-modified peripheral blood stem cells transduced with the ADA gene. Anderson, one of the study investigators, told the BioEast conference that the ADA protocol amendment "will be the first stem cell gene protocol" to be reviewed by the committee. Anderson wrote in a Jan. 10 memo with principal investigator Michael Blaese, National Cancer Institute, to Office of Recombinant DNA Activities Director Nelson Wievel that the "amendment offers a distinct possibility for additional therapeutic benefit while increasing the risks minimally." FDA approved Enzon's Adagen, the sole ADA deficiency therapy marketed in the U.S., in March 1990. Therapeutic benefit of the protocol would be improved by infusing "gene-corrected hematopoietic progenitor cells (including totipotent stem cells) that should: last longer in the patient, divide to give a broader range of corrected cells, [and] produce pre-T cells that can be educated," i.e., healthy pre-T cells capable of responding to new antigens, Blaese and Anderson asserted. PMA's Allnutt projected industry R&D investments of $10.9 bil. for 1992. The total will exceed by $1 bil. the total R&D investment of the U.S. drug manufacturers during 1991 and is "more than double what they invested just five years ago," he said. The increase will represent a 13.5% jump over the drug industry's R&D spending during the previous year, he added, and compares with a 1% R&D investment increase for U.S. industry overall.