Immunex is building its first internal Enbrel sales force in preparation for etanercept's sBLA approval for psoriatic arthritis, Commercial Operations General Manager Mark Booth announced Aug. 20 during the company's R&D update in Seattle.

"Immunex is going to be entering the sales force game and putting together a sales force to promote Enbrel," Booth told analysts. The sales force, which will consist of less than 100 reps, "will be up and running early in the first quarter of 2002."

The sales reps will play two roles, Booth said. First, "they'll help double-cover the most productive, upper decimal rheumatologists" with copromotion partner Wyeth-Ayerst. Enbrel is currently approved for rheumatoid arthritis, juvenile RA and early RA.

"But more importantly, this will be the group that will provide coverage to the dermatologists in anticipation of our psoriatic arthritis approval," the exec said.

While about two-thirds of psoriatic arthritis patients are treated by their rheumatologists, dermatologists "are extremely important in the referral network," Booth said. After the anticipated psoriatic arthritis approval, "dermatologists will become much more active in actually treating these patients."

Immunex estimates there are approximately 1,000 dermatologists actively prescribing methotrexate. "Those will be the primary targets that we go after because we're highly confident that they're treating psoriatic arthritis right now in some shape or form."

The company filed an sBLA for psoriatic arthritis in July; if FDA grants the application a priority review, the indication could be approved in the first quarter of 2002. Immunex estimates there are 300,000 psoriatic arthritis patients for which Enbrel would be appropriate.

"We're in the process of designing that sales force as we speak. We'll be recruiting and training at the end of this year and expect to have this group up and running early in the first quarter," Booth said. "This is just the first of many sales force expansions you're going to see on this product."

Immunex' sales reps will add to Wyeth's existing sales force, which was realigned and expanded by 20 specialty reps in April. As a result, Enbrel captured the leading share of voice in the RA market in April, May and June, Booth said, citing IMS Health data.

Another Enbrel promotional tool, RA Access, was launched via an unbranded direct-to-consumer television commercial in July (¹ [A#00630300021]). Through a toll-free number and at www.ra-access.com, patients can receive information about rheumatoid arthritis.

While initial information will be about the general disease, Immunex will "nurture this patient group along, giving them more and more Enbrel-specific messages as we move closer" to completion of the manufacturing facility in Rhode Island, Booth said.

Immunex hopes to get 200,000 patients signed up on RA Access by July 2002. In the four weeks since the commercial broke, 23,000 patients have enrolled in the program, Booth said.

The company is also continuing to add patients to the Enbrel Enrollment program. About 800 to 1,000 patients have been added to the waiting list each week for the last two months, Booth noted.

At the same time, Immunex has been rotating about the same number of patients off the Enbrel wait list as additional supply becomes available or existing patients stop therapy. Therefore, there are virtually no patients on the waiting list, Immunex said.

"We've been able to offer...17,000 patients access to Enbrel since April," the exec said. Immunex expects to increase the total number of patients on therapy from 69,000 in the first quarter of 2001 to 81,000 in the fourth. Enbrel is currently used in about 75,000 patients.

Estimating there are 1 mil. rheumatoid arthritis patients in the U.S., 80,000 patients equals an 8% share, Booth calculated. With the appropriate supply, Immunex estimates that Enbrel could eventually capture a 25% share of the RA market.

Analysts appeared skeptical of Immunex' 1 mil. RA patient calculation and asked for assurance that the population existed.

While acknowledging that not all patients would initiate RA therapy on Enbrel, Booth maintained: "We've sanity-checked the 1 mil. patient number quite a few different ways and we're very confident there are 1 mil. solid patients out there in the U.S. that would be good candidates for Enbrel."

Immunex stressed that the Enbrel supply issues would not translate into flat sales in advance of the third quarter of 2002, when the first phase of the West Greenwich, R.I. manufacturing facility starts producing extra capacity.

"I really want to dispel this notion of no growth in Enbrel until Rhode Island comes on," Chief Operating Officer Peggy Phillips said. "There are two pieces that are as critical or perhaps more critical to us as we look to next year."

Process improvements at Enbrel contract manufacturer Boehringer Ingelheim's facility are expected to increase batch yield 10%-30%, Phillips said. While Immunex initially expects to achieve the lower end of the range, "as we go into next year and...continued use of this process, we'll see if we push that up higher than that," she added.

A second-generation process to be implemented later will improve Enbrel yield by two- to three-fold.

Immunex also has right of first refusal for production runs freed up by other clients of BI. "We have a right to get access to openings that are made from other products so that those can be assigned to us for Enbrel production," Phillips said.

"Looking at timing of our schedule,...for a year like next year, we're going to want as many of those runs as early in the year as possible."

"It's also possible as BI looks at their own schedule for their own products [and] that can adjust whatever that allocation is," she said. "We'll be looking at whatever additional capacity BI may be able to facilitate so that we can capitalize on the potential of additional runs."

While the Rhode Island plant will start producing additional capacity in the second half of 2002, "the majority of supply for next year is going to be driven" by Boehringer Ingelheim, Phillips noted.

Immunex has completed the process improvement runs at the Rhode Island site and expects FDA approval by the end of the year. A second phase, the BioNext Project, will add a 500,000 square feet facility; FDA approval is expected in 2005.

In addition, Enbrel partner American Home Products is investing $1 bil. in a biopharmaceutical production site in Grand Castle, Ireland. The first phase will be completed in 2005, with the second online a year later.

Enbrel production capacity is expected to be able to support between $900 mil. and $1.3 bil. in sales for 2002, Phillips said. The capacity should reach $1.8 bil. in 2003.

Enbrel should hit $4 bil. in sales in 2005, generating 80% of estimated. Immunex net sales of $5 bil. in 2005, Phillips explained. For the first half, sales were up 21% to $347.5 mil. and are estimated to be $750 mil. in 2001.

To reach the $4 bil. sales goal, Immunex is working on four new indications for Enbrel, including the one for psoriatic arthritis.

Outside RA, "there are close to 2 mil. patients that could benefit from Enbrel...based on data that we have that's either from the approval stage to what we're looking at with Phase II data," Phillips said.

Enbrel is in Phase II for psoriasis, which Immunex estimates affects 500,000 patients, and ankylosing spondylitis (150,000 patients). Immunex is also conducting Phase II/III studies for Wegener's granulomatosis (10,000 patients).

Immunex announced preliminary Phase II data for psoriasis during the R&D update. In the study, 112 patients with moderate to severe plaque psoriasis received either 25 mg Enbrel or placebo twice a week for six months.

At 12 weeks, 30% of Enbrel patients scored a 75% improvement or higher on the Psoriasis Area and Severity Index, versus 2% of patients in the placebo group. After six months, roughly 50% of the etanercept group scored a PASI 75 or higher, compared to 5% of the placebo arm. In addition, 20% of Enbrel patients improved by at least 90%.

Mild infections were the most reported adverse events in the first 12 weeks: 46% of etanercept patients reported infections versus 24% of placebo patients.

Data from two Phase II/III studies in Wegener's granulomatosis is expected in 2003. Immunex will begin Phase III studies for ankylosing spondylitis in 2002.

Immunex Enbrel Building Sales Force For Psoriatic Arthritis Approval

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