New Leukemia Drugs Help Those Who Fail Gleevec

Posted by rob on June 15, 2006 under Uncategorized | Be the First to Comment

 New Leukemia Drugs Help Those Who Fail Gleevec

By Amanda Gardner
HealthDay Reporter

WEDNESDAY, June 14 (HealthDay News) — The prognosis picture for people with chronic myelogenous leukemia (CML) has just gotten even rosier.

Two new studies find that two novel molecular therapies show promise in patients who can’t tolerate, or are resistant to, Gleevec.

“Five years ago, the standard of therapy for these patients was transplant. The response was good, but with great cost, and the patients spent the rest of their lives hovering around the hospital,” said Dr. Mark H. Kirschbaum, director of new drug development in the division of hematology and hematopoietic cell transplantation at City of Hope, in Duarte, Calif.

“Now you can treat them with a pill,” he said.

And because the two new drugs — Sprycel (dasatinib) and Tasigna (nilotinib) — work in different ways, they may help an even wider range of patients.

“It’s just a very complementary strategy that would, in my mind, argue for using dasatinib in combination with Gleevec or nilotinib as a way to prevent resistance in the future,” said Dr. Charles L. Sawyers, senior author of the dasatinib trial and an investigator with the Howard Hughes Medical Institute at UCLA’s Jonsson Cancer Center.

Both studies appear in the June 15 issue of the New England Journal of Medicine.

Sprycel could receive U.S. Food and Drug Administration approval in as little as two weeks, Sawyers said. An FDA advisory panel recommended approval earlier this month.

Gleevec’s success means that it is now the drug against which all other CML therapies are ranked. Data presented at the recent annual meeting of the American Society of Clinical Oncologists (ASCO) showed that overall five-year survival for people with CML was 89 percent (95 percent if only deaths related to CML were considered). At the same time, 93 percent of patients taking the drug had still not progressed from the chronic to the acute phase of the illness.

But not all the findings were so positive. While the relapse rate for Gleevec in newly diagnosed patients taking it as front-line therapy is low — about 4 percent per year — patients who started on a different drug before getting Gleevec tend to relapse earlier, the researchers found.

“Gleevec is great, there’s no question,” Sawyers said, but not everyone will benefit indefinitely. “There is a reason to have a second drug, and the second drug [Sprycel] looks good.”

Another expert agreed.

“Gleevec is doing a fantastic job of taking, but there are still some folks who don’t respond or who can’t tolerate the drug,” said Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society. “These drugs begin to fill in these gaps.”

Participants in the phase 1 trial of Sprycel had been diagnosed with CML for an average of about eight years, and had already relapsed while on Gleevec. Some were now in the more advanced acute phase of the disease.

All participants were given 15 milligrams to 240 milligrams of Sprycel a day in four-week treatment cycles once or twice daily. The drug comes in the form of a pill.

Sprycel produced a good response in 37 of 40 patients with chronic-phase disease, and in 31 of 44 patients in the acute phase.

“We’re seeing basically Gleevec-like results,” Sawyers said. The study was funded by grants from the Leukemia and Lymphoma Society and the U.S. National Institutes of Health.

There were some side effects with dasatinib therapy, including panniculitis, an inflammation of the fat under the skin. A research letter in the same issue of the journal detailed panniculitis in two patients taking dasatinib.

For the second study, also a phase 1 trial, 119 patients with Gleevec-resistant CML received nilotinib orally at different doses once or twice daily.

The drug appeared to be active against CML and the safety profile was “relatively favorable,” the researchers found. The study was funded by drug maker Novartis Pharmaceuticals.

According to experts, nilotinib is like a “super-Gleevec,” a variation on the same molecular theme. Sprycel, on the other hand, works in a completely different way.

Between the two of them, many patients who can’t take Gleevec are still being helped.

“The net is getting wider,” Kirschbaum said. “Now we need a Gleevec for everything.”

“This is emblematic of the sort of situation that we’re going to be seeing more and more of as we go forward,” Lichtenfeld added.

More information

For more on CML, head to the Leukemia and Lymphoma Society (www.leukemia-lymphoma.org ).

SOURCES: Charles L. Sawyers, M.D., investigator, Howard Hughes Medical Institute, UCLA’s Jonsson Cancer Center, Los Angeles; Mark H. Kirschbaum, M.D., director, new drug development, hematology malignancies, division of hematology and hematopoietic cell transplantation, City of Hope, Duarte, Calif.; Len Lichtenfeld, M.D., deputy chief medical officer, American Cancer Society, Atlanta; June 15, 2006, New England Journal of Medicine

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Dasatinib treats resistant cases of CML

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Dasatinib treats resistant cases of CML

By University of California – Los Angeles
Jun 15, 2006, 11:29

An experimental therapy that battles drug resistance in Chronic Myeloid Leukemia (CML) has proved “extremely effective” in fighting cancer, giving patients for whom all conventional therapies have failed another option, researchers at UCLA’s Jonsson Cancer Center reported.

