Roche’s Phase III Trial of ES-SCLC Immunotherapy Fails to Extend Progression-Free Survival

Roche recently announced that tiragolumab, an investigational human monoclonal antibody designed for anti-TIGIT immunotherapy, has failed in the Phase III SKYSCRAPER-02 study for small cell lung cancer (SCLC).

In 490 SCLC patients receiving the first-line treatment, the combination of tiragolumab with the PD-L1 immune checkpoint inhibitor Tecentriq (atezolizumab) and chemotherapy failed to improve progression-free survival (PFS). Moreover, an interim analysis of overall survival data at another co-primary endpoint found that the planned final analysis was unlikely to achieve any statistical significance.

Related Article: New Research on Neoantigens and Tumor-targeting T-cells Marks Paradigm Shift in Countering Solid Tumors

Tecentriq, An Immune Checkpoint Inhibitor, Has Yet to Gain Ground

T cell immunoreceptor with Ig and ITIM domains (TIGIT) is an inhibitory receptor expressed on several types of lymphocytes. Like PD-L1, it is believed to act as a molecular brake to stop T cells from attacking tumors, and tiragolumab is currently the leading drug targeting immune checkpoints. The CITYSCAPE clinical trial of tiragolumab and Tecentriq as a first-line treatment for non-small cell lung cancer (NSCLC) in 2021 showed a 38% improvement in PFS with the combination compared to using Tecentriq alone, but new data suggest that this model may not be applicable to all cancers.

Roche stated that the SKYSCRAPER-02 study demonstrated that the combination of both drugs in conjunction with chemotherapy did not improve PFS in patients with extensive-stage SCLC (ES-SCLC) compared with the use of Tecentriq plus chemotherapy. Another goal of improving overall survival was also not achieved in the interim analysis and the situation is unlikely to change with additional follow-up actions.

Roche is still investigating the neoadjuvant and adjuvant use of tiragolumab and Tecentriq in non-small cell lung cancer (NSCLC). This combination was once considered a potentially stellar treatment worth over a billion USD.

Future of Dual Immunotherapy Challenged

ES-SCLC is therapeutically challenging, while the combination of Tecentriq plus chemotherapy remains the standard treatment for patients. Despite the setback in recent research that has dealt a blow to Roche’s attempts to prove that combining two immunotherapies can be superior to a single one, the proportion of patients who have responded to the treatment has increased.

Levi Garraway, Roche’s Chief Medical Officer, said the SKYSCRAPER-02 results were disappointing because it hoped to continue building on Tecentriq’s progress in ES-SCLC, which remains a difficult disease to treat.

SCLC is the most aggressive form of all lung cancers, accounting for about 15% of all cases, and is characterized by rapid progression and low survival rates. In 2020, Imfinzi (durvalumab) from AstraZeneca (AZ) joined the battle against the disease as a first-line treatment in conjunction with chemotherapy.In addition, there is fierce market competition for anti-TIGIT drugs, among Merck Sharp & Dohme (MSD), Bristol Myers Squibb (BMS), Agenus, Gilead, Arcus, GlaxoSmithKline (GSK), iTeos Therapeutics and Mereo Biopharma, with all having anti-TIGIT drugs in clinical trials.

Written by Ula Yang/ Translated by Richard Chau

Author

GeneOnline Team