Of orphans and balloons.

The recent arrival on the market of a modified glucocerebrosidase (Ceredase) for Gaucher's Disease and last year's approval of PEG-adenosine deaminase for severe combined immunodeficiency disease illustrate the growing capabilities of the pharmaceutical industry to provide endogenous compounds that patients are lacking. These two biologicals/drugs have been designated as orphan drugs pursuant to the Orphan Drug Act of 1983. An orphan drug is defined as one used for the diagnosis, treatment, or prevention of a disease or disorder affecting fewer than 200,000 people in the United States. A drug can still be considered an orphan when its target population exceeds 200,000 if the sponsor cannot recoup the cost of development and marketing through sales of the drug in the United States. [1]

Both glucocerebrosidase and PEG-adenosine deaminase have limited target patient populations. However, the high cost of these biologicals and their potential for lifelong administration raise important issues regarding coverage. For example, the unit price for glucocerebrosidase is $3.50, with usual dosing ranging from 60 units per kilogram of body weight for initial therapy to as low as one unit/kg for maintenance. About one-third of the cases of Gaucher's Disease are diagnosed within the first decade, while the remainder are diagnosed during adulthood. During the initial treatment of a 60-kg adult, the costs could run as high as $12,600 every two weeks. Estimates of the annual drug costs for maintaining patients on glucocerebrosidase therapy range from $20,000 to $60,000. [2]

The cost of the PEG-adenosine deaminase biological is much more striking, in that annual replacement therapy is estimated to range between $100,000 and $350,000 per patient. [2] Fortunately, considering the severity of the disease and the great expense of treatment, the number of patients afflicted is much more limited than the 2,000-3,000 individuals with Gaucher's Disease. Notwithstanding the small number of patients, providing care to even one patient can have a significant financial impact.

Interestingly, these two biologicals are being marketed by biotechnology companies but are not recombinant DNA products. Rather, the marketed Ceredese is a modified placental-derived preparation of glucocerebrosidase, while the adenosine deaminase is bovine-derived. In fact, recombinant DNA technology may significantly reduce the costs of long-term maintenance therapy either through the development of recombinant substitutes or through specific gene therapy.

Moving from orphan diseases to the very common disorder BPH only serves to accentuate the financial implications of the introduction of new technologies. Even while the debate continues about the appropriate indications for transurethral resection of the prostate (TURP) versus watchful waiting in the management of BPH, new therapeutic options are being introduced. One of these is the application of balloon catheters for dilation (TUDP) of the urethra and bladder neck. This technology has been estimated to cost about $3,000 per procedure, as opposed to $6,500 to $10,000 for a TURP. [3] The introduction of this technology has been greeted by general disagreement within the urology community over the effectiveness of the dilation procedure. This is clearly illustrated by the conclusions of studies presented at the 1991 annual meeting of the American Urological Association.

For example, Lepor et al. [4] conducted a small randomized control trial comparing cystoscopy to TUDP in the management of BPH. After finding statistically significant improvement in sympton scores in both groups but no improvement in peak urinary flow, the researches concluded that "the present study indicates that the previously observed efficacy following BDP [TUDP] is primarily related to a placebo effect." In a meta-analysis of 150 studies with over 50,000 patients, Roehrborn et al. [5] concluded that "the degree of improvement represents the percent decrease in sympton scores and indicates the superiority of surgical treatment options in this regard." De Geeter et al. [6] concluded from their study of 22 patients that TUBD [TUDP] is a rather inefficient method to alleviate the outflow obstruction secondary to benign prostatic hypertrophy."

On a more positive note, Cherry et al. [7] concluded that "in the well-informed patient, TUDP is a viable option because of its simplicity, safety, and no or minimal hospitalization." Other investigators assumed more of a "wait and see" posture, emphasizing the need for studies with long-term follow-up and the value of identifying specific subpopulations of patients (e.g., prostate size less than 40 grams; lack of median lobe enlargement; etc.)

It appears that the limitation on balloon dilation in BHP will parallel that observed for balloon angioplasty. The problem with reobstruction seems to be a significant occurrence, as illustrated by a study by McLoughlin et al. [8] In this study, only 13 of 27 patients who presented with bladder outflow obstruction and were dilated remained unobstructed at 3 months and only 3 of the 27 patients remained unobstructed at 6 months. At six months, 15 of the 27 patients indicated that they remained symtomatically improved, however.

Thus, while some suggests that balloon dilation offers a less invasive, less expensive alternative to TURP, the issues of reobstruction with redilation and/or progression to the surgical option are concerns that must be addresses by further study. When faced with a $3,000 dilation potentially followed by a second dilation with progression to TURP, the need for convincing effectiveness data is highlighted. For the 400,000 or so patients with BPH, the therapeutic options continue to increase. For those charged with the efficient management of health care services, the complexity of management decisions increases proportionately.

The orphan drug and balloon technologies discussed here illustrate the significant impact that very expensive, very low volume technologies and high volume, "cost saving" technologies might have on an individual plan. As those involved in making coverage and benefits decisions address these and other pressing issues, they can "rest" assured that the continued development of new technologies will keep their decision-making skills finely honed.

References

[1] Bennett, D., Editor. AMA Drug Evaluations. Chicago, Ill: American Medical Association, 1990.

[2] Werble, C. Pink Sheet, 53(15):12-4, April 15, 1991.

[3] "Will New Therapies Reduce Prostate Surgery Frequency." Health Technology Trends 3(6):7-8, June 1991.

[4] Lepor, H., and others. Presentation at 1991 Annual Meeting of the American Urological Association, Toronto, Ontario, Canada.

[5] Roehrborn, C., and others. Presentation at 1991 Annual Meeting of the American Urological Association, Toronto, Ontario, Canada.

[7] Cherry, R., and others. Presentation at 1991 Annual Meeting of the American Urological Association, Toronto, Ontario, Canada.

[8]McLoughlin, J., and Williams, G. "Alternatives to Prostatectomy." Bristol Journal of Urology 67:316-6, April 1990.

William T, McGivney, PhD is Head of New Technology Assesment, Aetna Heath Plans, Hartford, Conn.