Evaluation of step A did not support addition of pembrolizumab in step B

With the introduction of checkpoint inhibitors substantial improvements have been made in the treatment of malignant melanoma (MM). Despite this still a a subset of patients, approximately 50 %, experience no response to therapy.

One of the strategies to overcome these obstacles have been ACT with tumour infiltrating lymphocytes (TILs). Most TIL based ACT products are non-specifically expanded providing growth preference to co-infiltrated virus specific T cells, and it is currently challenging to expand T cells in an antigen-specific manner, while at the same time obtaining the ideal functional characteristics for specific and strong tumour-killing capacity with sufficient persistence.

In this phase I trial artificial antigen-presenting scaffolds for antigen-driven T cell expansion are used. These scaffolds will generate a MASE-T cell product enriched for selected specificities towards antigens known to be expressed by melanoma cells The aim of the study is to demonstrate that treatment with af MASE-T cell product i safe and feasible. Further the study will elucidate whether treament with the MASE-T cell product leads to objective responses and improves progression free survival (PFS).

There are around 350-400 new cases of patients with metastatic melanoma (MM) per year in Denmark. MM is a very aggressive cancer with a poor prognosis. Traditional oncological treatments such as surgery, chemotherapy and radiation therapy have a poor effect, and the 5-year overall survival has hitherto been less than 10 %.Substantial improvements have been made in the treatment of MM; especially immunotherapy is showing promising results with checkpoint inhibitors (CPI) such as programmed cell death protein 1 (PD-1) and Cytotoxic T Lymphocyte-associated Antigen 4 (CTLA-4) blocking antibodies administered as standard treatment in the frontline. The 5-year overall survival has now reached 52 %, 44 % and 26 % in nivolumab/ipilimumab, nivolumab, and ipilimumab respectively. However, a subset of patients - approximately 50 % experience no response to therapy, with clear primary resistance. One of the strategies to overcome these obstacles have been ACT with tumour infiltrating lymphocytes (TILs). A crucial condition for optimal ACT based on TILs is the generation of sufficient numbers of tumourreactive T cells. However, the expansion of TILs requires extensive ex vivo culturing often at the cost of T cell differentiation and functional activity. Most TIL based ACT products are non-specifically expanded providing growth preference to co-infiltrated virus specific T cells, and it is currently challenging to expand T cells in an antigen-specific manner, while at the same time obtaining the ideal functional characteristics for specific and strong tumour-killing capacity with sufficient persistence. Recent data suggest that the majority of tumour specific T cells responsible for tumour rejection under CPI are recruited from peripheral blood and lymph system, while not present in the tumour prior to treatment. This is supported by the finding that most tumour resident T cells are dysfunctional.

To overcome the current limitations in the treatment of malignant melanoma artificial antigen-presenting scaffolds for antigen-driven T cell expansion, generating a MASE-T cell product enriched for selected specificities towards antigens known to be expressed by melanoma cells has been designed. The antigen-scaffolds will ensuring optimal T cell stimulation by mimicking the in vivo stimulation of T cells by dendritic cells in the lymph nodes. The scaffolds contain both the antigen specific element - in the form of a peptide-MHC molecule and cytokine (IL2 and IL21), to provide growth and functional signals to the antigen specific T cell. As a result of this T cell expansion strategy, we can obtain a T cell product enriched for tumourantigen specific T cells. Superior functional activity towards tumor cells and antigen recognition compared to conventional T cell expansion strategies has been demonstrated in-vitro. Importantly, antigen-specific T cells in the MASE-T cell product possess a 'younger' phenotype, which has previously been described to correlate with improved in vivo persistence.

