Pfizer Inc. (PFE), which is developing immuno-oncology (I-O) candidate Avelumab with Merck KGaA, has altered the design of its phase 3 trial to include progression-free survival (PFS) and overall survival (OS) and also limited the patient group to include only high PD-L1 patients instead of the earlier design which was open to patients with any PD-L1 level.

PFS is the length of time during and after the treatment of a disease, such as cancer, that a patient lives with the disease but it does not get worse. OS is the duration of time from either the date of diagnosis or the start of treatment for a disease, such as cancer, that patients diagnosed with the disease are still alive.

The changes reduce the target patient group to a smaller subset of the original trial, they have also delayed the planned trial outcome until April 2019 from , against the earlier expected completion around August 2017.

The late stage trial, which is recruiting patients, is evaluating Avelumab as a first-line monotherapy for treating non-small cell lung cancer (NSCLC) patients with programmed death ligand 1+ (PD-L1+) tumors.

Too Late for Trial Changes?

The changes to the trial, which also includes increasing the number of trial patients to 1,095 from 420, may be a pragmatic move by Pfizer, learning from the past problems faced by other I-O drug makers in developing a first-line monotherapy for lung cancer.

Last June, Bristol-Myers Squibb’s (BMY) Opdivo failed to meet goals for use as a first-line treatment for lung cancer, which accounts for most number of cancer deaths in the U.S. Following the failure, Bernstein Analyst Tim Anderson said that trial failure “likely reflects the fact that BMY pushed the envelope too far in designing its trial,” and combination therapies may be the way forward. (See also, Roche, Bristol-Myers Battle for Cancer Drug Dominance.)

However, the changes to the Avelumab trial may be too late, as competitors are surging ahead. Merck & Co Inc.’s (MRK) Keytruda, Roche AG’s (RHHBY) Tecentriq and AstraZeneca PLC’s (AZN) Durvalumab are advancing further which may render Pfizer’s Avelumab lagging behind as a first line therapy for lung cancer. (See also, Novartis Lung Cancer Drug Succeeds in Trial.)

Though Pfizer and Merck KGaA plan to file for Avelumab as a second-line lung cancer therapy later this year, the segment is crowded with Bristol-Myers, Roche and Merck already having approvals for their respective therapies. If approved, Avelumab will enter a highly competitive space even as a second line treatment.

Competitors like Keytruda and Tecentriq also have an edge over Avelumab (and Opdivo) as they need less frequent dosing at once per three weeks, compared to the latter’s once per two weeks dosing schedule. 

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