NEJM: CAR-NK cell therapy works brightly in blood tumors!

. Recently, researchers from the University of Texas M.D. Anderson Cancer Center and others published the results of the
the first U.S. CLINICAL trial of CAR-NK cells
(NCT03056339) in the New England Journal of Medicine. Studies have shown that most patients who treated patients with recurrent or refractive non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL) with CAR-NK therapy, a source of cord blood, with extensive treatment, developed a clinical response withno major toxic effects.

researchers isolated NK cells from donated cord blood, and the reverse virus vector transduction of related genes enabled NK cells to express the ideal chimeric antigen receptor (CAR) to identify cancer-specific antigens (CD19 in this study). The NK cells used in the study were also modified to express the cytokine interleukin 15 15 and an enzyme that acts as a safety switch - the induced caspase 9, which enhances the growth and survival of NK cells in the body.

11 patients (5 Cases of CLL, 6 NHL patients) received single-dose cord blood-derived CD19 CAR-NK cells after lymphocytic removal chemotherapy, administered in one of three doses (1 x 10
5
, 1 x 10
6
, or 1 x 10
7
CAR-NK/kg weight). The first 9 patients were treated with CD19 CAR-NK cells and had a human leukocyte antigen (HLA) match before treatment, but the last two patients did not have an HLA match.


. The clinical response and post-relief treatment of CAR-NK therapy (source: NEJM)

efficacy,
8 (73%) responded to CD19-CARNK therapy within 30 days of treatment, and after 13.8 months of median follow-up, 7 of the 8 patients (3 CLL, 4 NHL) received full remission (CR)
no longer showed signs of disease. However, it should be noted that of the 8 patients who received remission after TREATMENT with CAR-NK, 5 received post-relief treatment.

safety, no patients develop cytokine release syndrome (CRS) or neurotoxicity. The level of inflammatory cytokines, including IL-6, did not increase after treatment. In addition, despite the use of donor cells, there was no graft-resistant host disease.

persistence, all dose levels of CAR-NK cells respondsignificantly within one month of being re-inducted into the patient and remain at low levels in the patient at least one year after the redelivery.

production, unlike the autonomous CAR-T therapy (which requires the patient's own T-cells to be genetically modified and the production process takes several weeks), since the CAR-NK cells used in this study are allogeneic, i.e. the cells originatate from healthy donors, it is expected to be produced and stored in advance so that they can be used immediately when needed. In addition, the umbilical cord blood of one donor can produce CAR-NK products for multiple patients.

summary, these data and information indicate that CAR-NK cell therapy has shown safety and efficacy in Phase I/II clinical trials for CD19-positive blood cancer patients. This encouraging initial results support further clinical studies to investigate whether CAR-NK cells of the same aosthele cord blood source can be used as treatment options for cancer patients.

. CAR-NK is one of the most anticipated engineering cell therapies after CAR-T. Based on the data reported by NEJM, there are several questions that are thought-provoking, such as what are the possible causes of very low CAR-NK toxicity? In addition to healthy donor umbilical cord blood, what other sources are CAR-NK? In addition to CD19, what other targets can be used to develop CAR-NK? Is CAR-NK as difficult to treat solid tumors as CAR-T? What else does CAR-NK need to be optimized for?


. Professor Yang Lin



with these questions,
Pharmaceutical Rubik's Cube interviewed Professor Yang Lin, chairman of Boshengji, which pioneered CAR-NK therapy in China as early as 2014. In an interview, Professor
Yang Lin said the data from the M.D. Anderson Cancer Center show edimen that car-NK cells have a strong potential to become a spot type (off-the-shelf) allogeneic cell therapy and are likely to be a major competitor to CAR-T therapy in the near future.

First of all, would you please comment on the data published by NEJM? Professor Yang Lin,

: "
Since the 2017 approval of two CD19 CAR-T cell therapy products, Yescarta and Kymriah, tumor cell therapy has been based on the patient's autoimmune cells as the main raw material, after in vitro activation, genetic modification, amplification culture and then back to the patient." There are three main problems with this cell preparation: (1) the patient's own T-cells as raw material, its quality is different, the preparation is prone to failure; In order to solve these problems, the development of allogeneic cell therapy products has become one of the main directions in the field of tumor immunocellular therapy in the past two or three years.in this NEJM, 8 (73%) of the 11 patients treated with an allogeneic CD19 CAR-NK cell retransmission were objective lysamy (OR), of which 7 patients achieved complete remission (CR), which was no less effective than cd19 CAR-T cell therapy products on the market. In addition, CAR-NK cytotoxic side effects are low, and no common cytokine storm (CRS) and neurotoxic side effects of CAR-T cell therapy were seen in all patients; In addition, CAR-NK cells prepared from umbilical blood sources can produce more than 100 doses per batch, with significantly lower production costs than CAR-T cells. Combined with these advantages, the literature's data demonstrate that CAR-NK cells have a strong potential to become a off-the-shelf allogeneic cell therapy and are likely to become a major competitor to CAR-T therapy in the near future.

. IN THE TRIALS REPORTED BY NEJM, CAR-NK SHOWED VERY LOW TOXICITY, WHAT DO YOU THINK IS THE POSSIBLE CAUSE?


