As of April 16, 2021, there were 2,073 cell therapy drugs in development worldwide, of which CAR-T therapies accounted for 1,164, occupying a dominant position with an annual growth rate of 35% [1]. CAR-T cell therapy is an individualized treatment modality. Significant variations exist in manufacturing processes, platforms, and patient-derived cells across different research institutions, highlighting the necessity of standardized CAR-T treatment. CAR-T therapy has gradually transformed the treatment landscape for lymphoma [2]. Using lymphoma as an example, this article provides a comprehensive overview of the full clinical process of CAR-T therapy.

(Figure 1: Schematic diagram of the overall CAR-T treatment process)

I. Full-Process Management of CAR-T Therapy

01 Pre-CAR-T Treatment uation

How do cancer patients know whether their condition is suitable for CAR-T therapy? There are multiple clinical criteria. Taking the Chinese Society of Clinical Oncology (CSCO) Guidelines for the Management of Infections Related to CAR-T Cell Therapy in Hematological Malignancies and Immune-Targeted Therapy as an example, as shown in Figure 2, patients should undergo medical history collection, physical examination, laboratory tests, and imaging studies under the guidance of physicians. Based on the results and physical indicators, doctors assess whether the patient meets the treatment criteria.

(Figure 2: CSCO uation guidelines)

In addition, the ECOG performance status scale is commonly used to assess patients' functional status. The ECOG scale is an important tool for uating the performance status and prognosis of cancer patients [3]. It divides patients into six grades based on activity level and physical condition, as shown in Figure 3. Higher scores indicate poorer physical status. Generally, patients with a score of 3 or higher may not be suitable for treatments such as chemotherapy. Other criteria include functional assessment of lymphoma-involved organs (e.g., compression, obstruction, ulceration, bleeding) and other organ function uations.

(Figure 3: ECOG performance status scale [5-point method])

02 Peripheral Blood Mononuclear Cell Collection

Before collecting peripheral blood mononuclear cells (PBMCs) from the patient, the patient's physical condition and blood cell status must still be uated to determine whether the patient's own T cells meet the requirements for autologous CAR-T cell manufacturing. If the activity is too poor, allogeneic T cells from healthy donors may be considered. Many factors can affect lymphocyte collection, primarily determined by the following biochemical factors. First, lymphotoxic drugs should be avoided before apheresis to prevent T-cell collection failure, and immunosuppressants should also be avoided as much as possible to prevent reducing immune system activity. Granulocyte colony-stimulating factor (G-CSF) induces stem cell mobilization, and stem cells in leukapheresis products carry a risk of malignant transformation during viral transduction for genetic modification; therefore, G-CSF should be discontinued before leukapheresis. Corticosteroids cause rapid depletion of lymphocytes in the circulation; low-to-moderate doses may cause mild lymphopenia. Ibrutinib can selectively inhibit Th2 responses and reduce PD-1 expression on T cells, potentially enhancing CAR-T cell function; therefore, Bruton's tyrosine kinase (BTK) inhibitors can be continued until cell separation, and studies on concurrent use with CAR-T cells are ongoing [4].

Before apheresis, clinicians must weigh the urgency of apheresis against the need for chemotherapy. Currently, considering the potential clinical benefit of CAR-T therapy, the ideal time for apheresis may be at the time of confirmed relapse, as certain chemotherapies are not conducive to apheresis or may need to be delayed to allow lymphocyte recovery [5].

(Figure 4: Washout periods for various types of therapy)

03 Bridging Therapy and Lymphodepleting Chemotherapy

Bridging therapy may be administered after PBMC collection and before CAR-T cell infusion; it does not include lymphodepleting chemotherapy. Its purpose is to prevent rapid disease progression, reduce tumor burden, and alleviate tumor-related symptoms. If CAR-T cell turnaround time is very short, bridging therapy may be omitted in cases of stable disease with low tumor burden. If the physician determines during CAR-T cell manufacturing that tumor progression may affect cell infusion, bridging therapy may be considered. Specific treatment regimens are shown in Figure 5.

