The amazing power of an experimental cancer drug
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The amazing power of an experimental cancer drug
Our Review Summary
This nicely written article describes the highs and lows of a patient treated with the “smart” drug Gleevec, used to fight a rare form of fatal leukemia known as CML as well as a rare cancer known as gastrointestinal stromal tumor (GIST) that is caused by a mutation in a gene named kit. The author, a physician and former president of the Dana Farber Cancer Institute, notes that Gleevec was developed to treat metastatic stromal tumors that have spread throughout the body and do not respond to surgical resection, radiation, or more-standard chemotherapies. He briefly summarizes the history of this drug and its place in current cancer treatment. This approach (a "My Perspective" piece written by a physician)—telling the compelling story of a drug and of a difficult cancer through the unfolding case of a single patient—can have its strengths and weaknesses. In this instance, one strength is that readers get a feel for what it might be like to live on the roller-coaster of a terrible disease as new therapies attempt to smooth out the rough ride. Unfortunately, the story lacks important information that would help readers assess the evidence on this therapy, its potential harms, and its cost-effectiveness. According to the best available evidence, the drug is capable of dramatically shrinking (by about 50%) kit-positive GIST in about half of patients who take it, apparently including the type of patient profiled in this piece. Yet we do not learn this when we read the story. Moreover, “smart” drugs that attempt to spare healthy cells as they kill cancer cells have costs—both in side effects and dollars. Though most patients seem to tolerate Gleevec well, the article does not mention recently reported harms of the medication. (See “Harms of Treatment” above.) Nor does it mention its financial costs. As a staff-written article in the previous day’s edition of the Boston Globe explained, “smart” drugs are very expensive ($3000 to $8000 per month for breast and lung cancer drugs, respectively). Indeed, the earlier Globe article cautions that such high costs are an important consideration and could divide cancer patients of the future into “haves” and “have-nots.” But if people didn't read the previous article and only read this, they learned nothing of cost.
Criteria
Not Satisfactory
Though a staff-written article in the previous day’s edition of the Boston Globe explained that “smart” drugs are very expensive ($3000 to $8000 per month for breast and lung cancer drugs, respectively), this article failed to mention cost. The earlier Globe article cautioned that such high costs are an important consideration and could divide cancer patients of the future into “haves” and “have-nots.” (See http://www.boston.com/yourlife/health/diseases/articles/2007/03/12/a_moving_target/?page=1). But if you only saw this story, you didn't learn about costs.
Not Satisfactory
The article does not provide estimates of Gleevec’s absolute or relative benefits. A recent systematic review concluded that about half of patients taking Gleevec who have advanced unresectable and/or metastatic, KIT-positive GIST (like the patient in the Globe story) will experience a dramatic shrinkage of the tumor (at least a 50% reduction), though it is not possible to predict which patients will respond well. (Health Technol Assess. 2005;9:1-142.)
Not Satisfactory
The article explains that Gleevec and other “smart” cancer drugs “destroy cancer cells yet cause minimal damage to normal cells.” Though most patients seem to tolerate the drug well, the article does not mention recently reported harms of the medication. According to a recent systematic review, "all Gleevec-treated patients experienced adverse effects.” (Health Technol Assess. 2005;9:1-142.) The most serious events are tumor hemorrhage in some 5% of patients. Common serious events include gastrointestinal complications (bleeding, obstruction, perforation, or rupture) and low white blood cell counts. Other common side effects include swelling from fluid (edema), nausea, diarrhea, and muscle pain. Some patients taking Gleevec for gastrointestinal stromal tumors or chronic myelogenous leukemia (CML) may also develop low phosphate levels, or hypophosphate, perhaps from accelerated vitamin D metabolism. (N Engl J Med 2006; 354:2006-13) Left untreated, chronic hypophosphate can impair the ability of bone to renew itself, or lead to rickets and osteomalacia (a painful condition characterized by soft bone that easily bends). A case study reported that a patient taking Gleevec developed a blood clot in the pelvis that moved to the lung, a rare but fatal event. (J Exp Clin Cancer Res. 2006;25:607-10.)
Not Satisfactory
The article does not sufficiently explain the nature or quality of the clinical evidence to support the use of Gleevec in patients with GIST. According to a recent systematic review, there are “no randomized trials that have directly compared [Gleevec] with the current standard treatment in patients with advanced GIST.” Moreover, the reviewers added, “There are many uncertainties surrounding [Gleevec] prescription, such as the length of time patients should be on [Gleevec], the dose, drug resistance and the optimum time-point in the disease course at which to give the drug.” (Health Technol Assess. 2005;9:1-142.) As the Globe article implies, it is also unknown how many months or years Gleevec may extend the life of patient.
Satisfactory
There are no obvious elements of disease-mongering. However, few will face the prospect of tumor cells spilling into the abdomen. One recent estimate put the annual incidence of GIST at about 5000-6000 cases per year.
Not Satisfactory
The author of this article is a physician and former president of the Dana Farber Cancer Institute. He states that Dana Farber was the site of a clinical trial with Gleevec. The article does not disclose potential conflicts of interest. Though it mentions researcher-oncologist George Dmitri, it does not cite independent sources.
Satisfactory
Though sketchy, the article summarizes in a half-sentence other treatment options. It does not quantify their risks or benefits.
Satisfactory
A reader could reasonably infer that the drug Gleevec is approved for the treatment of gastrointestinal stromal tumor (GIST) and that the drug is available to patients seeking care from a cancer specialist.
Satisfactory
The story nicely summarizes the history of “smart” drug development–“stretched over many decades.”
Satisfactory
It does not appear that the story relied solely or largely on a news release.
Total Score: 5 of 10 Satisfactory
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