FDA Approves Polatuzumab Vedotin-Piiq for Diffuse Large B-Cell Lymphoma


‚ÄčThe FDA granted accelerated approval to polatuzumab
vedotin-piiq, a CD79b-directed antibody-drug conjugate indicated in combination
with bendamustine and a rituximab product for adult patients with relapsed or
refractory diffuse large B-cell lymphoma (DLBCL), not otherwise specified,
after at least two prior therapies.

Approval was based on Study GO29365 (NCT02257567), an
open-label, multicenter clinical trial that included a cohort of 80 patients
with relapsed or refractory DLBCL after at least one prior regimen. Patients
were randomized (1:1) to receive either polatuzumab vedotin-piiq in combination
with bendamustine and a rituximab product (P+BR) or BR for six 21-day cycles. Polatuzumab
vedotin-piiq, 1.8 mg/kg by IV infusion, was given on day 2 of cycle 1 and on
day 1 of subsequent cycles. Bendamustine (90 mg/m2 intravenously)
was administered on days 2 and 3 of cycle 1 and on days 1 and 2 of subsequent
cycles. A rituximab product (375 mg/m2intravenously) was administered on day 1 of each cycle.

Efficacy was based on complete response (CR) rate and
response duration, as determined by an independent review committee. At the end
of therapy, the CR rate was 40 percent (95% CI: 25-57%) with P+BR compared with
18 percent (95% CI: 7-33%) with BR alone. The best overall response rate
(complete and partial responses) was 63 percent with P+BR compared with 25
percent with BR. Of the 25 patients who achieved partial or complete response
to P+BR, 16 (64%) had response durations of at least 6x months and 12 (48%) had
response durations of at least 12 months.

The most common adverse reactions with P+BR (incidence at
least 20%) included neutropenia, thrombocytopenia, anemia, peripheral
neuropathy, fatigue, diarrhea, pyrexia, decreased appetite, and pneumonia.

Serious adverse reactions occurred in 64 percent, most often
from infection. Cytopenias were the most common reason for treatment
discontinuation (18% of all patients).

The prescribing information includes warnings and
precautions for peripheral neuropathy, infusion-related reactions,
myelosuppression, serious and opportunistic infections, progressive multifocal
leukoencephalopathy, tumor lysis syndrome, hepatotoxicity, and embryo-fetal
toxicity.

The recommended dose of polatuzumab vedotin-piiq is 1.8
mg/kg as an IV infusion over 90 minutes every 21 days for 6 cycles in
combination with bendamustine and a rituximab product. Subsequent infusions may
be administered over 30 minutes if the previous infusion is tolerated.
Premedicate with an antihistamine and antipyretic, and administer prophylaxis
for Pneumocystis jiroveci pneumonia and herpesvirus.

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