FL

Lenalidomide plus rituximab versus rituximab monotherapy in previously-untreated FL: Results from a phase II trial

On 17 May, Emanuele Zucca from the Oncology Institute of Southern Switzerland, Bellinzona, CH, and colleagues, published results from a phase II trial in follicular lymphoma (FL) (NCT01307605), in Blood.1 This trial compared the efficacy and safety of rituximab monotherapy to rituximab plus lenalidomide in patients with previously untreated FL.

Rituximab in combination with chemotherapy is a standard of care treatment for patients with symptomatic advanced stage FL.2 The investigators sought to examine whether in previously untreated patients with FL, rituximab alone or with chemotherapy, is an effective treatment plan.

The primary endpoint of this open-label, randomized, multicentre trial was complete response (CR) rate at around six months following treatment. Secondary endpoints included overall response rate (ORR), CR rate at 30 months post treatment, progression-free survival (PFS), duration of response (DoR), time-to-next treatment (TTNT), overall survival (OS), and safety.

Study design & baseline characteristics
  • N = 154 patients with previously untreated Grade 1−3A FL with CD20 immunohistochemistry, stage II−IV not eligible for radiotherapy
  • Dosing:
    • Rituximab monotherapy (R arm; n= 77): eight cycles of intravenous R administration (375 mg/m2) at Day 1 of Week 1−4
      • In responding patients, R was repeated at Day 1 of Week 12−15
    • Rituximab + lenalidomide (RL arm; n = 77): eight cycles of R (as above) plus 15 mg of oral L daily, starting 14 days prior to R administration and daily until 14 days after the last R administration (18 weeks in total)
    • Randomization was stratified according to:
      • Histological grade (Grade 1−2 vs 3A)
      • Bulky disease (< 6 cm vs ≥ 6 cm)
      • FL International Prognostic Index (FLIPI) score (1−2 vs ≥ 3)
  • No R dose adjustments were allowed but L could be adjusted according to renal function and toxicity
  • Median patient age (range) in total cohort: 62 (26−85)
  • Male patients in total cohort: 47%

Table1. Key baseline characteristics:

Baseline characteristic

R arm

(n = 77)

RL arm

(n = 77)

Total cohort

(N = 154)

Ann Arbor stage

II

III

IV

 

10%

38%

52%

 

14%

38%

48%

 

12%

38%

50%

FLIPI score

Low risk

Intermediate risk

High risk

 

19%

34%

47%

 

27%

26%

47%

 

23%

30%

47%

FL histological grade

1

2

3a

 

23%

60%

17%

 

 

26%

58%

16%

 

25%

59%

16%

Bulky disease

< 6 cm

≥ 6 cm

 

60%

40%

 

58%

42%

 

59%

41%

Key findings
  • All R cycles (eight) were completed by:
    • R arm: 71% of patients
    • RL arm: 91% of patients
  • Number of patients completing treatment with the planned L dose (RL arm): ≥ 90% of patients
    • 29% patients in RL arm had at least one L dose reduction:
  • Treatment discontinuation due to insufficient response at week 10 occurred in:
    • R arm: 21% of patients
    • RL arm: 4% of patients
  • Median follow-up of the intention-to-treat (ITT) population (range): 4 (3.3−7) years

Table 2. Responses at Week 23 (ITT population) based on Independent Response Review (IRR):

 

R arm (n = 77)

RL arm (n = 77)

CR & unconfirmed CR (CRu)*

36% (95% CI, 26−48)

61% (95% CI, 49−72)

Partial response (PR)

21%

17%

Stable disease (SD)

9%

3%

Progressive disease (PD)

4%

1%

Not evaluable

30%

18%

* P = 0.001
  • The CR/CRu improvement seen with the addition of L was sustained over time
    • At a follow-up of 30 months the CR/CRu rate was 19% vs 42% (P = 0.001)
    • At a median follow-up of 4 years (R vs RL):
      • Median PFS rate was 2.3 vs0 years, (P = 0.035)
      • Median CR/CRu response was 3.0 years vs not reached (P = 0.055)
      • TTNT was 2.1 years vs not reached (P = 003)
      • OS was not significant: 91% (95% CI, 81−96) vs 90% (95% CI, 79−95)
    • However, multiple regression analysis revealed that CR/CRu rate at Week 23 was not associated with treatment regimen (P = 0.1094), FLIPI score (P = 0.9979), tumor bulk (P = 0.2672) or FL grade (P = 0.5797)
    • Cox proportional hazard modelling revealed that FLIPI score was associated with longer PFS (HR = 1.845; [95% CI, 1.148−962]; P = 0.0113)
    • Number of patients who started a second-line immunochemotherapy at the time of analysis:
      • R arm: 60% of patients
      • RL arm: 39% of patients
Safety
  • Treatment discontinuation due to toxicity occurred in:
    • R arm: n = 1 patient
    • RL arm: n = 13 patients (11 patients stopped L only)
  • Grade ≥ 3 adverse events (AEs) occurred in:
    • R arm: 22% of patients
    • RL arm: 56% of patients
  • Grade 3 and 4 neutropenia occurred in:
    • R arm: 7% of patients
    • RL arm: 23% of patients
  • No treatment-related deaths occurred during the trial in either arm
  • AEs more commonly observed in the RL arm:
    • Fatigue
    • Diarrhea
    • Skin rash
Conclusions

Lenalidomide in combination with rituximab led to a significantly better CR/CRu rate, longer PFS and TTNT, when compared to rituximab monotherapy in patients with previously untreated FL. However, there was no significant effect on OS.

References
  1. Zucca E. et al. Short regimen of rituximab plus lenalidomide in follicular lymphoma patients in need of first-line therapy. Blood. 2019 May 17. pii: blood-2018-10-879643. DOI: 10.1182/blood-2018-10-879643 [Epub ahead of print]
  2. Dührsen, U. et al. 2018. Rituximab maintenance therapy of follicular lymphoma in clinical practice. Cancer Med. 7, 2903–2912. DOI: 10.1002/cam4.1549
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