The Bristol-Myers Squibb therapy, Sprycel (dasatinib), treats CML that has mutated and becomes resistant to the leukemia pill Gleevec, said Dr. Charles Sawyers, a professor of hematology/oncology, a Jonsson Cancer Center researcher and lead author of the study, published in the June 15, 2006 issue of the peer-reviewed New England Journal of Medicine.

The results are from a Phase I study of Sprycel. The early results were so favorable that several Phase II studies were launched last year and are almost completed. Because these trials have moved so quickly and because more positive results are anticipated, an advisory panel for the U.S. Food & Drug Administration on June 2 recommended that the agency approve the drug, which could happen before the end of the month, Sawyers said. Like Gleevec, Sprycel also is taken in pill form.

Sawyers characterized the Phase I study results as remarkable, saying the first human trial confirmed the pre-clinical laboratory work and scientific discovery done at UCLA’s Jonsson Cancer Center, where the mechanisms and mutations behind Gleevec resistance were uncovered. The Phase I study was done jointly with MD Anderson Cancer Center.

“This shows that if you have a precise molecular understanding of a drug target you can very quickly decipher the reasons for response and failure to therapy and quickly come up with backup treatment strategies,” said Sawyers, a Howard Hughes Medical Institute investigator. “Gleevec remains a spectacular step forward in the field of targeted therapy. However, some patients develop resistance to the drug after several years of therapy. These patients now have another effective option in this drug.”

Drug development often can take decades. However, it has been just five years since Gleevec was approved. In that time, UCLA scientists were able to discover how the CML in some patients mutated and became resistant to Gleevec and test an existing compound on laboratory models and then in patients with great success.

Resistance in CML patients is associated with mutations in the Bcr-Abl gene that interfere with the drug’s mechanism of action. Sprycel blocks 14 of 15 documented CML mutations known to lead to resistance, Sawyers said. It’s about 300 times more potent than Gleevec as well.

Over five years, about 20 percent of patients become resistant to Gleevec, Sawyers said. One of the reasons Sprycel works so well to combat that resistance is that it binds to the mutant proteins in a different way than Gleevec, and it also inhibits several other tyrosine kinases believed to play roles in cancer growth, Sawyers said.

“The main message is that this drug is extremely effective in CML patients who have failed all standard therapy including Gleevec,” Sawyers said. “The basic science findings all panned out. What we predicted based on laboratory studies proved true in human trials. While there was some concern that this drug might be more toxic because it is more potent, we are delighted to find that it is very well tolerated.”

The UCLA Phase I study enrolled 84 patients – 40 with chronic phase CML, 11 with accelerated phase CML, a more serious form of the disease, and 23 whose CML was in blast crisis, the last and most serious phase of CML. Additionally, 10 patients with acute lymphoblastic leukemia (ALL) were enrolled because they tested positive for the Philadelphia chromosome, the genetic abnormality that characterizes most cases of CML and the primary mutation targeted by the drug.

A major cytogenetic response – a substantial reduction in cells containing the Philadelphia chromosome in the bone marrow – was found in 45 percent of chronic phase patients, Sawyers said. In the patients with accelerated and blast phase CML and in patients with ALL, a major cytogenetic response was reported in 43 percent of patients. The responses have lasted for up to two years in some cases and although the study is complete, a number of patients continue to take the drug and are still being monitored.

Sawyers said it’s possible that Gleevec and Sprycel might be used together in patients with CML as a very effective one-two punch to fight cancer and battle drug resistance.

Lakewood resident Kevin Williams, 41, married and a father of two, was diagnosed with CML in June of 2000. He was put on interferon, the standard treatment for CML at that time. The side effects were brutal . Williams felt as if he had a bad flu all the time. He lost weight and was constantly tired. When it became clear that the interferon was not working, Williams’ UCLA oncologist prescribed Gleevec, which had just been approved by the FDA.

After about 10 months on Gleevec, Williams and his oncologists noticed that he was becoming resistant to the drug. His white blood cell count was more difficult to maintain and Williams had to take more and more Gleevec to achieve a stable response. And he was showing no cytogenetic response at all. The mutated cells in his bone marrow that were causing his CML were not decreasing in number. In June 2005, Williams enrolled in a Jonsson Cancer Center study of Sprycel. A bone marrow test in February surprised Williams and his oncologists – there was absolutely no evidence in his marrow of the mutated cells. Williams was 100 percent negative for cancer just nine months after he started taking Sprycel.

“I feel like this drug has given me my life back again,” said Williams, a computer programmer. “I can now do all the things I used to do before. I feel great.”