. Professor Yang Lin:
I think that the reason slower car-NK toxicity is mainly related to the cell itself, which is not easy to cause excessive cytokine secretion. The most common toxic side effect of CAR-T therapy is cytokine storm (CRS), which is mainly caused by an increase in IL-6. The NEJM paper also mentions that THE IL-6 concentrations of CAR-NK subjects were low, and that another common side effect of CAR-T treatment was neurotoxicity, which was reported to be more associated with the secretion of IL-1, although the trial reported by NEJM did not appear to detect IL-1 concentrations, so it was not clear whether CAR-NK also produced a lower-1 factor.What other sources are CAR-NK in addition to using healthy donor cord blood? Professor Yang Lin,

: "First of
all, in terms of primary cells, in addition to the umbilical cord blood of healthy donors mentioned in the NEJM paper, the sources of cells for NK/CAR-NK cell therapy include the blood around the healthy donor and the placental tissue postpartum."

in addition, because NK tumor cell strain NK-92 also showed similar cell killing activity to normal NK cells, many NK-92 and CAR-NK-92 products are currently in the clinical testing stage, but due to safety factors, in the production process must undergo irradiation treatment to eliminate their inviviability, from the clinical data published so far, it seems to have limited efficacy.

in addition to the above cell sources, human pluripotent stem cells, such as hematopoietic stem cells from the source of umbilical blood, and induced pluripotent stem cells (iPSC), have been successfully induced into NK cells and have good cellular killing capabilities. Stem cells are considered the most promising source of cell therapy products because they provide an infinitely growing and stable source of cell quality. Last year, THE NK cells (FT500) obtained by fated pluripotent stem cell (iPSC) differentiation from Fate Therapeutics in the United States have officially entered Phase I clinically, and a second modified NK product (NK516) was approved by IND at the end of last year.

what are the targets available to develop CAR-NK at this time? How are these targets selected? Professor Yang Lin,

: "
targets currently used on CAR-T cells, such as CD19, BCMA, and other targets, can be used in CAR-NK therapy, so CAR-T and CAR-NK are very similar in target selection strategies. The trial, reported by NEJM, chose CAR-T's most common CD19 as the first target, and is a proof-of-concept approach that effectively compares car-T and CAR-NK differences, and as far as I know, the BCMA-CAR-NK-NK-project of the same research team at M.D. Anderson Cancer Center is also accelerating.

note that, I think that, unlike CAR-T, which has significant clinical efficacy in the treatment of B-cell cancers, CAR-NK cells have a strong advantage in the treatment of T-cell malignant tumor-related indications (e.g., acute T-lymphocytic leukemia and T lymphocyte lymphoma). There are two major bottlenecks in the use of CAR-T cells to treat T-cell malignancies: (1) If the use of the patient's autologous CAR-T cell treatment, easy to have tumor T cell contamination problem; The use of allogeneic back-to-transmission CAR-NK cells can effectively avoid these two problems, so to carry out the CAR-NK project, I recommend that priority be applied to T-cell malignant tumors such as adaptation.

does CAR-NK face the same challenges as CAR-T when it comes to treating solid tumors? Professor Yang Lin,

: "
yes, one of the main difficulties in the treatment of solid tumors is the heterogeneity of the tumor, so that neither CAR-T nor CAR-NK can completely remove all solid tumor cells; Summarizing the above two points, I think that to overcome the difficulties of solid tumors, whether CAR-T or CAR-NK need to be further modified, or use other drugs to achieve better tumor removal results. When did

when did Bosanji start CAR-NK research and development? Are there any difficulties in the research and development process?


. Professor Yang Lin:
Boshengji has been working on CAR-NK since 2014. However, the technology used at the time was similar to That of Nantkwest, which used NK92 cells as an effect cell for CAR-NK preparation. On the basis of the successful establishment of large-scale preparation process, we have carried out POC clinical research on solid tumors and blood tumors, and achieved some results. However, nk92 cells have many limitations, in addition to the aforementioned need for irradiation treatment, including the body survival time is very short, only about 3 days, so the need to repeat multiple administrations; Therefore, CAR-NK therapy based on NK92 cells, due to the loss of cell drugs to achieve clinical efficacy of the most critical in vivo amplification and continuity of the two key properties, its clinical efficacy is greatly reduced. Coupled with repeated and high-dose administration requirements, the cost of treatment has also increased dramatically. Clinical new drug development, therapeutic efficacy is the basic requirements, if NK92-based CAR-NK products can not compete with CAR-T, then such product competitiveness and vitality will be very poor. In light of this, Boshengji suspended CAR-NK research based on NK92 cells in 2017. However, iso-emerging cell products are still bosanji's pursuit of the goal, so Boshengji is actively developing a more competitive and viable hetero-expression cell therapy - CAR-Xenon T, and has made encouraging progress, is currently launching POC clinical trials and IND declaration preparations.

what other areas do you think CAR-NK needs to be optimized, or what remains to be overcome?


. Professor Yang Lin:
the results of the NEJM report, I think there is something that researchers need to explore further. First, 11 patients in this clinical trial used fresh- and infusion NK cells, and if they want to truly become a spot-type product, the researchers need to confirm that they have frozen.