Gene Transfer Therapy Destroys Tumors in Chronic Lymphocytic Leukemia Patients; Holds Promise For Ovarian Cancer

Penn researchers have shown sustained remissions of up to a year among a small group of advanced chronic lymphocytic leukemia (CLL) patients treated with genetically engineered versions of their own T-cells. This genetically-modified “serial killer” T-cell approach could provide a tumor-attack roadmap for the treatment of  ovarian, lung, and pancreatic cancer, as well as myeloma and melanoma.

In a cancer treatment breakthrough 20 years in the making, researchers from the University of Pennsylvania’s Abramson Cancer Center and Perelman School of Medicine have shown sustained remissions of up to a year among a small group of advanced chronic lymphocytic leukemia (CLL) patients treated with genetically engineered versions of their own T-cells.

The protocol involves removing patients’ cells and modifying them in Penn’s vaccine production facility, followed by the infusion of the new cells back into the patient’s body following chemotherapy. This approach also represents a potential tumor-attack roadmap for the treatment of other cancers including those of the lung and ovaries and myeloma and melanoma. The findings, published simultaneously yesterday in the New England Journal of Medicine (NEJM) and Science Translational Medicine, are the first demonstration of the use of gene transfer therapy to create “serial killer” T-cells aimed at cancerous tumors.

Carl June, M.D., Ph.D., Principal Investigator; Director, Translational Research & Professor of Pathology & Laboratory Medicine, Abramson Cancer Center, University of Pennsylvania

David Porter, M.D., Co-Principal Investigator; Director, Blood & Marrow Transplantation & Professor of Medicine, Abramson Cancer Center, University of Pennsylvania

“Within three weeks, the tumors had been blown away, in a way that was much more violent than we ever expected,” said senior author Carl June, M.D., Ph.D., director of Translational Research and a professor of Pathology and Laboratory Medicine in the Abramson Cancer Center, who led the work. “It worked much better than we thought it would.”

The results of the pilot trial of three patients are a stark contrast to existing therapies for CLL. The patients involved in the new study had few treatment options. The only potential curative therapy would have involved a bone marrow transplant, a procedure which requires a lengthy hospitalization and carries at least a 20 percent mortality risk — and even then offers only about a 50 percent chance of a cure, at best.

“Most of what I do is treat patients with no other options, with a very, very risky therapy with the intent to cure them,” says co-principal investigator David Porter, M.D., Professor of Medicine and Director of Blood and Marrow Transplantation. “This approach has the potential to do the same thing, but in a safer manner.”

Secret Ingredients

Dr. June thinks there were several “secret ingredients” that made the difference between the lackluster results that have been seen in previous trials with modified T cells and the remarkable responses seen in the current trial. The details of the new cancer immunotherapy are detailed in Science Translational Medicine.

After removing the patients’ cells, the team reprogrammed them to attack tumor cells by genetically modifying them using a lentivirus vector. The vector encodes an antibody-like protein, called a chimeric antigen receptor (CAR), which is expressed on the surface of the T-cells and designed to bind to a protein called CD19 (Cluster of Differentiation 19).

Once the T-cells start expressing the CAR, they focus all of their killing activity on cells that express CD19, which includes CLL tumor cells and normal B-cells. All of the other cells in the patient that do not express CD19 are ignored by the modified T-cells, which limits side effects typically experienced during standard therapies.

The team engineered a signaling molecule into the part of the CAR that resides inside the cell. When it binds to CD19, initiating the cancer cell death, it also tells the cell to produce cytokines that trigger other T-cells to multiply — building a bigger and bigger army until all of the target cells in the tumor are destroyed.

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Serial Killers

“We saw at least a 1000-fold increase in the number of modified T-cells in each of the patients. Drugs don’t do that,” June says. “In addition to an extensive capacity for self-replication, the infused T-cells are serial killers. On average, each infused T-cell led to the killing of thousands of tumor cells – and overall, destroyed at least two pounds of tumor in each patient.”

The importance of the T-cell self-replication is illustrated in the New England Journal of Medicine paper, which describes the response of one patient, a 64-year old man. Prior to his T-cell treatment, his blood and marrow were replete with tumor cells. For the first two weeks after treatment, nothing seemed to change. Then on day 14, the patient began experiencing chills, nausea, and increasing fever, among other symptoms. Tests during that time showed an enormous increase in the number of T-cells in his blood that led to tumor lysis syndrome, which occurs when a large number of cancer cells die all at once.

By day 28, the patient had recovered from the tumor lysis syndrome –– and his blood and marrow showed no evidence of leukemia.

“This massive killing of tumor is a direct proof of principle of the concept,” Porter says.