CSCO Guidelines³ – Grade I Expert Recommendations: Chemotherapy, targeted therapy, immunotherapy, radiotherapy, etc. Rituximab, Obinutuzumab, Gemcitabine, Oxaliplatin, glucocorticoids, Etoposide, Cyclophosphamide, Cytarabine, or novel targeted therapies such as Lenalidomide or Ibrutinib.

NCCN Guidelines⁴ – Generally one or more cycles are required until the CART cell product becomes available:

DHAP + platinum ± Rituximab

GDP ± Rituximab or (Gemcitabine, Dexamethasone, Carboplatin) ± Rituximab

GemOx ± Rituximab

ICE ± Rituximab

Polatuzumab vedotinpiiq ± Rituximab ± Bendamustine (Bendamustine should only be considered/administered after leukapheresis)

Examples of treatment regimens for hematological lymphomas

When selecting bridging therapy for lymphoma patients, factors to consider include response to prior chemotherapy and immunochemotherapy, total tumor burden, distribution and of tumor involvement, patient physical condition, timing of apheresis, and pathological characteristics. The regimen should not be too intensive, as adverse effects may affect subsequent lymphodepleting chemotherapy and cell infusion. Bridging therapy must be completed at least 7 days before lymphodepleting chemotherapy [6].

To eliminate normal lymphocytes in the patient, remove immunosuppressive factors, and create an immune microenvironment favorable for CAR-T cell expansion, lymphodepleting chemotherapy is required before CAR-T cell infusion. The commonly used regimen is fludarabine + cyclophosphamide (FC regimen). After chemotherapy, the patient's immune level drops significantly, and infection prevention is critical during this period. Common infection prevention and control measures are shown in Figure 6.

(Figure 6: Infection prevention measures after lymphodepleting chemotherapy)

04 CAR-T Cell Infusion

Before CAR-T cell infusion (before thawing the CAR-T cell product), a comprehensive reassessment of the patient's clinical status is required, including vital signs (temperature, blood pressure, oxygen saturation, heart rate), presence of active infection, and organ function. Active infection and hypotension requiring vasopressor support are contraindications to CAR-T cell infusion, and infusion should be delayed until the infection or hypotension is completely treated or controlled.

(Figure 7: Product schematic)

(Figure 8: Infusion schematic)

CAR-T cell infusion is a critical step and requires fulfillment of many clinical conditions, such as establishing central venous access, preferably using dual-lumen or triple-lumen catheters for intravenous fluids and potential vasopressor use; electrocardiographic monitoring for severe arrhythmias, and additional monitoring based on clinical indications; according to standard institutional guidelines, tumor lysis prophylaxis and monitoring are recommended for patients with high tumor burden and aggressive histology; seizure prophylaxis should be initiated on the day of CAR-T cell infusion for products known to cause CAR-T cell-related neurotoxicity [7].

Before CAR-T cell infusion, product information should be checked, the product thawed, the infusion rate adjusted, and cell infusion initiated. The entire process from thawing to completion of infusion should generally be completed within 30 minutes. The start and end times of infusion should be recorded, and the patient's blood pressure, heart rate, and other vital signs should be monitored for any adverse reactions.

05 Post-Infusion Patient Monitoring and Adverse Event Management

After infusion, specialists will conduct toxicity monitoring and efficacy uation. Continuous monitoring is recommended from day 0 to day 28 post-infusion, with testing methods as shown in Figure 9. Monitoring recommendations for days 28–100 post-infusion are also shown in Figure 9.

(Figure 9: Monitoring recommendations for days 0–28 post-infusion)

After infusion, patients commonly experience adverse events such as cytokine release syndrome, neurotoxicity, cardiovascular toxicity, cytopenia, and tumor lysis syndrome. Clinical management protocols for these adverse events are now well established.

