Pharmacology Update
Pharmacology Update
The Latest Information on New Drugs and New Indications
The usually conservative merck pharmaceuticals has recently been pushing the patience of the FDA with some of its marketing practices. In June, the company was warned about its alleged practice of minimizing risk information for its products in its advertising. More recently, the company received a letter from the FDA challenging some of its marketing material for the company's new antileukotriene asthma medication, montelukast (Singulair). The FDA felt that some of the drug's advertising implied that it would be effective for exercise-induced asthma. And, although there is good evidence that the drug is useful in this role (N Engl J Med 1998;339:147-152), it has not been granted FDA approval for this indication. Until the indication is approved, Merck may not market the drug for exercise-induced asthma. Interestingly, the FDA's ability to enforce this regulation was the subject of a lawsuit filed by a public interest group in 1994. In July, a U.S. district court judge ruled that these limitations violated a drug maker's free speech. Eventually, this may lead to a liberalization of off-label marketing practices. The FDA is still deciding whether to appeal.
In other marketing news, one of the cornerstones of drug marketing, drug samples, is again under fire. An unsuccessful bill to ban sampling was proposed to congress and rejected in 1994, but there is renewed interest in the subject. Recently, an executive from the American Pharmaceutical Association suggested that sampling deprives patients of the ability to counsel with a pharmacist regarding the specifics of the drug. They propose a system of starter packs supplied by pharmacists with appropriate counseling as an alternative to sampling.
For aggressive marketing, it's hard to beat Novartis, the maker of fluvastatin (Lescol). To gain ground in the competitive cholesterol lowering market, they are offering patients who take Merck's lovastatin (Mevacor) a $10 rebate to switch to their drug. The offer is being handed out in pharmacies as patients pick up their medication. But, it may be Bradley Pharmaceuticals that has really discovered the ultimate marketing tool. They have a new freebie for physicians-Beanie Babies. The toys are given to physicians for writing prescriptions for their medication, Deconamine. Apparently, there has been a brisk response to their promotion.
Viagra has been approved for use in Europe for the treatment of erectile dysfunction. Coverage of the drug may vary from country to country. England's national health system has already indicated that it will not cover the drug and are concerned about Pfizer's pricing policy. Meanwhile, in this country, election year politics may play a role in getting the drug on managed care formularies. Fearing scrutiny from California's Department of Corporations, the agency that regulates HMOs, Kaiser Permanente in California has added the drug to its formulary. Some politicians had asked the DOC to look at Kaiser's policy of not paying for the drug, and several interest groups had filed lawsuits against the HMO.
The FDA has approved a new drug for the treatment of Crohn's disease. Infliximab (Remicade-Centocor) is approved for severe forms of the disease that are resistant to other more conventional treatments. The drug works by blocking tumor necrosis factor and is given parenterally in a single dose. The drug is particularly effective at reducing fistulas that are caused by the disease. Short-term effects of infliximab are impressive, but long-term outcomes have not been evaluated. Cost of a single treatment is nearly $1400.
While debate continues over the appropriate duration of therapy of tamoxifen for breast cancer treatment, a new role for the drug is emerging. Reported in the Journal of the National Cancer Institute (1998;90:1371-1388), a new study has shown a 49% reduction in the rate of breast cancer in high-risk women. The results were released more than a year early because of the strength of the data. Risk was determined by age, family history, personal history of abnormal biopsy, parity and age of first delivery, and age at menarche. Women on tamoxifen were more likely to develop endometrial cancer, DVT, and pulmonary embolism, with younger women at higher risk for these complications. The study also looked at the effect of tamoxifen vs. placebo on heart attacks (no change) and bone fractures (improvement but not reaching statistical significance).
The FDA has taken action on two new drugs for rheumatoid arthritis. On September 11, the FDA approved leflunomide (Arava-Hoeschst Marion Roussel). The drug is a disease-modifying agent that works by inhibiting dihydroorotate dehydrogenase, an enzyme linked to the proliferation of activated lymphocytes. It may be used for early stage or advanced disease. Leflunomide, which is supplied in three different strength tablets, should not be used by pregnant women or those planning pregnancy in the short term. The FDA's Arthritis Advisory Committee has also recommended approval of etanercept (Enbrel-Immunex), a drug that also works by inactivating tumor necrosis factor. Etanercept is a competitive inhibitor of the TNF binding site, blocking one of the significant inflammatory pathways in the disease. The drug, which is given parenterally, may be used alone or in combination with methotrexate.
The long awaited drug trastuzumab, generally known by its trade name Herceptin (Genentech), was approved by the FDA on September 25. Herceptin is a monoclonal antibody that targets the gene HER2 (human epidermal growth factor receptor2). An HER2 abnormality, causing overproduction of the gene and the protein it codes for, is found in about 30% of women with breast cancer and appears to promote growth of the cancer. Women with this type of cancer tend to be younger and have a more aggressive form of breast cancer. Testing for the HER2 mutation must be performed on a tissue sample of the tumor, since the drug is only approved for breast cancer patients who overproduce HER2. Herceptin is indicated for initial treatment of patients in combination with paclitaxel (Taxol-Bristol-Myers Squibb) and by itself for those who already have undergone other cancer therapy.
Two drug companies have announced that they have made significant progress in the development antivirals targeted against the influenza virus. Hoffmann-La Roche announced that their drug, GS4104, has been effective in clinical trials at reducing the duration and severity of flu symptoms. Based on results from phase III trials, the drug also seems to reduce the risk of serious sequelae of the flu such as bronchitis and pneumonia. The drug works by targeting viral neuraminidase, which is virtually the same in all common strains of influenza. Blocking neuraminidase inhibits the release of virus from infected cells. Glaxo Wellcome has been working on its own topical neuraminidase inhibitor, zanamivir. The drug is administered via a nasal inhaler. When used early in the illness, the zanamivir appears to be effective at decreasing the duration of illness. Both drugs are at least one year away from full FDA approval.
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