Williams has returned to his active life, going snow skiing and road racing his motorcycle. He also spends quality time with his wife, Teresa, and his daughter, Kerri, 13, and son, Brian, 7.

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Patients With Treatment-Resistant Leukemia Achieve High Responses to Tasigna(R) (nilotinib) in First Published Clinical Trial Results

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EAST HANOVER, N.J., June 14 /PRNewswire-FirstCall/ — The first-ever published clinical trial data about the investigational drug Tasigna(R) (nilotinib) showed the compound helped more than 90% of patients diagnosed with an unresponsive form of leukemia, a life-threatening disease.

The data were published today in the New England Journal of Medicine.

In less than five months of treatment, 92% of patients with chronic phase Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML) achieved a complete hematologic response with normal white blood cell counts after having shown resistance or intolerance to optimized Gleevec(R) (imatinib mesylate)* tablets therapy.

In more than a third of these patients, the Ph chromosome, the genetic abnormality that characterizes most cases of CML, was undetectable after treatment with Tasigna, as measured by standard laboratory methods. A total of 106 patients with Ph+ CML participated in this study: 33 patients in blast crisis, 56 patients in accelerated phase, and 17 patients in chronic phase. In addition, 13 patients with Ph+ acute lymphoblastic leukemia were included in the study.

Both Tasigna and Gleevec inhibit Bcr-Abl, the definitive cause of Ph+ CML – in effect, shutting down production of the Ph chromosome. Tasigna was specifically designed to be a highly selective inhibitor of Bcr-Abl and its mutations, which can cause resistance to treatment.

“By selectively inhibiting Bcr-Abl and its common mutations, Tasigna produced dramatic positive responses in patients who had limited treatment options,” said Hagop Kantarjian, MD, Professor of Medicine and Internist, Chair, Department of Leukemia, M.D. Anderson Cancer Center. “These extremely encouraging results reinforce the validity of treating this cancer by specifically targeting the one protein known to cause the disease.”

Patients in the most advanced phases of CML also responded to Tasigna therapy. The overall rate of hematologic response (normalization of white blood cell counts) for patients in accelerated phase was 72% and the rate of cytogenetic response (reduction or elimination of the Ph+ chromosome) was 48%. Among patients in blast crisis, the response rates were 39% and 27%, respectively.

The study investigators concluded that Tasigna was generally well tolerated. Common adverse events included myelosuppression, transient indirect hyperbilirubinemia and skin rashes. Additionally, the investigators noted that Tasigna was usually not associated with certain toxicities seen with Gleevec (e.g. fluid retention, superficial edema, weight gain), or with rare cases of pleural and pericardial effusions.

About Tasigna

Discovered in the biomedical research facilities of Novartis, Tasigna (investigational name AMN107) entered Phase I clinical studies just 21 months after it was first synthesized. It is a next generation tyrosine kinase inhibitor in Ph+ CML with a high affinity and specificity to attach itself to Bcr-Abl and to 32 of 33 mutant forms commonly associated with Ph+ CML. The U.S. Food and Drug Administration (FDA) has granted both fast track designation and orphan drug status to Tasigna. Tasigna also received orphan drug status from the European Medicines Agency (EMEA). Novartis is now planning to submit Tasigna for U.S. and EU regulatory approval in late 2006 compared to earlier estimates for submissions in 2007.

As an investigational compound, the safety and efficacy profile of Tasigna has not yet been established. Access to Tasigna is available only through carefully controlled and monitored clinical trials. These trials are designed to better understand the compound’s potential benefits and risks and data will be filed with regulatory authorities such as the U.S. FDA and the European Medicines Agency for regulatory approval.

About Gleevec

Gleevec (imatinib mesylate) tablets are indicated for the treatment of newly diagnosed adult patients with Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML) in chronic phase. Follow-up is limited. Gleevec tablets are also indicated for the treatment of patients with Ph+ CML in blast crisis, in accelerated phase, or in chronic phase after failure of interferon- alpha (IFN-a) therapy.

Important Safety Information(1)

Severe (NCI Grades 3/4) lab abnormalities-including neutropenia (3%-48%), anemia (<1%-42%), thrombocytopenia (<1%-33%), and hepatotoxicity (3%-6%)-and severe adverse experiences (NCI Grades 3/4), including severe fluid retention (eg, pleural effusion, pulmonary edema, and ascites) and superficial edema (1.8%-11%), hemorrhage (1%-19%) and musculoskeletal pain (2%-9%), were reported among Gleevec patients. Severe fluid retention appears to be dose related, was more common in the advanced phase studies (where the dosage was 600mg/day), and is more common in the elderly. Patients should be weighed and monitored regularly for signs and symptoms of edema, which can be serious or life-threatening. There have also been reports, including fatalities, of cardiac tamponade, cerebral edema, increased intracranial pressure, and papilledema and gastrointestinal perforation.

