Drug may best BSC in some high-risk MDS patients

Micrograph showing MDS

Results of a phase 3 trial suggest the small-molecule inhibitor rigosertib may improve overall survival (OS) in some patients with higher-risk myelodysplastic syndromes (HR-MDS).

Overall, researchers found no significant difference in OS between patients who received rigosertib and those who received best supportive care (BSC).

However, the data indicate that rigosertib can confer a survival benefit in certain subgroups of HR-MDS patients.

The results of this trial, known as ONTIME, were published in The Lancet Oncology. The trial was sponsored by Onconova Therapeutics, Inc., the company developing rigosertib.

The trial enrolled 299 HR-MDS patients. They had refractory anemia with excess blasts (RAEB)-1, RAEB-2, RAEB-t, or chronic myelomonocytic leukemia based on local site assessment. They had all failed treatment with a hypomethylating agent (HMA) in the past 2 years.

The patients were randomized (2:1) to receive rigosertib at 1800 mg per 24 hours via 72-hour continuous intravenous (IV) infusion, administered every other week (n=199), or BSC with or without low-dose cytarabine (n=100).

At a median follow-up of 19.5 months, there was no significant difference in OS between the treatment arms. The median OS was 8.2 months in the rigosertib arm and 5.9 months in the BSC arm. The hazard ratio (HR) was 0.87 (P=0.33).

However, the researchers said that subgroup analyses suggested rigosertib may provide a survival benefit over BSC in some HR-MDS patients. This includes:

• Patients younger than 75 years of age (HR=0.55, P=0.0010)
• Patients who received HMA therapy for 9 months or fewer (HR=0.54, P=0.0016)
• Patients with primary, rather than secondary, HMA failure (HR=0.72, P=0.060)
• Patients who were classified as “very high risk” according to the Revised International Prognostic Scoring System (HR=0.61, P=0.015)
• Patients with monosomy 7 (HR=0.26, P=0.0041)
• Patients with trisomy 8 (HR=0.28, P=0.0083).

The most common grade 3 or higher adverse events—in the rigosertib and BSC arms, respectively—were anemia (18% vs 8%), thrombocytopenia (19% vs 7%), neutropenia (17% vs 8%), febrile neutropenia (12% vs 11%), and pneumonia (12% vs 11%).

Twenty-two percent of patients in the rigosertib arm and 33% in the BSC arm died due to adverse events. Three deaths were attributed to rigosertib.

“Rigosertib was well-tolerated in patients with a high unmet medical need who have no approved therapeutic options,” said study author Guillermo Garcia-Manero, MD, of The University of Texas MD Anderson Cancer Center in Houston.

“We are impressed by the trend to notable efficacy in well-defined, well-balanced subgroups of HR-MDS patients with very poor prognosis. Based on these findings, we have designed the new phase 3 INSPIRE study with IV rigosertib, which is currently enrolling patients.”

INSPIRE is a randomized, controlled study designed to assess the efficacy and safety of IV rigosertib in HR-MDS patients under 80 years of age who had progressed on, failed to respond to, or relapsed after previous treatment with an HMA within the first 9 months of HMA treatment initiation.

The trial is expected to enroll approximately 225 patients, who will be randomized at a 2:1 ratio into 2 treatment arms: IV rigosertib plus BSC versus physician’s choice plus BSC. The primary endpoint is OS. Full details on the trial can be found on clinicaltrials.gov (NCT02562443).

Micrograph showing MDS

Results of a phase 3 trial suggest the small-molecule inhibitor rigosertib may improve overall survival (OS) in some patients with higher-risk myelodysplastic syndromes (HR-MDS).

Overall, researchers found no significant difference in OS between patients who received rigosertib and those who received best supportive care (BSC).

However, the data indicate that rigosertib can confer a survival benefit in certain subgroups of HR-MDS patients.

The results of this trial, known as ONTIME, were published in The Lancet Oncology. The trial was sponsored by Onconova Therapeutics, Inc., the company developing rigosertib.

The trial enrolled 299 HR-MDS patients. They had refractory anemia with excess blasts (RAEB)-1, RAEB-2, RAEB-t, or chronic myelomonocytic leukemia based on local site assessment. They had all failed treatment with a hypomethylating agent (HMA) in the past 2 years.

The patients were randomized (2:1) to receive rigosertib at 1800 mg per 24 hours via 72-hour continuous intravenous (IV) infusion, administered every other week (n=199), or BSC with or without low-dose cytarabine (n=100).

At a median follow-up of 19.5 months, there was no significant difference in OS between the treatment arms. The median OS was 8.2 months in the rigosertib arm and 5.9 months in the BSC arm. The hazard ratio (HR) was 0.87 (P=0.33).

However, the researchers said that subgroup analyses suggested rigosertib may provide a survival benefit over BSC in some HR-MDS patients. This includes:

• Patients younger than 75 years of age (HR=0.55, P=0.0010)
• Patients who received HMA therapy for 9 months or fewer (HR=0.54, P=0.0016)
• Patients with primary, rather than secondary, HMA failure (HR=0.72, P=0.060)
• Patients who were classified as “very high risk” according to the Revised International Prognostic Scoring System (HR=0.61, P=0.015)
• Patients with monosomy 7 (HR=0.26, P=0.0041)
• Patients with trisomy 8 (HR=0.28, P=0.0083).

