Over the last several years, many innovative cancer therapies have been introduced that improve overall outcomes. Many of these new treatments involve immune therapies that boost the body’s own immune system to attack malignant cells. Without question, these types of treatment strategies have greatly enhanced cancer care. But additional advances are needed since many of these interventions are limited due to side effects and costs. Understanding this, researchers have recently tested new approaches that they have labeled drug factory beads. These beads, which provide interleukin-2 treatment, look to be not only effective but safer than other cancer therapy options. And as a result, many are hopeful these strategies may represent the future of cancer care.
When it comes to cancer treatment, challenges often exist that limit effectiveness. On the one hand, many cancer therapies cause toxic side effects because they are given systemically. Likewise, many cancer drugs are seen as foreign by the body, which can trigger an immune system attack against the treatment. In both instances, the impact of the treatments is less, and the chances of eliminating the cancer reduced. But with these new drug factory beads, these challenges could be avoided to a significant degree. By supplying interleukin-2 treatment or other drugs in a more controlled way, the chance of cancer cures increases substantially.
“A major challenge in the field of immunotherapy is to increase tumor inflammation and anti-tumor immunity while avoiding systemic side effects of cytokines and other pro-inflammatory drugs.” – Amir Jazaeri, Professor of Gynecologic Oncology and Reproductive Medicine, MD Anderson
What Exactly Are Drug Factory Beads?
The new cancer treatment approach that researchers recently tried involves the use of drug factory beads. In essence, these beads represent engineered cells designed to produce specific chemicals known to attack cancers. First, researchers isolated retinal pigmented cells, or RPEs, as the key component of the drug factory beads. These cells were chosen because they are safe and because they do not develop into cancer themselves. They are then manipulated to produce interleukin-2 treatment. This chemical, which is a natural immune system protein, is known to attack cancer cells. Thus, once the cells are implanted, they start producing the protein, which then works against the cancer.
In addition to these RPE cells, drug factory beads are also coated with polymer as a means of protection. Because these cells are foreign to the body, there is a chance the immune system will eliminate them quickly. This would naturally undermine the ability of these beads to release their interleukin-2 treatment. The polymer coating thus makes this less likely for a period of time so the drug factories can go to work. In the study, the encapsulation allowed drug factory beads to produce interleukin-2 treatment for up to 30 days. This was more than enough time for a positive cancer treating effect to be seen.
“If you gave the same concentration of the protein through an IV pump, it would be extremely toxic. With the drug factories, the concentration we see elsewhere in the body, away from the tumor site, is actually lower than what patients have to tolerate with IV treatments. The high concentration is only at the tumor site.” – Amanda Nash, Bioengineering PhD Candidate at Rice University
Less Toxicity, Better Effect
The important aspect of these drug factory beads involves more than their protective coating and cellular reengineering. One of the most important factors regarding this new cancer treatment approach pertains its localized effect. The drug factory beads are notably small, being only about the size of a pinhead. As a type of medical implants, they can be placed immediately adjacent to a tumor where they release their chemicals. In the case of the current study, interleukin-2 treatment was produced near ovarian or colorectal cancers. This effectively eliminated all ovarian cancer cells and nearly all colorectal cancer cells in roughly six days.
Being able to implant drug factory beads making interleukin-2 treatment near cancer cells is important. This increases the level of drug effectiveness. But at the same time, it dramatically reduces the potential side effects these drugs might cause. Most cancer drug treatments are given systemically, using the body’s circulation to take the drug to the cancer site. But in the process, many other healthy tissues are exposed to these chemicals as well. This significantly increases the toxic effects of the drugs, which can limit their use. But with these drug factory beads, systemic toxicity can be substantially reduced. Therefore, not only can localized treatment yield better results, but they can be better tolerated as well.
“We found foreign body reactions safely and robustly turned off the flow of cytokine from the capsules within 30 days. We also showed we could safely administer a second course of treatment should it become necessary in the clinic.” – Omid Veiseh, Assistant Professor of Bioengineering, Rice University
Research Results and Future Promises
The current study involving these drug factory beads was conducted at Rice University. Researchers took mice with ovarian and colorectal cancers and treated them with these localized interleukin-2 treatment implants. In every mouse with ovarian cancer, and in seven of the eight with colorectal cancer, the treatment eliminated the malignancies. Likewise, toxic side effects were minimum, and the drug factory beads remained effective for a month. Based on these results, the researchers where highly optimistic about the future potential of these new cancer treatments. As a result, they hope to initiate human trials later this fall.
In the current study, the researchers chose interleukin-2 treatment because of its positive track record in treating cancers. It is well accepted as a treatment for melanoma and renal carcinoma. Similarly, the researchers believe drug factory beads with interleukin-2 might also be effective for pancreatic, liver, and lung tumors. Of course, the RPE cells can be engineered to produce other immune chemicals and proteins for a more targeted approach. If human trials demonstrate the same impressive results, then this strategy will likely become increasingly popular. Tiny cancer-treating implants could soon be one of the preferred ways of treating a variety of cancers in the years to come.