The optimal duration of capecitabine plus temozolomide in patients with well-differentiated pancreatic NETs with or without maintenance therapy

Oxaliplatin-Based Versus Alkylating Agent in Neuroendocrine Tumors According to the O6-Methylguanine-DNA Methyltransferase Status: A Randomized Phase II Study (MGMT-NET)

PURPOSE

Alkylating agents (ALKY) are the main chemotherapies used for advanced neuroendocrine tumors (NETs). O6-Methylguanine-DNA methyltransferase (MGMT) status, as proficient (p) or deficient (d), may predict the response to ALKY.

PATIENTS AND METHODS

MGMT-NET (ClinicalTrials.gov identifier: NCT03217097) was a phase II trial randomly assigning 1:1 for pMGMT or 2:1 for dMGMT-NETs to either ALKY or oxaliplatin (Ox). Inclusion criteria were a confirmed advanced pancreatic, thoracic, or unknown primary NETs with an indication for chemotherapy and tissue available. The primary aim was to detect a difference of 35% between the 3-month objective response rate (ORR) in pMGMT-NETs versus in dMGMT-NETs when treated with ALKY. A biomarker-stratified design was performed to compare ALKY and Ox in the dMGMT and pMGMT strata for the secondary end points. dMGMT was defined using pyrosequencing (PSQ; methylated MGMT ≥9%) and using immunochemistry (H-score of MGMT <50) when PSQ was not interpretable.

RESULTS

From October 2018 to October 2021, 105 patients (55 pancreas, 38 thorax, 12 unknown) started either ALKY (n = 62) or Ox (n = 43). The median age was 63 years (range, 30-84), and 59% were males. NETs were G1 (19%), G2 (69%), or G3 (10%). Among patients with interpretable MGMT status, 56.9% (58 of 102) had a dMGMT-NET. The primary end point was not reached; the 3-month ORR was 10 (29.4%) versus 2 (8%), and the odds ratio was 3.5 (0.58-21.16), P = .172. However, best ORR (18 [52.9%] v 3 [11.5%]) and median progression-free survival (14.6 [95% CI, 7.2 to 22.1] v 11.3 [9.4 to 13.2] months) were higher for dMGMT-NETs versus pMGMT-NETs. MGMT status does not seem to affect the Ox efficacy.

CONCLUSION

Despite the fact that the primary end point was not reached, ALKY has clinical activity in patients with dMGMT-NETs.

Temozolomide duration and secondary hematological neoplasms: A literature review and implications for patients with neuroendocrine neoplasms

Evidence-based recommendations for the optimal duration and sequencing of temozolomide-based treatments in advanced neuroendocrine neoplasms are lacking. Here, we conducted a systematic review of the literature for a descriptive analysis of temozolomide-associated myelodysplasias and leukemias to guide treatment planning. A database search of PubMed and Embase was conducted to identify case reports and/or case series reporting secondary myelodysplasias or leukemias in the setting of temozolomide therapy. Key data items extracted from the studies were the temozolomide dose and duration, latency to hematological disorder, type of secondary malignancy and cytogenetics. Reported cases were summarized graphically. A total of 16 studies with 27 patient cases of therapy-related hematologic neoplasms were identified, all of which were case reports or case series. The median treatment duration and cumulative dose were 19 months and 18,000 mg/m² , respectively. Most patients (21/27) were diagnosed on, or after, 12 months, while only one patient was diagnosed before 6 months of treatment. Most of the patients were diagnosed, while still on treatment with temozolomide. Graphically, cases clustered around a cumulative dose of 10,000 to 30,000 mg/m² and a latency period of 10 to 40 months which translates to an approximate treatment duration of 12.5 to 37.5 months. Taken together, most reported treatment-related hematological neoplasms appear to develop on or beyond the 12-month mark, while patients are still on treatment with temozolomide. For patients with neuroendocrine neoplasms, where sequencing of multiple therapies is important, we suggest an approach to optimizing treatment duration by establishing disease response at 6 months before continuing further treatment and restricting treatment to or establishing closer vigilance beyond 12 months.