The Penn team pioneered the use of the HIV-derived vector in a clinical trial in 2003 in which they treated HIV patients with an antisense version of the virus. That trial demonstrated the safety of the lentiviral vector used in the present work.

The cell culture methods used in this trial reawaken T-cells that have been suppressed by the leukemia and stimulate the generation of so-called “memory” T-cells, which the team hopes will provide ongoing protection against recurrence. Although long-term viability of the treatment is unknown, the doctors have found evidence that months after infusion, the new cells had multiplied and were capable of continuing their “seek-and-destroy” mission against cancerous cells throughout the patients’ bodies.

Moving forward, the team plans to test the same CD19 CAR construct in patients with other types of CD19-positive tumors, including non-Hodgkin’s lymphoma and acute lymphocytic leukemia. They also plan to study the approach in pediatric leukemia patients who have failed standard therapy. Additionally, the team has engineered a CAR vector that binds to mesothelin, a protein expressed on the surface of mesothelioma cancer cells, as well as on ovarian and pancreatic cancer cells.

In addition to June and Porter, co-authors on the NEJM paper include Bruce Levine, Ph.D., Michael Kalos, Ph.D., and Adam Bagg MB, BCh, all from Penn Medicine. Michael Kalos and Bruce Levine are co-first authors on the Science Translational Medicine paper. Other co-authors include Carl June, M.D., Ph.D., David Porter, M.D., Sharyn Katz, M.D., MTR, and Adam Bagg MB, BCh, from Penn Medicine, and Stephan Grupp, M.D., Ph.D., from the Children’s Hospital of Philadelphia.

The work was supported by the Alliance for Cancer Gene Therapy, a foundation started by Penn graduates Barbara and Edward Netter, to promote gene therapy research to treat cancer, and the Leukemia & Lymphoma Society.

Accompanying NEJM Editorial

In an accompanying NEJM editorial, Walter J. Urba, M.D., Ph.D. and Dan L. Longo, M.D. raise several important consideration in regard to the genetically-modified, serial killer T-cell therapy discussed above.

First, the editorial authors note that chimeric antigen receptors (or CARS) have theoretical advantages over other T-cell–based therapies, including: (i) use of the patient’s own cells, which avoids the risk of graft-versus-host disease; (ii) the ability to create CARs quickly; and (iii) use of the same CAR for multiple patients.

While noting the remarkable clinical outcome of the 64-year old male CLL patient described above, the editorial authors note that in addition to tumor lysis syndrome, the patient experienced B-cell depletion and hypogammaglobulinemia. Although these conditions may not create a major problem in patients with CLL, the authors state that the persistence of activated T-cells, memory T-cells, or both could pose substantial problems in other tumor types.

According to the editorial authors, both toxic effects to the target organ and also “on-target, but off-organ” toxic effects have been observed by other researchers in the past because of unanticipated cross-reactive target antigens.

While toxicity may become more of a problem as more potent second- and third-generation CARs are used in patients with different tumor types, the authors explain that additional safety measure may help offset that risk. The safety measures highlighted in the editorial include: (i) the infusion of a lower number of T-cells, (ii) the use of immunosuppressive agents, and (iii) the introduction of an inducible “suicide signal” to kill the cells when they are creating mischief.

In connection with the third safety measured provided above, the authors state that a novel, non-immunogenic, inducible caspase 9suicide gene” has already been developed. Nevertheless, the authors warn that the suicide gene strategy may not have time to work properly because the deaths from toxic effects reported in the past have been severe and occurred within hours after administration of the gene-transfected cells.

The editorial authors conclude that only with the more widespread clinical use of CAR T-cells will researchers learn whether the results reported by Porter et al. represent a true advancement toward a clinically applicable and effective therapy, or alternatively, another promising strategy that runs into an insurmountable barrier which is difficult to overcome.

About Penn Medicine

Penn Medicine is one of the world’s leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation’s first medical school) and the University of Pennsylvania Health System, which together form a $4 billion enterprise.

About the University of Pennsylvania Perelman School of Medicine

Penn’s Perelman School of Medicine is currently ranked #2 in U.S. News & World Report’s survey of research-oriented medical schools and among the top 10 schools for primary care. The school is consistently among the nation’s top recipients of funding from the National Institutes of Health, with $507.6 million awarded in the 2010 fiscal year.

About the University of Pennsylvania Health System

The University of Pennsylvania Health System’s patient care facilities include: The Hospital of the University of Pennsylvania — recognized as one of the nation’s top 10 hospitals by U.S. News & World Report; Penn Presbyterian Medical Center; and Pennsylvania Hospital – the nation’s first hospital, founded in 1751. Penn Medicine also includes additional patient care facilities and services throughout the Philadelphia region.