Bullous dermatologic reactions (eg, erythema multiforme and Stevens- Johnson syndrome) have also been reported. In some cases, the reaction recurred upon rechallenge. Several postmarketing cases note a resolution or improvement of bullous reaction following dose reduction with or without supportive care.

Dose adjustments may be necessary due to hepatotoxicity, other nonhematologic adverse events, or hematologic adverse events. Therapy with Gleevec was discontinued for adverse events in 3% to 5% of patients.

Patients with severe hepatic impairment should be treated at a starting dose of 300 mg/day and should be closely monitored.

Gleevec is metabolized by the CYP3A4 isoenzyme and is an inhibitor of CYP3A4, CYP2D6, and CYP2C9. Dosage of Gleevec tablets should increase by at least 50% and clinical response should be carefully monitored in patients receiving Gleevec tablets with a potent CYP3A4 inducer such as rifampin or phenytoin. Examples of commonly used drugs that may significantly interact with Gleevec include acetaminophen, warfarin, erythromycin, and phenytoin. (Please see full prescribing information for other potential drug interactions).

For daily dosing of 800mg and above, dosing should be accomplished using the 400mg tablets to reduce exposure to iron.

Use of Gleevec tablets is contraindicated in patients with hypersensitivity to imatinib or to any other component of Gleevec tablets.

Women of childbearing potential should be advised to avoid becoming pregnant while taking Gleevec tablets.

Because of the potential for serious adverse reactions in nursing infants, women should be advised to avoid breast-feeding while taking Gleevec tablets.

Common Side Effects(1)

The majority adult patients who received Gleevec in clinical studies experienced adverse events at some time. Most adverse events were mild to moderate in severity. The most frequently reported adverse events (all Grades) were superficial edema (58%-74%), nausea (47%-73%), muscle cramps (28%-62%), vomiting (21%-58%), diarrhea (39%-57%), musculoskeletal pain (38%-49%), and rash with related terms (26%-47%).**

Supportive care may help the management of most mild to moderate adverse events so that the prescribed dose can be maintained whenever possible.

Gleevec tablets should be taken with food and a large glass of water to minimize gastrointestinal (GI) irritation. Gleevec tablets should not be taken with grapefruit juice.

The foregoing release contains forward-looking statements that can be identified by terminology such as “promising,” “extremely encouraging results,” “planning,” “will be filed,” or similar expressions, or by express or implied discussions regarding potential future sales of Gleevec, or regarding the long-term impact of a patient’s use of Tasigna or Gleevec. Such forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause actual results with Tasigna and Gleevec to be materially different from any future results, performance or achievements expressed or implied by such statements. There can be no guarantee that Tasigna will be approved for sale in any market. Nor can there be any guarantee regarding potential future sales of Tasigna or Gleevec. Neither can there be any guarantee regarding the long-term impact of a patient’s use of Tasigna or Gleevec. In particular, management’s expectations regarding Tasigna and Gleevec could be affected by, among other things, unexpected clinical trial results, including new clinical data and additional analysis of existing clinical data; unexpected regulatory actions or delays or government regulation generally; the company’s ability to obtain or maintain patent or other proprietary intellectual property protection; competition in general; government, industry, and general public pricing pressures; and other risks and factors referred to in the Company’s current Form 20-F on file with the U.S. Securities and Exchange Commission. Should one or more of these risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those anticipated, believed, estimated or expected. Novartis is providing this information as of this date and does not undertake any obligation to update any forward-looking statements contained in this document as a result of new information, future events or otherwise.

About Novartis

Novartis Pharmaceuticals Corporation researches, develops, manufactures and markets leading innovative prescription drugs used to treat a number of diseases and conditions, including central nervous system disorders, organ transplantation, cardiovascular diseases, dermatological diseases, respiratory disorders, cancer and arthritis. The company’s mission is to improve people’s lives by pioneering novel healthcare solutions.

Located in East Hanover, New Jersey, Novartis Pharmaceuticals Corporation is an affiliate of Novartis AG (NYSE: NVS) – a world leader in pharmaceuticals and consumer health. In 2005, the Group’s businesses achieved sales of USD 32.2 billion and pro forma net income of USD 6.1 billion. The Group invested approximately USD 4.8 billion in R&D. Headquartered in Basel, Switzerland, Novartis Group companies employ approximately 96,000 people and operate in over 140 countries around the world. For further information please consult http://www.novartis.com/.

  (*)  Known as Glivec(R) (imatinib) outside the U.S.

  (**) Numbers indicate the range of percentages in 4 studies among adult
       patients with Ph+ CML in blast crisis, accelerated phase, and chronic
       phase.

  (1)  Gleevec(R) (imatinib mesylate) tablets prescribing information. East
       Hanover, NJ: Novartis Pharmaceuticals Corporation; 2005.

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