She was in the terminal stage of disease so hence the approval of the experimental treatment , we don't know the long term effects or why it did not work consistently in other patients.
And as of 2019, the patient is still cancer free: https://emilywhiteheadfoundation.org/news/celebrating-7-year...
Here's the relevant quote:
> The Pennsylvania researchers said they were surprised to find any big drug company interested in their work, because a new batch of T-cells must be created for each patient — a far cry from the familiar commercial strategy of developing products like Viagra or cholesterol medicines, in which millions of people take the same drug.
> But Mr. Hoppenot said Novartis was taking a different path with cancer drugs, looking for treatments that would have a big, unmistakable impact on a small number of patients. Such home-run drugs can be approved more quickly and efficiently, he said, with smaller studies than are needed for drugs with less obvious benefits.
> “The economic model is totally acceptable,” Mr. Hoppenot said.
> But such drugs tend to be extremely expensive. A prime example is the Novartis drug Gleevec, which won rapid approval in 2001 for use against certain types of leukemia and gastrointestinal tumors. It can cost more than $5,000 a month, depending on the dosage.
> Dr. June said that producing engineered T-cells costs about $20,000 per patient — far less than the cost of a bone-marrow transplant. Scaling up the procedure should make it even less expensive, he said, but he added, “Our costs do not include any profit margin, facility depreciation costs or other clinical care costs, and other research costs.”
Specifically, countries that don't have a broken extremely-overinflated-pricing model for health care.
Also there are biohackers who synthesize their own insulin and even COVID-19 vaccines and test it on themselves. Their work may cause them more harm than good, but it's their bodies and they're free to experiment on it however they choose. When somebody has a terminal illness and is facing imminent death the risk calculus is very different where even taking the bargain basement biohacker version of a medication may make sense. (Though obviously this particular treatment is a bit different because it uses a modified HIV virus)
Not sure if it good or bad...
In fact, the body does this regularly. Cells frequently mutate to divide uncontrollably in the body, but are nearly always suppressed by the immune system. It is only when the tumor somehow manage to bypass the immune system or the immune system is sufficiently weakened that cancers can spread.
The mRNA cancer vaccine they're developing is for people who already have cancer. It's targeted based on the specific tumour the patient has, and basically primes the immune system to attack the cancer cells. They can't even develop the vaccine until the patient has the cancer it's fighting against.