The candidate was analysed in combination with platinum-based chemotherapy, or antibody tremelimumab and chemotherapy, compared to chemotherapy alone, as primary treatment for patients at stage IV of cancer.
The combination of Imfinzi, tremelimumab and chemotherapy demonstrated a statistically significant and clinically meaningful overall survival (OS) compared to chemotherapy alone.
It also showed statistically significant improvement in progression-free survival (PFS), as already announced in October 2019.
Patients in this arm were treated with a short course of tremelimumab, an anti-CTLA4 antibody, over a 16-week period in addition to Imfinzi and standard chemotherapy.
The Imfinzi plus chemotherapy arm demonstrated a statistically significant improvement in PFS versus chemotherapy in the previous analysis, but not in OS.
Patients in the control arm were treated with up to six cycles of chemotherapy, while those in the experimental arms were treated with up to four cycles.
Both combinations were found to be safe.
“We’ve seen encouraging uptake of novel combinations in this setting and believe this new approach will add a further option for patients with high unmet medical need,” said Dave Fredrickson, executive vice president at the oncology business unit.
“We don’t think consensus has much in the way of sales in the metastatic setting for Imfinzi in lung cancer, given its dominant indication is in the earlier Stage III lung cancer setting and in small cell lung cancer (a rarer form of the disease). As such, any success in this setting would arguably be upside to the numbers,” analysts at Shore Capital commented.
However, the broker noted that success in this indication will depend on two factors: some more precise figures on what a “clinically meaningful” benefit means and education to convince clinicians to adopt this novel combination.
That’s because using a triple combination is likely to be more expensive and unfamiliar to physicians who are used to using Keytruda and chemotherapy as a double combination.
“The safety data from this study appears to suggest that adding tremelimumab to the Imfinzi and chemotherapy combination does not lead to a meaningful difference, which is important,” analysts added.
“It is encouraging to see an OS benefit with tremelimumab (the first time this has happened in a Phase III trial), but we think the market will wait to see the detailed clinical data before interpreting where a triple combination would ultimately sit in the treatment landscape. As such, we think the results will be cautiously welcomed but don’t anticipate a change to consensus on the back of this announcement.”
On the back of the PACIFIC trial, the stage III lung cancer setting remains Imfinzi’s main revenue driver, noted UBS, with the consensus forecast being for US$3.3bn of sales by 2025.
“This indication is starting to come under more attack from others (e.g. Roche’s Tecentriq+TIGIT combination), but the burden is on the challengers to demonstrate better results in head-to-head trials.”
Shares were flat at 7,718p on Friday morning.
–Adds analyst comment, shares–