Sunitinib brings Adult Acute Lymphoblastic Leukemia (ALL) to Remission – RNA Sequencing – FLT3 Receptor Blockade
Curator: Aviva Lev-Ari, PhD, RN
Pazopanib versus Sunitinib in Renal Cancer
To the Editor:
Cancer treatments are expensive. The estimation of the total cost can be challenging because of several factors such as efficacy, toxicity, and the costs and duration of supportive care and end-of-life care. Motzer et al. (Aug. 22 issue)1 report similar efficacy but a favorable safety and quality-of-life profile and less medical resource utilization with pazopanib as compared with sunitinib in first-line therapy for metastatic renal cancer. Since oncology is becoming an increasingly value-based specialty, we wanted to highlight another important aspect of this trial. Pazopanib appears to be favorable not only in terms of safety and quality of life, but also in terms of overall cost. A 30-day supply of pazopanib (at a dose of 800 mg daily) ranges from $3,500 to $8,556, whereas a 30-day supply of sunitinib (at a dose of 50 mg daily) ranges from $4,500 to $13,559.2 The total cost of pazopanib during the median progression-free survival of 8.4 months is $29,400 to $71,870, and the total cost of sunitinib during the median progression-free survival of 9.5 months is $42,750 to $127,454. Less toxicity and less medical resource utilization with pazopanib will most likely further lower the overall costs of treatment with this agent. Comparative-effectiveness trials hold great promise for maximizing patient safety, improving treatment outcomes, and reducing costs.
Ryan Ramaekers, M.D.
Mark Tharnish, Pharm.D.
M. Sitki Copur, M.D.
Saint Francis Cancer Treatment Center, Grand Island, NE
No potential conflict of interest relevant to this letter was reported.
To the Editor:
Motzer et al. report a combined analysis of two open-label noninferiority trials (927 patients in the original trial and 183 patients in a second trial), each of which compared pazopanib with sunitinib with respect to progression-free survival in renal-cell carcinoma. Quality-of-life outcomes were subjective.
Analysis of noninferiority trials is notoriously difficult.1,2 The authors’ analysis of the trials, which was open-label because of the different administration schedules of the drugs, presents problems in interpreting progression-free survival and quality of life. The studies define disease progression differently. The larger study defined progression-free survival according to independent review. The protocol for the smaller study states that progression-free survival “will be summarized . . . based on the investigator assessment.” Inference from subjective outcomes in unmasked trials (e.g., quality of life in both studies and progression-free survival in the smaller study and therefore in the combined analysis) is subject to well-known bias. Moreover, the article does not state how many of the 379 participants (34%) who discontinued the intervention before death or disease progression (see Fig. S2 in the Supplementary Appendix, available with the full text of the article at NEJM.org) were assessed for progression-free survival. A fair comparison must use rigorous methods to handle missing data.3 Since the article did not deal appropriately with missing data, its conclusions regarding noninferiority are uninterpretable.
Janet Wittes, Ph.D.
Statistics Collaborative, Washington, DC
Dr. Wittes reports that her company, Statistics Collaborative, has consulting agreements with both GlaxoSmithKline and Pfizer, the manufacturers of the drugs discussed in the article by Motzer et al. In addition, Statistics Collaborative has contracts with several other companies that produce drugs for patients with cancer. No other potential conflict of interest relevant to this letter was reported.
To the Editor:
Motzer et al. state that “the results of the progression-free survival analysis in the per-protocol population were consistent with the results of the primary analysis.” However, the predefined margin of noninferiority (<1.25) was not met. The upper limit of the confidence interval (1.255) was clearly above the defined threshold.1 In a noninferiority trial, the use of the intention-to-treat population is generally nonconservative,2 the full analysis set and the per-protocol analysis set are considered to have equal importance, and the use of the intention-to-treat population should lead to similar conclusions for a robust interpretation.3 Thus, it is surprising that the authors did not come to or discuss the same conclusions as that of the French National Authority for Health4: “serious doubt exists about the noninferiority result of pazopanib compared to sunitinib” and “the clinical significance of the noninferiority threshold defined in the protocol was an efficacy loss of 2.2 months in the median progression-free survival. This is too large for patients.”
Jochen Casper, M.D.
Silke Schumann-Binarsch, M.D.
Claus-Henning Köhne, M.D.
Klinikum Oldenburg, Oldenburg, Germany
Dr. Casper reports receiving consulting fees from Bayer, Novartis, and Pfizer and speaking fees from Novartis and Pfizer. No other potential conflict of interest relevant to this letter was reported.
The authors reply: In reply to Ramaekers et al.: we agree that decisions regarding the provision of health care include economic evaluations to identify treatments that provide the best clinical benefit at an acceptable cost.
To clarify a point in the letter by Wittes: the primary end point of this phase 3 trial was progression-free survival evaluated by an independent review committee; these data were assessed for all 1110 patients from both trials. This is specified in the protocol. The consistency of the quality-of-life results with the observed differences in the safety profiles for the two drugs speaks to the absence of bias in the quality-of-life outcome. The number of patients in whom follow-up ended before progression was assessed by the independent review committee was balanced between the two groups: 156 patients in the pazopanib group (28%) and 168 patients in the sunitinib group (30%). To Wittes’s final point regarding rigorous methods to handle missing data: the algorithm for assigning disease-progression and censoring dates followed the Guidance for Industry of the Food and Drug Administration1 and is included in the protocol of our article.
