FDA Panel Supports Subcutaneous Rituximab for Blood Cancers

Sandra Horning, MD

The FDA’s Oncologic Drugs Advisory Committee (ODAC) unanimously (11-0) recommended approval of subcutaneous rituximab for the treatment of patients with certain blood cancers, according to Genentech, the manufacturer of the treatment.

The company explained in a statement that the novel co-formulation includes the identical monoclonal antibody as intravenous (IV) rituximab (Rituxan), along with the molecule hyaluronidase, which facilitates the delivery of medicine beneath the skin.

The proposed indications for the treatment include previously untreated follicular lymphoma (FL), previously untreated diffuse large B-cell lymphoma (DLBCL), relapsed or refractory low grade or follicular lymphoma, and previously untreated and relapsed or refractory chronic lymphocytic leukemia (CLL). A final approval decision is expected from the FDA by June 26, 2017.

“Subcutaneous rituximab can be administered in 5 to 7 minutes compared to an hour and a half or more for intravenous Rituxan,” Sandra Horning, MD, chief medical officer and head of Global Product Development at Genentech, said in a statement. “The significant reduction in administration time could especially benefit people with blood cancer who may receive years of treatment, and we are pleased the committee unanimously supported this new co-formulation.”

ODAC based its recommendation on a review of data from 5 clinical trials that included 2000 patients with the various blood cancers for which rituximab IV is currently approved. The results demonstrated that the efficacy, safety, and pharmacokinetics of the subcutaneous (SC) formulation were noninferior to IV rituximab.

The specific trials included in the clinical development program were as follows: SparkThera (NCT00930514), a phase Ib maintenance study in previously untreated or relapsed follicular lymphoma; SABRINA (NCT01200758), a phase III induction and maintenance study in previously untreated follicular lymphoma; SAWYER (NCT01292603), a phase Ib study in previously untreated CLL; MabEase (NCT01649856), a phase III study in previously untreated DLBCL; and PrefMab (NCT01724021), a phase III patient preference study in previously untreated follicular lymphoma and DLBCL.

As a sample of the pivotal data, the phase III MabEase trial evaluated SC (381 patients) versus IV (195 patients) rituximab in combination with CHOP chemotherapy in patients with previously untreated CD20-positive DLBCL. The overall response rate (ORR) was 71.8% in the IV arm versus 72.7% in the SC arm (P value not available). The complete response (CR) rates were 42.1% versus 47.0%, respectively. The hazard ratio (HR) for progression-free survival (PFS) was 1.23 (95% CI, 0.86-1.76; P = .280) and the HR for overall survival (OS) was 1.06 (95% CI, 0.68-1.65; P = 0.717).

The phase III SABRINA trial compared the rituximab formulations in combination with CHOP or CVP chemotherapy in previously untreated patients with FL. The ORR was 84.9% in the IV arm (205 patients) and 84.4% in the SC arm (205 patients; P = 0.8911). The CR rates were 32.2% versus 32.2%, respectively. The HR for PFS was 0.84 (95% CI, 0.57-1.23; P = 0.3696) and the HR for OS was 0.81 (95% CI, 0.42-1.57; P = 0.5398).

The phase Ib SAWYER trial compared the 2 formulations in combination with chemotherapy in previously untreated patients with CLL. The ORR was 80.7% in the IV arm (88 patients) and 85.2% in the SC arm (88 patients; P = 0.4227). The CR rates were 33% versus 26.1%, respectively. The HR for PFS was 0.89 (95% CI, 0.49-1.64; P = 0.7192) and the HR for OS was 0.60 (95% CI, 0.24-1.52; P = 0.2789).

Subcutaneous rituximab has been available in the European Union under the trade name MabThera since 2014, and is also approved in nearly 50 other countries.

The IV formulation of rituximab is currently approved by the FDA for patients with previously untreated FL, previously untreated DLBCL, relapsed or refractory low grade or follicular lymphoma, and previously untreated and relapsed or refractory CLL.