IMpower133
IMpower133 was the first trial in decades to lengthen survival in extensive-stage small-cell lung cancer, by adding immunotherapy to chemotherapy.
Median OS 12.3 vs 10.3 months (HR 0.70); PFS 5.2 vs 4.3 months. Established chemo-immunotherapy as first-line standard (FDA March 2019). The IMbrella A extension reported the first five-year survival data for chemo-immunotherapy in ES-SCLC, with a small tail of long-term survivors in the atezolizumab arm. Benefit was independent of PD-L1 and TMB.
- Median 12.3 vs 10.3 months with Atezolizumab + CE compared with Placebo + CE; about 2 months longer for half the group.
- A median is a midpoint: half the people did better than this and half did worse, so it is not a prediction for any one person.
- Put another way, the treated group had about 30 percent lower chance of the event at any given time (hazard ratio 0.7, likely range 0.54 to 0.91).
- Overall survival counts deaths from any cause, so it is the most direct measure of whether a treatment helps people live longer.
- Median 5.2 vs 4.3 months with Atezolizumab + CE compared with Placebo + CE; about 0.9 months longer for half the group.
- A median is a midpoint: half the people did better than this and half did worse, so it is not a prediction for any one person.
- Put another way, the treated group had about 23 percent lower chance of the event at any given time (hazard ratio 0.77, likely range 0.62 to 0.96).
- This is a surrogate endpoint: it measures the cancer being controlled or absent on scans and tests, which often, but not always, translates into living longer.
- These results apply to the people the trial enrolled: First-line extensive-stage SCLC: carboplatin-etoposide + atezolizumab vs carboplatin-etoposide + placebo. People in a different situation may not see the same effect.
Numbers are from the trial as recorded here; see the source links in the table below. This is orientation, not medical advice: ask your team how closely the trial population matches you.
403 participants enrolled.
| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| Overall survivalprimary | Atezolizumab + CE | 201 | 12.3 months | 0.7 (0.54–0.91) | 0.007 | link |
| Placebo + CE | 202 | 10.3 months | ||||
| Progression-free survivalprimary | Atezolizumab + CE | — | 5.2 months | 0.77 (0.62–0.96) | — | — |
| Placebo + CE | — | 4.3 months |
Pages like this
not linked directly; found by shared links- TrialASTRUM-005
Shares Platinum + etoposide (EP / CE), Small-cell lung cancer.
- TrialCASPIAN
Shares Platinum + etoposide (EP / CE), Small-cell lung cancer.
- PairingChemo-immunotherapy induction → maintenance intensification (SCLC)
Shares Platinum + etoposide (EP / CE), Atezolizumab, Small-cell lung cancer.
- TrialIMforte
Shares Atezolizumab, Small-cell lung cancer.
- IdeaImmunotherapy downstaging to transplant with a safe washout
Shares Atezolizumab, Immune checkpoint inhibitors.
- PersonHeather A. Wakelee
Shares Atezolizumab, Immune checkpoint inhibitors.
- TermLimited-stage vs extensive-stage (small-cell lung cancer)
Shares Atezolizumab, Small-cell lung cancer.
- ProductTiragolumab
Shares Atezolizumab, Small-cell lung cancer, Immune checkpoint inhibitors.