Cytokine Release Syndrome (CRS): An exaggerated physiological response caused by activation of infused or endogenous T cells and other immune cells triggered by immunotherapy. IL-6/IL-6R are the primary mediators of CRS. Massive activation of lymphocytes or bone marrow cells releases inflammatory cytokines (e.g., IFN-γ, IL-6, TNF-α, IL-2), leading to systemic SIRS, shock, and vascular leakage. Common CRS manifestations are shown in Figure 10.

(Figure 10: Main manifestations and severe CRSrelated events)

Clinically, CRS is graded into four severity levels, with different management strategies for each level.

(Figure 11: CRS grading criteria)

(Figure 12: Management of different grades of CRS)

Neurotoxicity or ICANS: Central nervous system pathology and dysfunction resulting from immunotherapy or secondary to T-cell infusion or activation/response of endogenous immune effector cells. Common clinical manifestations include encephalopathy, tremor, dizziness, aphasia, and delirium; severe life-threatening events include seizures, leukoencephalopathy, and cerebral edema [8,9]. Neurotoxicity also has specific grading and management protocols.

(Figure 13: Neurotoxicity grading)

Cardiovascular Complications: Occur in 10%–20% of CAR-T-treated patients. Risk factors for CAR-T cardiotoxicity include ≥ Grade 2 CRS, high disease burden, and pre-existing cardiac dysfunction from prior exposure to cardiotoxins (including anthracyclines, radiotherapy, and tyrosine kinase inhibitors). Comprehensive cardiovascular assessment before CAR-T cell infusion, appropriate monitoring, and risk reduction strategies can reduce cardiovascular complications.

Tumor Lysis Syndrome (TLS): A syndrome caused by massive tumor cell lysis releasing cellular contents and metabolites, manifesting as hyperuricemia, hyperphosphatemia, hypocalcemia, hyperkalemia, acute uric acid nephropathy, and other clinical features.

06 Long-Term Follow-Up After Infusion

Long-term follow-up should be conducted by a multidisciplinary team (CAR-T physician, disease-specific specialist, long-term follow-up nurse, data manager, clinical researcher) to monitor disease status and late effects. Prolonged cytopenia, hypogammaglobulinemia, and infections are common; neurological complications and pulmonary toxicity increase mortality risk; secondary malignancies are rare.

(Figure 14: Recommended tests for longterm followup outpatient visits)

II. Shenzhen Cell Valley Clinical Cell Product Services

Shenzhen Cell Valley has collaborated with multiple hospitals, including Shenzhen Union Hospital of Huazhong University of Science and Technology and Guangzhou Women and Children's Medical Center, on CAR-T clinical research, providing high-standard CAR-T cell products for over 30 clinical patients with notable efficacy. From the day of receiving patient blood samples, cell manufacturing can be completed in approximately 12 days. Fresh formulations can be transported within the province at 2–8°C in 50 mL infusion bags; cryopreserved formulations are available for deliveries outside the province.

(Figure 15: Clinical-grade CAR-T cell manufacturing process)

Shenzhen Cell Valley provides a full-service, dedicated support model, helping patients and physicians focus on treatment. The team has clear division of responsibilities to ensure seamless coordination at every stage.

(Figure 16: Shenzhen Cell Valley full-process service model)

References:

[1] Upadhaya S, et al. Nat Rev Drug Discov. 2021 Jul;20(7):503-504.

[2] LiX, et al. Cell Mol Immunol. 2022;19(1):122-124.

[3] Oken MM, et al. Am J Clin Oncol. 1982 Dec;5(6):649-55.

[4] Ying ZT, et al. Principles of full-process management of chimeric antigen receptor T-cell therapy for lymphoma at Peking University Cancer Hospital. Leukemia·Lymphoma. 2021;30(11):674-684. [in Chinese]

[5] Hayden PJ, et al. Ann Oncol. 2022;33(3):259-275.

[6] Yakoub-Agha I, et al. Haematologica. 2020;105(2):297-316.

[7] NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®). Management of Immunotherapy-Related Toxicities. 2022 v1.

[8] Strati P, et al. Blood Adv. 2020 Aug 25;4(16):3943-3951.

[9] Lee DW, et al. Blood. 2014 Jul 10;124(2):188-95.