In reply to Casper et al.: there is no consensus regarding whether the per-protocol population is more conservative than the intention-to-treat population for the noninferiority analysis.2,3Reviews of noninferiority trials indicate that the per-protocol population is not generally more conservative than the intention-to-treat population, and there are scenarios in which the per-protocol analysis itself could introduce bias.3 A systematic review indicated that more than 70% of published findings from noninferiority trials in oncology show results in only the intention-to-treat population and not in the per-protocol population.4 Our phase 3 trial had a single primary analysis in the intention-to-treat population, with the per-protocol population included as a key sensitivity analysis, as supported by Fleming et al.5 No formal hypothesis testing was planned for the per-protocol population, nor was the trial powered for this. Consistency of the point estimates was desired to show an absence of bias due to the analysis population. This absence of bias was shown by the consistency of the hazard ratios (1.07 in the per-protocol analysis vs. 1.05 in the primary analysis). For an underpowered per-protocol comparison, it is inappropriate for Casper et al. to interpret that the upper bound that barely exceeded 1.25 in our per-protocol analysis is an indication of inconsistency of results across the two populations. The noninferiority margin was selected in consultation with oncology experts, and justification of the margin is in the protocol.
Robert J. Motzer, M.D.
Memorial Sloan-Kettering Cancer Center, New York, NY
Lauren McCann, Ph.D.
Keith Deen, M.S.
GlaxoSmithKline, Collegeville, PA
Since publication of their article, the authors report no further potential conflict of interest.
REFERENCESFood and Drug Administration. Guidance for industry: clinical trial endpoints for the approval of cancer drugs and biologics. May 2007 (http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/ucm071590.pdf).Jones B, Jarvis P, Lewis JA, Ebbutt AF. Trials to assess equivalence: the importance of rigorous methods. BMJ 1996;313:36-39[Erratum, BMJ 1996;313:550.]
CrossRef | Web of Science | MedlineBrittain E, Lin D. A comparison of intent-to-treat and per-protocol results in antibiotic non-inferiority trials. Stat Med 2005;24:1-10
CrossRef | Web of Science | MedlineTanaka S, Kinjo Y, Kataoka Y, Yoshimura K, Termukai S. Statistical issues and recommendations for noninferiority trials in oncology: a systematic review. Clin Cancer Res 2012;18:1837-1847
CrossRef | Web of Science | MedlineFleming TR, Odem-Davis K, Rothmann MD, Li Shen Y. Some essential considerations in the design and conduct of non-inferiority trials. Clin Trials2011;8:432-439
CrossRef | Web of Science | MedlineSOURCE
Original Article Published on 7/9/2012
On the lower left corner of this page – Watch the VIDEO
Dr. Lukas Wartman, is a Cancer Researcher specializing in Leukemia. He suspected he had Leukemia, the very disease he had devoted his medical career to studying.
After years of treatment and two relapses of ALL, he has exhaused all conventional approaches to his disease. At Washington University in St. Louis, his colleagues in the lab, decoded Dr. Wartman’s genetic information by genome sequencing techniques t determine the genetic cause of his ALL. The team found an overactive gne, FLT3 on Chromosome 13. The gene was treated with pfizer’s Suntinib drug for advanced kidney cancer.
Blood samples free of ALL found in days after using the drug. As results were very promising, Pfizer, the drug’s maker who has turned down Dr. Wartman’s request for the drug under their compassionate use program, though he explained that his entire salary was only enough to pay for 7 1/2 months of Sutent (Suntinib). While he does not know why Pfizer gave him the drug finally, he suspects it was the plea of his Nurse Practitioner, Stephanie Bauer, NP.
Identification of the genetic cause for his ALL, thus discovering a breakthough in understanding and treatment for ALL in other patients, involved the following steps:
two tissue samples taken from Dr. Wartman’s Bone marrow and skin cells
Extracts of DNA and RNA from Dr. Wartman’s cells, two types of genetic material tested
DNA sequesnces showed genetic mutations possibly related to his ALL, none seemed treatable. However, RNA sequencing revealed that a normal Gene, FLT3, on cheomozome 13, was overactive in his leukemia cells
The FLT3 gene helps create new white blod cells in the bone marrow. Dr. Wartman’s marrow bone cells were covered with an extreme number of FLT3 receptors which possibly caused the growth of his leukemia.
TREATMENT – Receptor Blockade
Drug known to block FLT3 receptor, Sunitinib, used for kedney cancer treatment, was given to Dr. Wartman. Two weeks after Dr, Wartman began taking the drug, tests revealed that his leukenia was in remission.
Pfizer has NOW a NEW market for Sunitinib — All CANCER PATIENTS DIAGNOSED WITH Adult acute lymphoblastic leukemia (ALL) where an overactive FLT3 gene on chomosome 13 is found.
NEW TREATMENT OPTIONS FOR Adult acute lymphoblastic leukemia (ALL)
Thus, any (ALL) diagnosed patient needs to be tested for Chromosome 13, ONLY rather then the entire genome sequencing of the Patient. If FLT3 is not found overactive, THEN proceed with entire genome sequencing of the Patient. IF another gene is overactive FIND DRUG FOR RECEPTOR BLOCKADE.
SIZING THE MARKET FOR FLT3 BLOCKADE DRUGS: KIDNEY CANCER vs LEUKEMIA
The Market for Adult ALL is much bigger than the market for kidney cancer. Thus, this discovery regarding the remission of Dr. Wartman’s remission following two relapses is so significant for Pfizer and for any patient with the diagnosis of Adult ALL.
I recommend the reader to click on the links and follow the reactions of the public to this article in The New York Times.
Read HUNDREDS of Comments by Cancer Patients and the readers of The New York Times Health Section