Clinicians are finding that forgoing the standard 800mg loading dose of zolbituximab and starting directly with the 600mg maintenance dose appears to mitigate acute gastrointestinal toxicity, particularly gastritis. This practical adjustment is being formally studied but is already used in practice to improve patient experience.

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Due to fedratinib's significant GI side effect profile and the logistical difficulty of measuring thiamine levels, clinicians should proactively provide patients with thiamine supplements, anti-emetics, and anti-diarrheal therapies. Instructing patients to take the drug with food can also help mitigate GI toxicity.

Clinical trials with zanidatumab revealed significant diarrhea primarily in the first cycle. The successful management strategy involves mandatory loperamide twice daily for the first seven days to improve tolerability and prevent treatment discontinuation, a crucial implementation pearl.

The failure of an adjuvant trial for the TKI pazopanib was likely caused by a protocol change that reduced the dose to manage transaminitis. While well-intentioned to improve tolerability and adherence, the lower dose was sub-therapeutic. This serves as a critical lesson that managing side effects by compromising dose can nullify a drug's potential efficacy.

Due to significant ocular toxicity affecting most patients, the approved starting dose for belantumab is likely not optimal long-term. Effective management requires clinicians to proactively hold, delay, and reduce doses at the first sign of side effects, meaning real-world application will differ from the initial protocol.

For patients over 75 with metastatic gastric cancer, a common practice is to reduce the oxaliplatin dose from 85 to 65 mg/m² and universally omit the 5-FU bolus from the FOLFOX regimen. This pragmatic approach aims to maintain efficacy while minimizing toxicity in a more vulnerable population.

The HORIZON-GEA-01 trial for zanidatumab in gastric cancer mandated prophylactic loperamide (4mg BID) for all patients. This was necessary to manage the high rates of diarrhea (up to 80% of patients), a significant GI toxicity associated with the drug's mechanism of action.

The Phase 2 TRAIT study suggests starting adjuvant abemaciclib at a lower dose and escalating over several weeks significantly reduces early discontinuations due to side effects like diarrhea. This strategy helps more patients get through the initial high-toxicity period and remain on the effective dose for the full two-year course.

As survival times for metastatic gastric cancer patients extend, managing long-term toxicity is paramount. Clinicians typically administer only 6-8 cycles of oxaliplatin to prevent severe, cumulative peripheral neuropathy, allowing for longer, better-tolerated maintenance therapy with biologics.

Clinicians advise against continuing targeted agents like zolbituximab or trastuzumab after disease progression in gastroesophageal cancer. The biological heterogeneity of this cancer type means that if a targeted therapy isn't working, it's unlikely to provide benefit with a different chemotherapy backbone.

Clinical trial data shows that despite specific toxicities, antibody-drug conjugates (ADCs) can be better tolerated overall than standard chemotherapy. For example, trials for both sacituzumab govitecan and dato-DXd reported fewer patients discontinuing treatment in the ADC arm compared to the chemotherapy arm.