Taxotere vs. Taxol

Taxol and Taxotere are the drug label names of two separate but closely related chemical compounds. Both are used as chemotherapy drugs to treat various kinds of cancer. Taxol is the name under which the drug paclitaxel is sold, while Taxotere is a rebranding of the drug docetaxel. Both of these drugs fall under the category of “taxanes,” which is a class of chemicals derived from the bark of the Pacific yew tree. They only differ at two points in the chemical compound and have highly similar effects on the body. Both attack the cytoskeleton of the cell, weakening the cell's structure and preventing it from successfully replicating. This shared aspect of the compound makes it an effective chemotherapy drug because it kills cancer cells, which divide often. Since the two drugs are so similar, many people have questions about why one drug might be prescribed or recommended over the other. The differences are subtle and, unfortunately, there is no clear answer as to which drug is “better” or more effective. The following information provides a general overview of some of the drug's primary differences and a sampling of research which has performed direct comparisons between Taxol and Taxotere.

Differences in Development and Production

Both Taxol and Taxotere are approved for use in the treatment of multiple forms and stages of breast cancer. Paclitaxel (Taxol) was originally approved by the FDA in 1992 for the treatment of ovarian cancer, and, just two years later, it was approved for the treatment of breast cancer as well. Unfortunately, although Taxol was a particularly effective new drug with a lot of potential, it could originally only be extracted from the bark of the Pacific yew, which was harvested in large swaths to keep up with demand for the drug. When the bark of the tree was harvested, the entire tree would die, which was a problem because yews are particularly slow-growing trees. There were simply not enough specimens to keep up with demand for the drug.

Because of this shortage, researchers worked to develop a form of the drug which could be produced without relying on the natural resource. Out of this research, Taxotere (docetaxel) was created, which could be produced completely synthetically. Today, however, the production of Taxol does not depend on the population of Pacific yew trees. Taxol (paclitaxel) is now produced through a process called semisynthesis.

Semisynthesis is a kind of partial synthesis. This means that the process still initially depends on a naturally occurring compound, but chemists can synthesize the additions necessary to create the complete compound. In the case of Taxol, the initial compound is isolated from the European yew, which can be grown in Michigan more quickly than the Pacific yew. Once the compound is extracted and purified, the semisynthesis can be performed in a lab to add the final chemical group and complete the drug's production. Shifting dependence from the Pacific to the European yew, which can be produced commercially, has greatly increased Taxol's widespread availability.

Choosing between Taxotere and Taxol

While it is helpful to understand why both drugs were developed, many people now ask, what the medical difference between paclitaxel (Taxol) and docetaxel (Taxotere). Often, women with breast cancer are given the choice between multiple chemotherapy treatments available. Different oncologists may recommend competing therapies, and it can be difficult for patients to make a decision when there is no clear rubric to help them decide. A doctor can help a patient to weigh the pros and cons between two or three drug combinations, but, in the end, a patient has to commit to one course of treatment. Having all the available information about the risks and benefits of each drug is essential to making a personal and empowered decision.

Carrying Solution

One major difference between Taxol (paclitaxel) and Taxotere (docetaxel) is the solution in which these two chemicals are dissolved for infusion into the body. Taxol is dissolved in polyoxyethylated castor oil and alcohol, while Taxotere is dissolved in polysorbate 80 and alcohol. If a patient has an allergy to either castor oil or polysorbate, their doctor will most likely recommend the alternative drug.

Effectiveness

There is contradictory and competing evidence concerning the comparative effectiveness of Taxol and Taxotere. Early studies indicated that Taxotere might be more aggressive and successful at eliminating cancerous cells in the body because the drug could infiltrate the cell at higher levels than Taxol. However, this was merely a hypothesis at the time that Taxotere was released on the market, and long-term studies have not corroborated this initial indication. Both paclitaxel (Taxol) and docetaxel (Taxotere) are highly effective at treating breast cancer, and both work by attacking the skeletons of cells, preventing them from dividing.

Multiple long-term studies have proven that there is no statistical difference in survival rates between Taxol and Taxotere for the treatment of breast cancer that has spread to the lymph nodes or presents the risk of spreading. One study, in particular, published in the New England Journal of Medicine in 2008, included 5000 women and lasted nearly ten years. The study had four groups. One group was given paclitaxel (Taxol) weekly, one was given paclitaxel (Taxol) every three weeks at higher doses, one was given docetaxel (Taxotere) weekly, and the last was given docetaxel (Taxotere) every three weeks.

After monitoring the patients for years and recording the women's side effects and rates of recurrence, researchers concluded, “We found no significant differences in survival between the groups treated with paclitaxel and those treated with docetaxel or between the groups treated weekly and those treated every 3 weeks.” In fact, the exact numbers for 5 year survival for each of the four groups were nearly identical: “86.5% for the group receiving paclitaxel every 3 weeks, 89.7% for the group receiving weekly paclitaxel, 87.3% for the group receiving docetaxel every 3 weeks, and 86.2% for the group receiving weekly docetaxel.” As these numbers indicate, if anything, the weekly administration of Taxol seems to have a slight edge over all other combinations.

