CAR Immune Cells to Treat Childhood Cancers


In clinical trials, cancer treatments that use genetically modified versions of a patient’s own cells to specifically target the disease have remarkable results. The next step for these companies that spent enormous amounts of time, capital, and intellectual energy inventing and designing these treatments is to get them into hospitals despite their enormous price tags.

Novartic CAR T-Cell therapy

In two separate clinical trials, one sponsored by the Swiss company Novalis AG and another by the Seattle-based biotech company Juno Therapeutics Inc., close to 90% of all patients saw their leukemia completely disappear after being given experimental “CAR” or “chimeric antigen receptor” T-cell therapies.

Both trials examined small numbers of patients (22 children in the Novartis trial and 16 adults in the Juno trial). These patients had acute lymphoblastic leukemia, which is the most common childhood cancer. All of them had also not responded to the available standard treatments. Consequently, both companies are now conducting larger trials.

“CAR T cells are probably one of the most exciting concepts and fields to come out in cancer in a very, very long time,” says Dr. Daniel DeAngelo, a Boston-based hematologist and associate professor of medicine at Harvard Medical School, who wasn’t involved in either study.

Usman Azam, head of cell and gene therapies at Novartis, calls the therapies “critically important” for Novartis. “I think that a cure for cancers such as leukemia and lymphoma through a CAR technology is plausible,” said Dr. Azam in an interview with The Wall Street Journal. “Our job is to get this into patients as soon as we feasibly can.”

Novatis created a new research unit headed by Dr. Azam. Novartis’ rationale is to accelerate the advent of CAR T-Cell Therapy to medical markets. The U.S. Food and Drug Administration (US FDA) granted Novartis’ leading CAR therapy “breakthrough” designation in July of 2014. Presently Novartis wants to file it with regulators in 2016.

CAR therapies use the patient’s own immune system to fight the cancer, but with a genetic-engineering twist. “Immunotherapies,” culture immune cells from the patient and manipulate them in culture to sensitize them to the cancer. CAR therapies extract T-cells, which are disease-fighting white blood cells, from a patient’s blood. These T-cells are then genetically engineered and grown in a laboratory for around 10 days and reintroduced into the patient.

The T-cells are usually infected with a hamstrung virus that can introduce genes into cells but cannot productively infect them. These recombinant viruses endows the T-cells with genes that encode chimeric antigen receptors, or CARs. CARS bind specifically to proteins on the surface of malignant cancer cells. Once attached to the cancer cells, the T-cells can kill them very effectively.

Both Novartis and Juno are tapping academic scientists to develop their treatments. For example, Novartis has teamed with the University of Pennsylvania and Juno has formed a formal relationships with scientists at Memorial Sloan-Kettering Cancer Center in New York, Seattle Children’s Hospital and the Fred Hutchinson Cancer Research Center, which is also in Seattle.

Even though Novartis and Juno will probably be the first to bring their immunotherapies to the market, other companies are also in the hunt to bring similar therapies to medical markets. Pfizer Inc., Kite Pharma Inc., and Celgene Corp., which is working in collaboration with Bluebird Bio Inc. all are developing competing strategies.

“Competition will keep all of the companies involved on their toes,” said Hans Bishop, Juno’s chief executive.

Unfortunately, CAR therapies still have a few unanswered questions surrounding them. For example: “How long do they last?” Given the small numbers of patients who have been treated with these treatments to date, it is very hard to tell with the available data. Another confounding factor is that those patients in the previous clinical trials whose cancer went into remission after the CAR therapies then became eligible for stem-cell transplants, which can also prolong survival.

Secondly, a potentially dangerous side effect called “cytokine-release syndrome,” shows the therapy is working, but can cause a sharp drop in blood pressure and a surge in the heart rate. The deaths of two patients in a Juno-backed Sloan-Kettering trial in March caused a temporary halt in the study because of worries over these particular adverse reactions.  “Patients need to be healthy enough to combat that side effect,” says Mr. Bishop, who thinks it is now manageable. Patients are once again being recruited for this trial, and patients with a risk of heart failure are excluded, and the modified cell dose for patients with very advanced leukemia also has been lowered.

But largest hurdle of all will probably be the cost of these therapies. Since they are a genetically engineered product, CAR T-cells are very complex to manufacture; each batch is composed of unique, personalized T-cells that were made from a patient’s own blood cells. The inability to mass-produce CAR T-cells will definitely increase the price companies charge for them.

“What we’re talking about here is a single, very expensive therapy that’s used once for a specific patient and is not generalizable,” says Dr. Malcolm Brenner, director of the Center for Cell and Gene Therapy at the Texas Children’s Hospital in Houston, who, in MArch, signed an agreement to commercialize his own CAR research with Celgene.

Novartis and Juno both insist that it is too early to speculate on the price of the treatment, but Dr. Usman agrees the challenge is getting the manufacturing process to “a viable level where it’s both affordable and attractive.”

Citigroup believes CAR therapies could cost in excess of $500,000 per patient, which it notes is roughly in line with the cost of a stem cell transplant, even though most analysts think it is too early to estimate potential revenue or price.

“This technology needs to be widely developed and accessible to patients,” says Dr. DeAngelo. “If the cost is going to be a hindrance, it’s going to be a really sad day.”

Scalability and cost are one reason Pfizer is taking a different approach to this field. “We would like to take it to the next level, where CAR therapies become a more standardized, highly controlled treatment,” said Mikael Dolsten, Pfizer’s head of global research and development.

Working with French biotech Cellectis SA, Pfizer wants to develop a generic CAR therapy for use in any patient. While this will certainly lower the cost of the treatment, since it is the result of a mass-produced, off-the-shelf-product, this work is still at the preclinical stages and may not work in humans.

Global head of health-care research at Société Générale, Stephen McGarry, thinks that the revolutionary treatments being developed by Novartis and Juno could justify “astronomical” prices, he believes health-care payers and patients will probably protest such high prices. “When you look at the initial data with the Novartis therapy, you’re getting cures in some kids—what do you charge for that?” he asks.

Advertisements

Published by

mburatov

Professor of Biochemistry at Spring Arbor University (SAU) in Spring Arbor, MI. Have been at SAU since 1999. Author of The Stem Cell Epistles. Before that I was a postdoctoral research fellow at the University of Pennsylvania in Philadelphia, PA (1997-1999), and Sussex University, Falmer, UK (1994-1997). I studied Cell and Developmental Biology at UC Irvine (PhD 1994), and Microbiology at UC Davis (MA 1986, BS 1984).