The most common grade 3 or higher adverse events—in the rigosertib and BSC arms, respectively—were anemia (18% vs 8%), thrombocytopenia (19% vs 7%), neutropenia (17% vs 8%), febrile neutropenia (12% vs 11%), and pneumonia (12% vs 11%).

Twenty-two percent of patients in the rigosertib arm and 33% in the BSC arm died due to adverse events. Three deaths were attributed to rigosertib.

“Rigosertib was well-tolerated in patients with a high unmet medical need who have no approved therapeutic options,” said study author Guillermo Garcia-Manero, MD, of The University of Texas MD Anderson Cancer Center in Houston.

“We are impressed by the trend to notable efficacy in well-defined, well-balanced subgroups of HR-MDS patients with very poor prognosis. Based on these findings, we have designed the new phase 3 INSPIRE study with IV rigosertib, which is currently enrolling patients.”

INSPIRE is a randomized, controlled study designed to assess the efficacy and safety of IV rigosertib in HR-MDS patients under 80 years of age who had progressed on, failed to respond to, or relapsed after previous treatment with an HMA within the first 9 months of HMA treatment initiation.

The trial is expected to enroll approximately 225 patients, who will be randomized at a 2:1 ratio into 2 treatment arms: IV rigosertib plus BSC versus physician’s choice plus BSC. The primary endpoint is OS. Full details on the trial can be found on clinicaltrials.gov (NCT02562443).

Micrograph showing MDS

Results of a phase 3 trial suggest the small-molecule inhibitor rigosertib may improve overall survival (OS) in some patients with higher-risk myelodysplastic syndromes (HR-MDS).

Overall, researchers found no significant difference in OS between patients who received rigosertib and those who received best supportive care (BSC).

However, the data indicate that rigosertib can confer a survival benefit in certain subgroups of HR-MDS patients.

The results of this trial, known as ONTIME, were published in The Lancet Oncology. The trial was sponsored by Onconova Therapeutics, Inc., the company developing rigosertib.

The trial enrolled 299 HR-MDS patients. They had refractory anemia with excess blasts (RAEB)-1, RAEB-2, RAEB-t, or chronic myelomonocytic leukemia based on local site assessment. They had all failed treatment with a hypomethylating agent (HMA) in the past 2 years.

The patients were randomized (2:1) to receive rigosertib at 1800 mg per 24 hours via 72-hour continuous intravenous (IV) infusion, administered every other week (n=199), or BSC with or without low-dose cytarabine (n=100).

At a median follow-up of 19.5 months, there was no significant difference in OS between the treatment arms. The median OS was 8.2 months in the rigosertib arm and 5.9 months in the BSC arm. The hazard ratio (HR) was 0.87 (P=0.33).

However, the researchers said that subgroup analyses suggested rigosertib may provide a survival benefit over BSC in some HR-MDS patients. This includes:

• Patients younger than 75 years of age (HR=0.55, P=0.0010)
• Patients who received HMA therapy for 9 months or fewer (HR=0.54, P=0.0016)
• Patients with primary, rather than secondary, HMA failure (HR=0.72, P=0.060)
• Patients who were classified as “very high risk” according to the Revised International Prognostic Scoring System (HR=0.61, P=0.015)
• Patients with monosomy 7 (HR=0.26, P=0.0041)
• Patients with trisomy 8 (HR=0.28, P=0.0083).

The most common grade 3 or higher adverse events—in the rigosertib and BSC arms, respectively—were anemia (18% vs 8%), thrombocytopenia (19% vs 7%), neutropenia (17% vs 8%), febrile neutropenia (12% vs 11%), and pneumonia (12% vs 11%).

Twenty-two percent of patients in the rigosertib arm and 33% in the BSC arm died due to adverse events. Three deaths were attributed to rigosertib.

“Rigosertib was well-tolerated in patients with a high unmet medical need who have no approved therapeutic options,” said study author Guillermo Garcia-Manero, MD, of The University of Texas MD Anderson Cancer Center in Houston.

“We are impressed by the trend to notable efficacy in well-defined, well-balanced subgroups of HR-MDS patients with very poor prognosis. Based on these findings, we have designed the new phase 3 INSPIRE study with IV rigosertib, which is currently enrolling patients.”

INSPIRE is a randomized, controlled study designed to assess the efficacy and safety of IV rigosertib in HR-MDS patients under 80 years of age who had progressed on, failed to respond to, or relapsed after previous treatment with an HMA within the first 9 months of HMA treatment initiation.

The trial is expected to enroll approximately 225 patients, who will be randomized at a 2:1 ratio into 2 treatment arms: IV rigosertib plus BSC versus physician’s choice plus BSC. The primary endpoint is OS. Full details on the trial can be found on clinicaltrials.gov (NCT02562443).