Penn Medicine is committed to improving lives and health through a variety of community-based programs and activities. In fiscal year 2010, Penn Medicine provided $788 million to benefit our community.

Sources:

  • Urba WJ & Longo DL. Redirecting T CellsN Engl J Med Editorial. Published online August 10, 2011 (10.1056/NEJMe1106965).

OU’s Non-Toxic Drug Makes Ovarian Cancer Cells Respond To New Treatment & Undergo Cell Suicide

“Cancer researchers at the University of Oklahoma Health Sciences Center have found a way to turn ineffective new cancer drugs into cancer-fighters. By using their patented chemical compound, SHetA2, researchers tricked cancer cells into responding to new treatments and undergoing cell suicide. … [T]he compound will work with several cancers, including lung, kidney, ovarian, colon and pancreatic cancer. … [The] research team … patented the SHetA2 Flex-Het and hope[s] to start clinical trials for the compound within a year. …

Cancer researchers at the University of Oklahoma Health Sciences Center have found a way to turn ineffective new cancer drugs into cancer-fighters. By using their patented chemical compound, SHetA2, researchers tricked cancer cells into responding to new treatments and undergoing cell suicide. The research appears in the journal Gynecologic Oncology.

Doris Mangiaracina Benbrook, Ph.D., is in her lab at the University of Oklahoma Health Sciences Center in Oklahoma City. (Photo: Univ. of Oklahoma Health Sciences Center)

“This discovery means that we can use our non-toxic cancer prevention pill to improve treatment for people who already have cancer,” said Doris Mangiaracina Benbrook, Ph.D., principal investigator on the project. “All studies to date have not found any side effects of taking our drug, giving hope that we can prevent cancer in healthy people, and improve treatment for cancer patients, without increasing toxicity.”

The latest study looked at an upcoming class of cancer treatment drugs that worked well in experimental models, but proved ineffective against many human tumors. Dr. Benbrook and her team decided to test their compound’s ability to “fix” the problem. It worked.

“The new chemotherapy drugs are antibodies that bind to cell surface receptors called ‘Death Receptors.’ The binding of the antibodies activates the death receptors in cancer cells and causes cell suicide with little harm to normal cells. Many cancers, however, are resistant to the antibodies,” Benbrook said. “We’ve shown that SHetA2 treatment can make ovarian and kidney cancer cells sensitive to the death receptor antibodies and kill the cancer.”

Benbrook said the compound will work with several cancers, including lung, kidney, ovarian, colon and pancreatic cancer.

“It would be a significant advancement in health care if we could avoid the severe toxicity and suffering that late stage cancer patients have to experience,” Benbrook said.

The synthetic compound, SHetA2, a Flex-Het drug, was created by Benbrook with the help of chemist Darrell Berlin at Oklahoma State University. The compound directly targets abnormalities in cancer cell components without damaging normal cells. The disruption causes cancer cells to die and keeps tumors from forming.

Flex-Hets or flexible heteroarotinoids are synthetic compounds that can change certain parts of a cell and affect its growth. Benbrook and her research team have patented the SHetA2 Flex-Het and hope to start clinical trials for the compound within a year. If the compound continues to be found safe, it would be developed into a pill to be taken daily like a multi-vitamin to prevent cancer. This new discovery means that the pill also could be used to make patients, who already have cancer, better respond to treatment.

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Sources:

PhRMA Report Shows Record Number of Development Drugs to Treat Cancer; 63 Ovarian Cancer & 203 Solid Tumor Drugs Listed

“Responding to President Obama’s call for ‘a cure for cancer in our time,’ the Pharmaceutical Research and Manufacturers of America (PhRMA) delivered a new report today on medicines in the research pipeline for cancer. The report shows that America’s pharmaceutical research and biotechnology companies are testing a record 861 new cancer medicines and vaccines. The medicines listed in the report are being tested in human clinical trials or are awaiting approval by the U.S. Food and Drug Administration. [Libby’s H*O*P*E*™ : 63 Ovarian Cancer Drugs & 203 Solid Tumor Drugs are listed in the 2009 PhRMA report (pp. 51 – 55)]. …”

“New Report Shows Record Number of Medicines In Development to Treat Leading Causes of Cancer

phrmalogoDenver, CO (April 1, 2009) – Responding to President Obama’s call for ‘a cure for cancer in our time,’ the Pharmaceutical Research and Manufacturers of America (PhRMA) delivered a new report today on medicines in the research pipeline for cancer. The report shows that America’s pharmaceutical research and biotechnology companies are testing a record 861 new cancer medicines and vaccines. The medicines listed in the report are being tested in human clinical trials or are awaiting approval by the U.S. Food and Drug Administration. [Libby’s H*O*P*E*™ Note: 63 Ovarian Cancer Drugs & 203 Solid Tumor Drugs are listed in the 2009 PhRMA report (pp. 51-55)].

