Avastin: Extending the Life for Advanced Cervical Cancer Patients
Most forms of cancer that reach an advanced stage – with or without spreading (metastasis) – are killers. Cervical cancer is no exception. Whereas the survival rate for women diagnosed with stage 1 cervical cancer is 80-90%, with stage IV the survival rate is less than 15%. In fact, currently, most women diagnosed with stage IV or recurring cervical cancer live less than 12 months.
With statistics like these, medical science considers a victory something that substantially prolongs the life of women with stage IV cancer. That’s the position promoted by combining the drug Avastin (bevacizumab) with standard chemotherapy and confirmed in a recent randomized Phase III clinical trial.
Cervical cancer is the second most common form of cancer in women and the fifth most deadly. Its worst attribute is that during the early stages there are often little or no symptoms. That’s why so many cases of cervical cancer are diagnosed at stage III or stage IV – when treatment is difficult and the prognosis isn’t good.
Where early stage cervical cancer is commonly treated with surgery – hysterectomy (removal of the uterus) or radical trachelectomy (removal of the cervix), later stages are treated with radiotherapy or chemotherapy (singly or in combination). With cervical cancer, the duration and dosage of either radio or chemo therapy is high enough to cause significant problems (side effects and loss of strength), so that patients often see slightly improving cancer conditions with rapidly failing general health. Over the last few decades, doctors and researchers have worked with a number of new chemotherapy formulations, the latest being paclitaxel. So far, none of the treatments constitutes a ‘cure’ for late stage cervical cancer, although there is some improvement in the survival rate.
Putting Avastin into the chemotherapy mix for cervical cancer was a natural development of other uses of Avastin. As the drug bevacizumab, a product of Genentech/Roche, it has already proven to be useful in treating colorectal, lung, breast, glioblastoma, kidney and ovarian cancers. The key to the drug as a cancer fighter is its ability to slow the growth of new blood vessels (it’s an angiogenesis inhibitor). As tumors grow, they also need to expand the blood supply – bevacizumab is successful in blocking or slowing the addition of those capillaries and other blood vessels that supply blood to the tumor – thus slowing its growth. The drug is not a ‘cure’ and, in fact, usually does not stop the growth of tumors entirely. However, often in conjunction with standard chemotherapy it acts like an adjuvant (co-treatment). Given its track record with other forms of cancer, researchers hoped it would prove to be effective in helping the treatment of cervical cancer.
The latest clinical trial of Avastin, sponsored by the National Cancer Institute (U.S.), included 452 patients with a median age of 47. All participants were diagnosed with cervical cancer (or its reoccurrence) in the later stages (III or IV). The trial paired Avastin with the two most prominent chemotherapy regimens – cisplatin plus paclitaxel, and topotecan plus paclitaxel. Part of the trial was to compare the results from the two regiments to see if one or the other fared better with Avastin. However, in the end the differences in results were negligible.
On the other hand, Avastin definitely made a beneficial addition to the treatment. Patients who received Avastin along with chemotherapy lived an average of 17 months – compared with a median survival period of 13.3 months for treatment with chemotherapy alone. The additional 3.7 months is not only statistically significant but considered a ‘big deal’ for this kind of cancer.
Doctors pointed out that progress in treating advanced cervical cancer has been very difficult to come by, so that the ability to add several months of life for most patients represents a welcome improvement.
Bevacizumab does add to the side effects of treatment, increasing the chance for hypertension, a low white blood cell count (neutropenia), and the formation of blood clots. (Note these are all blood related effects, which are expected with an angiogenesis drug such as bevacizumab.) Overall, the side effects are considered tolerable within the range of effectiveness – meaning that they generally don’t make conditions worse, compared to the beneficial effects of the drug.
The successful results of a Phase III clinical trial mean that the drug is more or less ready for submission of approval for commercial use by the U.S. Food and Drug Administration. Avastin is already a $6 billion market for Roche Pharmaceutical and the new market for cervical cancer will enhance that position considerably.