New monoclonal antibody agents face uphill battle for commercial success

Are long FDA review times making products too expensive?

The nuclear medicine community appears cautious in its attitudeabout the new radiopharmaceuticals just entering or about to enterthe U.S. market: Verluma, Myoscint, CEA-Scan, and ProstaScint.Early experience with OncoScint, the community's first monoclonalantibody agent, has caused concern about the effectiveness ofthis new breed of imaging agent. Meanwhile, a second concern --price -- has become as important.

All agents that pass the Food and Drug Administration's reviewprocess must at least have the potential to be effective. Theydo not have to be cost-effective to be approved. CEA-Scan, whichofficially entered the market a week ago, is fighting an uphillbattle in that regard.

"At $850 a shot, you wait and see what other people sayabout how good it is," said Dr. Carol Marcus, director ofthe nuclear medicine outpatient clinic at Harbor-UCLA MedicalCenter in Torrance, CA.

Marcus may not have long to wait. Mallinckrodt Medical of St.Louis, which has licensed the product from Immunomedics of MorrisPlains, NJ, has begun selling CEA-Scan as it prepares to launcha major mail campaign to alert U.S. physicians to the agent'savailability.

"We are doing what we call a controlled launch," saidDr. Carl Pinsky, vice president of medical affairs at Immunomedics."We want to assure ourselves that even the initial uses atany given site will be top quality so there will be repeat usageby referring physicians."

This cautious approach is grounded in the experience of Cytogenof Princeton, NJ, and its OncoScint CR/OV product, which has performedbelow market expectations since its debut in 1993 (SCAN 1/27/93).Part of the problem is due to varying results by users. An effortto understand the product's lackluster sales history led the companyto conduct 1100 overreads of OncoScint scans done by clinicians.The results indicated that half had been incorrectly interpretedand about 20% were inappropriately acquired or had poor countdensity.

In an effort to turn the market around for OncoScint, Cytogenlast year launched its Partners in Excellence (PIE) program, whichtoday includes about 40 clinical sites providing technical support,collegial interpretation, assistance with reimbursement issues,and other aids. That effort has returned only modest results.

"We haven't fixed the problem with OncoScint," saidPam Murphy, the company's vice president of strategy and communications."(If we had), the product would be bigger."

Cytogen will not make the same mistake if and when the FDAclears its newest agent, ProstaScint, which has received a favorablerecommendation from an FDA advisory panel and now awaits a finaldecision by the agency (SCAN 7/31/96).

"We've learned from OncoScint that you must support theproduct with a rigorous quality assurance process, which is whatour PIE program is all about," Murphy said.

Cytogen plans to expand the PIE program to support ProstaScintas part of a co-marketing agreement to be implemented with CRBard, which will target its efforts on urologists. By the timeof the product's launch, between 60 and 100 PIE sites will beoperating, with a final target of 300.

Immunomedics and Mallinckrodt are similarly determined to avoidthe problems encountered with OncoScint. CEA-Scan obtained regulatoryclearance for colorectal applications earlier this year aftera regulatory nightmare, during which advisors initially expressedreservations about the approvability of the agent (SCAN 7/17/96).Immunomedics and Mallinckrodt are not likely to have anywherenear the challenge faced by Cytogen.

"Actually, CEA-Scan is pretty easy to use," Pinskysaid. "But what we want is from the first usage to be asclose to optimal as possible, so we're trying to make sure everyoneknows even the simple things about it."

In the wake of the OncoScint disappointment, no one is takingchances. Du Pont Merck Radiopharmaceuticals in North Billerica,MA, has assembled a force of about 20 clinical specialists toteach nuclear medicine staff how to use Verluma, the new agentit has licensed from NeoRx for U.S. sales. Cynthia Franklin, directorof the new products group at Du Pont, described Verluma as a nicheproduct.

"We recognize that up front," Franklin said. "Itis a small product but it definitely fits a need within the medicalcommunity."

The company plans to approach two distinct groups with informationabout the product: nuclear medicine practitioners and referringphysicians who specialize in small-cell lung cancer.

Companies with new imaging agents are universally downplayingthe market potential of their products. Paul Wulfing, treasurerof MoAb pioneer Centocor of Malvern, PA, is enthusiastic aboutthe prospects for the company's new cardiac radiopharmaceutical,Myoscint, but that enthusiasm ebbed when he spoke about marketspecifics.

"We wouldn't necessarily define it as having great potential,"Wulfing said.

One company that is unabashedly bullish on its products is Diatideof Londonderry, NH. The company has five peptide-based agentsin clinical trials. These agents, dubbed techtides because theycombine technetium with peptides, are being groomed for imagingtumors, thrombi, atherosclerosis, and infectious diseases.

Ron Kinder, Diatide executive vice president of sales, marketing,and business development, believes the problem with the currentwave of targeted agents is their price tags. He points to OctreoScan,Mallinckrodt's peptide-based product targeted at neuroendocrinetumors.

"The biggest problem is price: $800 a dose," he said."

Bumping up that price is the cost of indium, which is more expensivethan the technetium used in Diatide's agents. As all Diatide agentsare linked to this radioisotope, they should have an edge in themarket -- when they get there."

Regardless of the isotope, however, the cost of these productsis not likely to fall much below the $300 to $400 range. CEA-Scan,for example, uses technetium, the least expensive of any imagingisotope at$850 a dose.

What's driving the cost of these agents is the long developmentcycle, including extensive clinical trials and the FDA regulatoryeffort needed to reach market.

"That basically tells us that the absurd cost of gettingthrough the FDA is rendering our drugs too expensive to buy,"UCLA's Marcus said. "Enormous changes have to occur in theway the FDA reviews our drugs or we need to take the drugs awayfrom the FDA entirely and have them reviewed by another group."

Several companies are trying to get more bang for their investmentby expanding applications for approved products. Immunomedicsultimately would like to get CEA-Scan approved for use in otherindications. Some phase II trials have been completed.

"We think the data are very good," Pinsky said. "Weintend to present these data to the FDA and hopefully they'llguide us as to the best way to get other indications approved."