- Although triple-negative breast cancer is challenging to treat, some hope may be on the horizon thanks to a cancer-killing virus called TVEC (thalimogene laherparepvec).
- In a phase 2 clinical trial, 45.9% of patients who received TVEC injections directly into tumor during chemotherapy there were no signs of cancer after surgery.
- The next step is to conduct a phase 3 clinical trial to confirm the efficacy of TVEC for triple-negative breast cancer in a larger study population.
Triple negative breast cancerwhich constitutes
This means that the tumor cells do not respond to hormone therapy or drugs that target HER2.
Currently, the preferred treatment approach for triple-negative breast cancer is neoadjuvant chemotherapy, a type of chemotherapy given before the main treatment for the cancer, such as surgery or radiation therapy.
Doctors administer it to reduce the size of a tumor, making it easier to remove that tumor with surgery, or to make radiation therapy more effective.
Researchers in Moffitt Cancer Center in Florida are looking to improve the treatment of triple-negative breast cancer by combining neoadjuvant chemotherapy with the use of a cancer-killing virus — called an “oncolytic virus” — called TVEC (talimogene laherparepvec).
In 2021, Dr. Hatem Soliman, a medical oncologist specializing in breast cancer, and colleagues at the Moffitt Cancer Center published the findings of a phase 1 study of TVEC combined with neoadjuvant chemotherapy in patients with triple-negative breast cancer. The results showed the safety and feasibility of this approach.
Now, Dr. Soliman and his team have conducted a phase 2 clinical trial to further investigate this treatment. The results of the phase 2 trial have been published in
Some patients with triple-negative breast cancer respond well to chemotherapy and have no signs of cancer in their tissues after treatment. This is known as a “pathological complete response”.
These patients are unlikely to develop cancer again in the next 5 years. Other patients do not achieve a complete response to chemotherapy and are much more likely to develop cancer in the next 2-3 years.
Researchers at Moffitt hoped to find a way to achieve a complete pathologic response in patients who might otherwise respond poorly to chemotherapy.
TVEC is already approved for the treatment of
Dr. Soliman and his team predicted that TVEC injections into triple-negative breast cancer tumors during neoadjuvant chemotherapy would result in a higher response rate to chemotherapy, as seen in melanoma.
When asked to explain what TVEC does to the body in triple negative breast cancer patients, Dr. Soliman said Medical News Today:
“Talimogene laherparepvec (TVEC) is oncolytic [cancer-killing] virus that can preferentially infect cancer cells when injected into a tumor. The virus will cause the tumor cells to explode, activating the immune system to attack the surrounding cancer cells. The use of TVEC in triple negative breast cancer tumors is a way to awaken the immune system against the tumor while cooperating with chemotherapy to better eradicate the tumors.
In the trial, 37 patients with stage 2 or 3 breast cancer, aged 27 to 66 years, received five intratumoral TVEC injections with neoadjuvant chemotherapy followed by surgery.
Of the 37 patients, 16 (45.9%) achieved a complete response, meaning they had no signs of cancer after surgery. Another eight patients had a small number of cancer cells left after treatment – known as a “near complete response”.
Of the 37 patients, 33 (89%) remained cancer-free at 2 years after treatment, and there was no recurrence in patients with a complete or near-complete response.
Adverse effects of treatment with TVEC and chemotherapy did not differ significantly from those expected from standard chemotherapy, except for higher rates of low-grade FEVERchills, headacheand pain at the injection site.
In one recent clinical trialThe researchers found that patients with early-stage triple-negative breast cancer who were given a combination of pembrolizumab – a drug that helps the individual’s immune system to fight cancer by preventing cancer cells from hiding – and neoadjuvant chemotherapy had a higher complete cure rate compared to those who received a placebo and neoadjuvant chemotherapy.
The results of this examination led to the Food and Drug Administration (FDA)
Although this is an important development, immunotherapy with pembrolizumab or similar drugs can cause the immune system to attack healthy cells, resulting in some Side effects.
Moffitt researchers hope that oncolytic viruses can enhance the immune response against tumors without causing as many side effects as immunotherapy drugs.
Dr. Howard L. Kaufmana surgical oncologist at Massachusetts General Hospital and lecturer at Harvard Medical School, said MNT:
The pembrolizumab/chemotherapy combination has significant toxicity, and the overall favorable safety profile of TVEC makes it a good agent for combination studies. The findings in the current study may also open the door to other locally delivered immunotherapy approaches as an important new area for clinical investigation into better treatments for high-risk triple-negative breast cancer patients.
For the moment,
So far, phase 1 and phase 2 trials with TVEC have shown promising results. The next step is to conduct a phase 3 clinical trial to confirm the efficacy of TVEC for triple-negative breast cancer among hundreds of people.
“While the results of this study are very important in establishing a potential role for TVEC in combination with chemotherapy for the neoadjuvant treatment of high-risk triple-negative breast cancer, a larger study with longer follow-up is needed to saw the full impact of the therapeutic intervention on survival endpoints,” said Dr. Kaufman.
“Such studies are expensive to conduct in both time and money, but the current study provides a strong rationale for supporting such a clinical trial in the future,” he noted.
Dr Soliman said MNT it would take 2-3 years to complete the phase 3 trial and make TVEC available to patients with triple-negative breast cancer.