FDA Intervention

About a year after this study was published, the Food and Drug Administration (FDA) sent a letter to Sanofi-Aventis, the manufacturer of Taxotere, telling them that their claims about Taxotere's superiority in marketing materials for hospitals, doctors, and patients were unsubstantiated. The FDA cites a clinical trial sponsored by Sanofi-Aventis which evaluated the efficacy of Taxotere. While Taxotere performed better than non-taxane drugs, it was not directly studied in comparison to paclitaxel (Taxol). Sanofi-Aventis was still disseminating materials claiming that “docetaxel is superior to paclitaxel” in time to disease progression (TTP).

The letter sent to Sanofi-Aventis clearly states the company's violation: “Promotional materials are misleading if they contain a drug comparison that represents or suggests that a drug is safer or more effective than another drug when this has not been demonstrated by substantial evidence or substantial clinical experience. Furthermore, promotional materials are misleading if they contain representations that the drug is better or more effective than has been demonstrated by substantial evidence or substantial clinical experience.”

The FDA goes on to list various claims made by Sanofi-Aventis directly comparing docetaxel (Taxotere) with paclitaxel (Taxol). The FDA states that they know of no clinical evidence that supports these claims and asks for substantiation from Sanofi-Aventis. In conclusion, the governmental organization demands that Sanofi-Aventis respond with a full list of all promotional materials for Taxotere and a plan for discontinuing the materials that make the unsubstantiated claim.

Side Effects

One major determining factor that can sway patients who are struggling with decisions about their personal treatment plan is the list of side effects associated with each drug. Even if a drug has a slight clinical advantage in terms of survival, a patient may choose a different treatment if they have a history of severe reactions to toxic medication or if the drug has the potential to exacerbate pre-existing health conditions. Both Taxotere and Taxol can cause anaphylaxis and death in rare cases.

It is therefore of utmost importance that oncology doctors share the full range of side effects that a patient might experience while on the drug or even months or years after. Even uncommon side effects are crucial to decision making so that a patient can come to terms with all the possible consequences of their choice. In turn, pharmaceutical companies are required to disclose all common and uncommon side effects as reported in the clinical trials on the FDA label and in their own published research. New side effects often emerge over time as the long-term effects of these drugs can be observed and evaluated. When this happens, the drug label should be updated to reflect long-term realities.

Taxol Side Effects

One reason why Taxotere was considered a preferred method of treatment for breast cancer over Taxol for some time was the rate of hypersensitivity allergic reactions associated with paclitaxel (Taxol). Early versions of the drug caused more frequent deadly allergic reactions than Taxotere. This allergic reaction can almost always be avoided by taking Abraxane, which is also a brand name version of paclitaxel. Abraxane has been developed to reduce allergic reactions, as it is dissolved in its carrying solution differently. Unfortunately, Abraxane is much more expensive than Taxol or the generic brand of paclitaxel, so insurance companies may not pay for it unless Taxol is tried first and cannot be tolerated. In addition, allergic reactions to Taxol can now be better controlled and monitored with corticosteroids.

In addition, at first, Taxol was administered over a period of three hours every three weeks, like Taxotere. This schedule of administration caused more toxicity in patients and severe side effects such as neutropenia and peripheral neuropathy (low white blood cell count and nerve damage in the hands and feet).

Today, the toxicity of paclitaxel (Taxol) can be mediated through a change in the administration schedule. Many doctors now recommend that paxlitacel (Taxol) in the treatment of breast cancer be administered weekly at weaker doses to spread out the drug and reduce its side effects. Some women, however, see this as a significant disadvantage because they have to visit cancer treatment centers more frequently for their chemotherapy, and they choose to take Taxotere which is administered once every three weeks.

Taxotere Side Effects

Taxotere can also cause allergic hypersensitivity reactions, along with many other side effects that Taxol and Taxotere share. One important side effect associated with Taxotere that is not caused by Taxol, or caused at significantly lower rates, is permanent hair loss. This side effect occurs in anywhere between 3% and 15% of women who complete Taxotere chemotherapy regimens. Although this rate of incidence makes a common side effect, its prevalence was not widely acknowledged or communicated to patients deciding between Taxotere and Taxol for over a decade. This lack of transparency, combined with claims of superiority made by Sanofi-Aventis, Inc., may have caused hundreds of thousands of women to choose Taxotere, believing that it was more effective and equally as safe as the alternative, Taxol.

Not only is the claim that Taxotere is superior in the treatment of breast cancer unsubstantiated, over seven hundred women have now filed lawsuits against Sanofi-Aventis, claiming that the company purposefully withheld data about permanent hair loss and falsely claimed that Taxotere was more effective in fighting breast cancer in order to profit off of the sale of their drug. Although some women may have chosen Taxotere over Taxol, regardless of the possible effects on their appearance, they believe the decision should have been theirs to make and that they had a right to all relevant information about the toxic side effects of a drug which they were paying thousands of dollars to receive. To file your own lawsuit and add your story to the growing movement, call trial attorneys Charles Gilman and Briggs Bedigian today at (800) 529-6162 or contact them online.

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