Trilaciclib shows myelopreservation benefits in patients with SCLC
medwireNews: Trilaciclib affords myelopreservation in individuals with small-cell lung cancer (SCLC) treated with first-line chemotherapy, without impacting treatment efficacy, research indicates.
Konstantin Dragnev (Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, US) and study co-authors write in Annals of Oncology that the first-in-class CDK4/6 inhibitor trilaciclib demonstrated “myelopreservation across multiple hematopoietic lineages resulting in fewer supportive care interventions and dose reductions, improved safety profile, and [at] no detriment to anti-tumor efficacy.”
The researchers first compared two doses of trilaciclib (phase Ib) ─ 200 mg/m2 and 240 mg/m2 ─ and found trilaciclib 240 mg/m2 to be superior on all measures, including adverse events and need for red blood cell and platelet transfusions.
This higher dose was then used in the phase II part of the study where it was compared with placebo in a respective 39 and 38 patients with extensive-stage SCLC. The treatments were administered intravenously prior to combined etoposide–carboplatin therapy on days 1 to 3 of each treatment cycle.
The researchers found that trilaciclib 240 mg/m2 successfully protected the immune system against the effects of chemotherapy, as only 5% of the individuals who received trilaciclib experienced severe neutropenia, compared with 43% of the individuals in the placebo group. Additionally, there were no cases of prolonged severe neutropenia (more than 5 days) among patients given trilaciclib, compared with a rate of 41% in the placebo group.
Trilaciclib also appeared to slow the rate of patients’ hemoglobin decline over time, with a lower absolute mean change from baseline, compared with placebo, and a reduced need for red blood cell transfusions per 100 cycles. These findings are in line with the mechanism of action of trilaciclib to preserve hematopoietic stem and progenitor cells.
The researchers highlight that “trilaciclib demonstrated improvement across multiple clinically meaningful myelosuppression endpoints, which currently cannot be addressed by a single existing intervention.”
Trilaciclib was not associated with increased toxicity. The rate of severe adverse events was comparable between the two groups, at 28.9% in patients who received trilaciclib and 24.3% in the placebo group, and trilaciclib was associated with fewer grade 3 or above adverse events, at a respective 50.0% versus 83.8%.
The researchers comment that “[w]hile the addition of trilaciclib to chemotherapy may increase the frequency of some low-grade toxicities (e.g. headache), this is outweighed by the clinically meaningful decrease in high grade (≥ Grade 3) toxicities.”
This was primarily due to the difference in major adverse hematologic events (MAHEs), which occurred in just 29% of the trilaciclib-treated group, compared with 81% of the placebo group. Additionally, the time to first MAHE was delayed with trilaciclib compared with placebo.
The researchers say: “These data support trilaciclib’s ability to improve the overall safety profile of this chemotherapy regimen.”
Lastly, they report that trilaciclib did not impair the ability of chemotherapy to treat the tumor, as demonstrated by a median progression free survival of 6.2 months for the trilaciclib group, compared with 5.0 months for the placebo group.
By Hannah Kitt
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