DC vaccine generation
For vaccine production, DC were generated from PBMCs that had been derived from apheresis products collected from patients prior to treatment. At least 2 weeks prior to apheresis, patients received G-CSF (Granulocyte-colony stimulating factor) for 5 days, administered on an outpatient basis (subcutaneously). Apheresis was performed via a two-armed approach or via a temporary central venous catheter. The freshly collected cells were used to produce monocyte derived DC according to cGMP. Briefly, the collected cells were washed and plated in T175 flasks for 2 hours at 37C. Non- adherent cells were washed away while the remaining, adherent cells were incubated with GM- CSF and IL- 4 (1000 IU/mL) to mature monocytes into DCs.
After 5–7 days of culture, immature DCs were activated overnight with a maturation cocktail (IL- 1β 10 ng/mL, TNFα 10 ng/mL, IL-6 15 ng/mL and PGE2 1 μg/mL). The next day the mature DCs were harvested, washed and then pulsed with 3 μg/mL MART-1 peptide for 1.5 hours. The peptide pulsed DCs were washed and cryopreserved in two bags for the two doses to be administered on day 0 and day 21, in freezing solution containing 7.5% DMSO, and stored in the vapor phase of liquid nitrogen.
18 patients were randomized to TIL (n=10) or TIL +DC (n=8). All patients underwent non-myeloablative, lympho-depleting intravenous chemotherapy consisting of cyclophosphamide for 2 days (days −7 and −6) and intravenous fludarabine for 5 days (days −5 to −1) as inpatients before TIL infusion. Freshly harvested and washed autologous TILs were infused intravenously.
Patients randomized to the DC co-vaccine arm received a first dose of DC infused intravenously 4 hours post-TIL infusion (range of 98–478 x 106 MART-1 peptide-pulsed DC). High dose of 720 000 IU/kg intravenous IL-2 was administered every 8 hours on days 1 to 5. Doses were skipped if patients experienced grade III or IV toxicity because of high-dose IL-2, except for the reversible grade III toxicities that are common to high-dose IL-2.On day 21, the DC infusion was repeated for patients who had been randomly assigned to the DC arm. On days 22 to 26, high-dose IL-2 was given to all patients using the same procedure described for days 1 to 5.
The ORR was 30% for the 23 enrolled patients and was 39% for the 18 treated and evaluated patients. By treatment arm, in 23 randomized patients, the ORR was 25% in TIL alone arm and was 36% in the TIL+DC arm. In the 18 treated and evaluated patients, the ORR was numerically higher in the TIL+DC arm (4/8; 50%) compared with the TIL arm (3/10; 30%).
In the TIL arm, two patients experienced a PR (11 months, and 2 months), and one patient experienced a CR that lasted for 18 months. The remaining patients in the TIL arm had stable disease (SD) for <4 months or PD (three SD and three PD). In the TIL+DC arm, one patient achieved a CR (>137 months; was ongoing at last follow-up) and three patients achieved PRs; the three PRs had a response duration of 2, 7 and 8 months. The remaining four patients either had SD for <5 months or PD (two SD and two PD).
The median duration of response was 0.76 years in the TIL arm (95% CI 0.09 to 1.4 years) and was 0.81 years (95% CI 0.09 to 11.2 years) in the TIL+DC arm (online supplemental figure 2). Responses were ongoing in one of four (25%) patients in the TIL+DC arm and none of three (0%) patients in the TIL arm.
With a median follow-up of 2.2 years (range, 0.13– 10.22 years), the median OS duration was 2.6 years and the median PFS duration was 0.34 years in the whole cohort. The PFS duration was longer in the TIL +DC arm than in the TIL arm (0.49 years and 0.26 years, respectively). The OS duration was longer in the TIL arm than in the TIL +DC arm. (4.1 years and 2 years, respectively).
The combination of TIL +DC showed no difference in the persistence of MART-1 TIL compared with TIL therapy alone. Although more patients showed a clinical response to TIL+DC therapy.
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Scientific article publishing date 26/3/2021
Immucura identifier BSC21_065EN