Nationwide, cancer is the second leading cause of death, affecting more than 10 million Americans, according to the National Cancer Institute. This year, more than half a million Americans are expected to die of cancer-more than 1,500 a day. In Colorado, the lifetime risk of cancer is 1 in 2 for males and 2 in 5 for females. The most commonly diagnosed cancer in the state is breast cancer, followed by prostate and lung cancer.

‘We released this report in Denver because of Colorado’s growing role in developing cancer medicines,’ said PhRMA Senior Vice President Ken Johnson, who unveiled the report at the State Capitol Building.

‘Oncology is one of Colorado’s core research competencies, so the President’s call to cure cancer resonates powerfully in our state,’ said Colorado Lt. Governor Barbara O’Brien. ‘We are proud that the cancer medicines now in the research pipeline in Colorado are contributing substantially to the incredible progress made in the last five years by biopharmaceutical companies in developing new and more effective cancer treatments. The nation must continue its strong commitment to the cutting-edge pharmaceutical research that will enable cancer patients to live longer, healthier, and more productive lives.’

billytauzin

Billy Tauzin, President and Chief Executive Officer, The Pharmaceutical Research and Manufacturers of America (PhRMA). PhRMA's mission is to conduct effective advocacy for public policies that encourage discovery of important new medicines for patients by pharmaceutical & biotechnology research companies.

‘I am one of those patients who was diagnosed with cancer and was given a new treatment that brought me from the brink of death back to life,’ says PhRMA President and CEO Billy Tauzin. ‘The men and women working for America’s pharmaceutical research companies are committed to developing new cancer medicines that, one day, could eradicate cancer all together.’

Cancer medicines being developed include 122 for lung cancer, the leading cause of cancer death in the United States; 107 for breast cancer, which is expected to strike more than 180,000 American women this year; 70 for colorectal cancer, which is the third most common cancer in both men and women; and 103 for prostate cancer, which this year is expected to kill 28,000 American men. Additional medicines target brain cancer, kidney cancer, ovarian cancer, pancreatic cancer, skin cancer, and others.

The medicines represent many cutting-edge approaches, including a drug that delivers a synthetic version of a substance derived from scorpions directly to brain tumor cells; a number of cancer vaccines; medicines that target and kill specific cancer cells; and treatments that activate the patient’s general immune system to destroy cancer.

‘Researchers are making exciting progress in the search for new cures and treatments for cancer. But these efforts are wasted if the medicines we develop aren’t accessible to patients who need them,’ said Johnson.

Help is available to patients in need through the Partnership for Prescription Assistance (PPA), a program sponsored by America’s pharmaceutical research companies. To date, the PPA has helped more than 5.7 million patients nationwide, including more than 72,000 people in Colorado. Since its launch in April 2005, the PPA bus tour has visited all 50 states and more than 2,500 cities to educate people about patient assistance programs.

The “Help is Here Express” is staffed by trained specialists able to quickly help uninsured and financially struggling patients access information on more than 475 patient assistance programs, including nearly 200 programs offered by pharmaceutical companies. When the “Help is Here Express” moves on, patients can visit PPA’s easy-to-use Web site (www.pparx.org) or call the toll-free phone number (1-888-4PPA-NOW).

Click here to read Medicines in Development for Cancer 2009. [Adobe Reader PDF Doc.]

Read the backgrounder fact sheet here.

______________________________________________________

Pharmaceutical Research & Manufacturers of America

The Pharmaceutical Research and Manufacturers of America (PhRMA) represents the country’s leading pharmaceutical research and biotechnology companies, which are devoted to inventing medicines that allow patients to live longer, healthier, and more productive lives. PhRMA companies are leading the way in the search for new cures. PhRMA members alone invested an estimated $50.3 billion in 2008 in discovering and developing new medicines. Industry-wide research and investment reached a record $65.2 billion in 2008.

PhRMA Internet Address: www.phrma.org

For information on stories of hope and survival, visit: http://sharingmiracles.com/

PhRMA en Español: www.nuestraphrma.org

For information on how innovative medicines save lives, visit: www.innovation.org

For information on the Partnership for Prescription Assistance, visit: www.pparx.org

For information on the danger of imported drugs, visit: www.buysafedrugs.info”

SourceNew Report Shows Record Number of Medicines In Development to Treat Leading Causes of Cancer, Press Release, Pharmaceutical Research and Manufacturers of America, April 1, 2009.