The study is a phase 1, non-randomized study. The trial will be conducted in two parts (A and B). Patients will be treated as followed:

• Part A (6 patients): Lymphodepleting chemotherapy (cyclophosphamide 500 mg/m2/day i.v. on day -4, -3, -2 and fludarabine 30 mg/m2/day i.v. on day -4, -3) followed by i.v. infusion of the MASE-T product on day 0. If the production of the MASE-T cell product was feasible for the majority (≥50%) of patients intended to treat in Arm A and the toxicity was acceptable, six patients will further be included in part B.
• Part B (6 patients): Lymphodepleting chemotherapy (cyclophosphamide 500 mg/m2/day i.v. on day -4, -3, -2 and fludarabine 30 mg/m2/day i.v on day -4, -3) followed by i.v infusion of the MASE-T product on day 0. Pembrolizumab 2 mg/kg will be administered on day -1 and day +21.

The primary objective is to evaluate the safety and feasibility of the MASE-T treatment alone or in combination with Pembrolizumab in patients with stage IV metastatic melanoma according to Common Terminology Criteria for Adverse Events (CTCAE version 5.0).

The secondary objectives are to evaluate T cell profile and persistence in vivo from tumor biopsies and blood samples as well as evaluation of the clinical efficacy of the treatment according to RECIST 1.1 and iRECIST. In addition, best overall response (BOR), duration of response (DOR), overall survival (OS), progression-free survival (PFS) will be monitored.

Inclusion Criteria:

1. Age ≥ 18 ≤ 75

2. Progressive disease on or after anti-PD-1/anti-PD-L1 monotherapy or progressive disease on or after anti PD-1 plus anti-CTLA-4 therapy

3. The patient has histologically confirmed metastatic melanoma

4. HLA-A2 positive

5. At least one measurable parameter according to RECIST version 1.1 guidelines

6. ECOG performance status of 0 or 1

7. No significant toxicity from previous cancer treatments (CTC ≤ 1)

8. Women of childbearing potential: Negative serum pregnancy test and must use effective contraception. This applies from screening and until 6 months after treatment. Birth control pills, spiral, depot injection with gestagen, subdermal implantation, hormonal vaginal ring and transdermal depot patch are all considered effective contraceptives

9. Men with female partner of childbearing potential must use effective contraception from screening and until 6 months after treatment. Effective contraceptives are as described above for the female partner. In addition, documented vasectomy and sterility or double barrier contraception are considered effective contraceptives

10. Signed statement of consent after receiving oral and written study information

11. Willingness to participate in the planned treatment and follow-up and capable of handling

12. The patient has met the following haematological and biochemical criteria:

    1. AST and ALT ≤2,5 X ULN or ≤5 X ULN with liver metastases
    2. Serum total bilirubin ≤1,5 X ULN or direct bilirubin ≤ ULN for patient with total bilirubin level > 1,5 ULN
    3. Serum creatinine ≤1,5 X ULN
    4. ANC (Absolute Neutrophil Count) ≥1,000/mcL
    5. Platelets ≥ 75,000 /mcL
    6. Hemoglobin ≥ 9 g/dL or ≥ 5.6 mmol/L

Exclusion Criteria:

1. Another malignancy or concurrent malignancy unless disease-free for 3 years
2. Requirement for immunosuppressive doses of systemic corticosteroids (>10 mg/day prednisone or equivalent) or other immunosuppressive drugs within the last 3 weeks prior to screening
3. Prior treatment with adoptive transfer of Tumor Infiltrating T cells (TIL)
4. Grade 3-4 adverse events upon treatment with PD-1 checkpoint inhibitors (only phase B)
5. The patient has CNS metastases and/or carcinomatous meningitis
6. The patient has any condition that will interfere with patient compliance or safety (including but not limited to psychiatric or substance abuse disorders)
7. The patient is pregnant or breastfeeding
8. The patient has an active infection requiring systemic therapy
9. The patient has received a live virus vaccine within 30 days of planned start of therapy
10. Significant medical disorder according to investigator; e.g severe asthma or chronic obstructive lung disease, dysregulated heart disease or dysregulated diabetes mellitus.
11. Concurrent treatment with other experimental drugs
12. Any significant active autoimmune disease
13. Severe allergy or anaphylactic reactions earlier in life
14. Known hypersensitivity to one of the active drugs or one or more of the excipients.
15. Unrelieved lower urinary tract obstruction