DPC and Immunodiagnostics
at the Threshold of a New Millennium

Michael L. Ziering
President and Chief Executive Officer

Since its beginnings in the late 1950s with the foundational work of Berson and Yalow, the technique of immunoassay has evolved dramatically to become an indispensable weapon in the arsenal of modern medicine for rapid, accurate diagnosis. Now in widespread, routine use, immunoassay has revolutionized medical practice and has proven itself as a cost-effective, and even in some cases life-saving, tool. Supplying a broad menu of quality immunoassays for clinical and research use has been Diagnostic Product Corporation's sole focus for nearly three decades. As the world makes the transition from one century to the next, from an old millennium to a new, it seems to me an appropriate time to reflect on the Company's contributions in the field of immunoassay as we rededicate ourselves to our tradition of responsiveness to customer needs.

A modest beginning
Incorporated in Los Angeles in December 1971, DPC initially manufactured tritiated reagents for cyclic AMP determinations and sold them to the National Institutes of Health and various other research organizations. The only other commercially available immunoassays at the time were those for T3 uptake, T4 and digoxin. Tritiated kits remained DPC's focus for a few years until it developed an iodinated folic acid assay; various thyroid hormone kits then followed. DPC assays gained greater market acceptance when the Company replaced its charcoal separation method with double-antibody separation.

Technological advantage brings rapid growth
In the late 1970s, DPC perfected its methodology based on iodinated tracers and double-antibody separation. One notable kit offered in this format was the first FDA-cleared urinary albumin immunoassay. DPC also developed a proprietary technique for coating tubes that allowed routine attachment of a wide range of antibodies. This technological breakthrough allowed the rapid development of a series of significant antibody-coated tube RIAs in the 1980s, including the first direct (no-extraction) assays for small fertility- related steroids. DPC's array of high-quality tests for reproductive hormones, which included highly accurate assays for peptides such as FSH and LH, secured the Company's dominance in this testing area.

In addition to assay quality and a dedicated and talented in-house team, strong alliances forged with various international entrepreneurs allowed DPC to become a significant supplier to markets in several major countries by the late 1970s. Today, with 22 international subsidiaries and an extensive network of overseas distributorships, DPC supplies nearly all major markets, covering over 100 countries. Manufacturing and R&D operations are located in Los Angeles, New Jersey, the UK and Germany, with additional manufacturing in China.

Allergy testing advances
In the 1980s, DPC developed a patented enzyme immunoassay methodology based on liquid-phase kinetics. DPC's AlaSTAT® allergy test systems employ this technology. Unique in the industry because of its use of liquid allergens, the AlaSTAT technology paved the way for full automation of high-volume allergy testing for the first time. Significant among DPC's numerous in vitro AlaSTAT allergen-specific IgE tests are the AlaSTAT in vitro tests for latex allergy released in 1995, the first commercially available for this growing public health problem.

Other important testing categories that DPC has supplied with RIAs and EIAs include endocrine function, infectious disease, drugs of abuse, therapeutic drugs and veterinary testing. The first commercial assays for canine TSH were the fruit of R&D efforts at DPC's Los Angeles and German sites. Though today's market trend is toward automated nonisotopic systems, DPC continues its support for RIA customers at a time when other manufacturers show little or no interest.

DPC has long allocated a significant percentage of its resources to an increasingly sophisticated R&D organization. Today, R&D encompasses state-of-the-art departments devoted to organic synthesis, biochemistry, protein chemistry, molecular biology, infectious diseases, antiserum development, monoclonal antibody development, technology development, and method development.

DPC launches automated immunoassay systems
In 1992, DPC made a decisive entry into the automated laboratory systems market with the acquisition of Cirrus Diagnostics Inc., a start-up company in New Jersey that had developed the IMMULITE® immunoassay analyzer. The IMMULITE system offered an advanced level of automation, and exquisite sensitivity achieved with a proprietary wash method and a novel chemiluminescent substrate. Within 18 months, DPC had developed for the IMMULITE the most complete menu available for any automated immunoassay system. DPC was the first to offer fully automated tests for third generation TSH, third generation PSA, free PSA, intact PTH, allergy screening, and cytokines. The system currently offers over 100 tests, with 70 of these cleared by the FDA for use in the US.

After the widespread market acceptance of the IMMULITE, DPC turned to the development of the high-throughput IMMULITE® 2000 system, which it released in 1998. Rapid adaptation of many existing IMMULITE tests—a task that continues alongside the development of new assays specifically for the IMMULITE 2000-has already resulted in a broad menu that allows laboratories to consolidate their testing on a single instrument. The IMMULITE 2000 system currently offers nearly 50 assays, with 35 of these FDA cleared for use in the US.

Support for customer education
DPC personnel and collaborators continue to give presentations around the world on DPC's assays and technologies. The Company has also sponsored several symposia on topics of current scientific interest, including the first international symposium on allergy and molecular biology in 1987, an international conference on PSA and prostatic disease in 1996, and luncheon symposia on a variety of current topics during the American Association for Clinical Chemistry (AACC) annual meetings. The AACC has recognized DPC as a significant supporter of that body's educational and scientific programs. In 1999, the AACC and DPC announced the establishment of a joint annual award to be conferred for an outstanding contribution for publication in the AACC's Clinical Chemistry journal.

Conclusion
Rapid advances in assay technology during the past three decades have precipitated many changes in the immunoassay industry. DPC has transformed itself accordingly and has expanded its range of products. No longer a company supplying only reagents, DPC today offers state-of-the-art automated devices complete with reagents and full technical support—a transition few other companies have been able to manage successfully.

Throughout its history, DPC has played a significant role in the evolving world of immunodiagnostics. The full benefits of in vitro diagnostic (IVD) testing have yet to be realized, however. This is true not only in developed countries where the desire for cost containment is, ironically, an obstacle at times to optimal use of IVD testing—the aging populations of these countries should make the case for such testing even more compelling—but also in less developed countries where expectations for improved healthcare run high. By developing immunoassays and automated systems of the highest quality, and through educational services, DPC continues to respond to market needs. Presently the only major worldwide company dedicated exclusively to immunoassay, DPC remains committed to meeting current and future needs as a pure-play immunoassay company.