Key Points
- ATX-101 stopped tumor growth in 70% of terminally-ill cancer patients with multiple types of treatment-resistant cancers, including colorectal and lung cancers.
- ATX-101 sensitizes tumors to cell death, increasing chemotherapeutic effectiveness so that lower chemotherapy doses are needed.
- ATX-101 suppresses the protein Proliferating Cell Nuclear Antigen (PCNA) that allows cancer cells to survive despite being under a high degree of cellular stress.
There are at least 200 different types of cancer, and unique treatment regimens have been devised to target each one of them. As such, finding one treatment for multiple cancers would be an unprecedented healthcare feat.
Published in Oncogene, Millward and colleagues from the University of Western Australia have designed and produced a new drug, ATX-101, that targets a molecular vulnerability shared by all types of cancer, the PCNA protein. In a small clinical trial, they found that ATX-101 treatment stopped tumor growth in 14 of 20 (70%) terminally-ill patients with treatment-resistant cancer. What’s more, the ATX-101-responsive patients had been diagnosed with cancers ranging from colorectal to lung cancer, suggesting that the drug can treat multiple cancer types. The study’s findings could mean that by targeting PCNA, ATX-101 can stop tumor progression for multiple cancer types.
ATX-101 Targets Cancer Cells While Leaving Healthy Cells Unharmed
“Cancer cells are more stressed than other cells. However, they don’t die but continue to grow even when they are damaged,” said Marit Otterlei, one of the study’s key contributing authors, in a press release. “Conventional cancer treatment with chemotherapy puts more stress on the cancer cells so that the cells eventually do die. Chemotherapy affects all cells, including the normal ones, such as in the hair follicles, and thus affects the whole body with many side effects like hair loss.”
Interestingly, ATX-101 blocks the activation of the protein PCNA that helps cancer cells survive high stress levels. In doing so, ATX-101 not only helps stop tumor growth but can sensitize tumors to cell death to help chemotherapy work better so that only smaller chemotherapy doses are required.
“ATX-101 can be used as the only treatment. It can stabilize the cancer as shown in the recently published studies, but the medicine can also help chemotherapy work even better so that you don’t have to have so much of it,” says Otterlei.
Despite the majority of the study participants not responding to their last heavy anticancer treatments before the study, 70% of the participants exhibited tumor growth cessation. For 40% of the patients in the study, tumor growth stopped for at least 4.1 months, with the longest tumor stabilization observed in one patient for over 29 months.
The only potential safety risk from the new drug was an allergy-type reaction to the medicine. Along those lines, mild and moderate itching and welts were seen in 64% of the treated patients, however, no serious adverse reactions were observed.
“Disease stabilization can probably be attributed to ATX-101, considering that 96% of the patients had progressive disease at study entry, 80% were refractory to the most recent systemic treatment, and most patients were heavily pretreated,” say Millward and colleagues.
Future Success in Clinical Trials Could Put ATX-101 on the Market in the Next Five Years
While these results sound promising, ATX-101 still has to go through phase II and phase III clinical trials before submission to the FDA for drug approval. Phase II clinical trials typically entail using larger patient sample sizes (100 to 300 people) to determine if a drug has efficacy. The next step in the FDA’s drug approval process, phase III clinical trials, enroll up to 3,000 participants and cost much more.
According to a recent press release, testing the drug’s anticancer effectiveness has already entered phase II clinical trials. Lots of drugs that are moderately effective go by the wayside during phase II and phase III clinical testing, though.
“A lot of medicines might work but don’t make it through the development process. The pharmaceutical industry doesn’t take on any projects they can’t profit from. What we develop has to work slightly better than current treatments, and preferably be cheaper to produce and have fewer side effects. Only then can an expensive development run pay off. It’s been a long run, and there’s still a long way to go,” says Otterlei.
If ATX-101 is successful in future clinical trials, it would enter the market as the first non-chemotherapeutic drug that targets multiple types of cancer while leaving healthy cells alone. Yet, since phase II clinical trials usually last a few months to a few years and phase III clinical trials often last one to four years, it may take over five years for patients to reap ATX-101’s anticancer benefits.
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