Following the remarkable success of Enhertu and Datroway, Japanese pharmaceutical giant Daiichi Sankyo is striving to solidify its leadership in the antibody-drug conjugate (ADC) segment. However, the path to expansion is becoming increasingly complex as these therapies move into earlier lines of treatment and face intensifying competition from major rivals.
Strategic challenges for Enhertu:
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Market expansion: Enhertu recently secured FDA approval for first-line treatment of HER2-positive breast cancer. This expansion represents a potential market of 24,000 patients across G7 countries.
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The maintenance dilemma: Despite superior efficacy, physicians are showing a tendency to switch patients to alternative maintenance regimens (such as Pfizer’s Ibrance or Tukysa) after achieving an initial response. This practice may shorten the duration of therapy per patient, potentially impacting projected revenues.
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Early-stage and personalization: Applying Enhertu in pre- and post-surgical settings (neoadjuvant/adjuvant) offers hope for potential cures but raises questions about the appropriateness of re-using the drug if residual disease persists.
The TROP2 battlefield with Datroway:
While Enhertu has established its dominance, Datroway is facing head-to-head competition with Gilead’s Trodelvy and Merck’s up-and-coming sac-TMT.
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Competitive edge: Datroway is gaining traction due to its once-every-three-weeks dosing schedule, which is less frequent than Trodelvy’s regimen.
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Pressure from rivals: Merck is accelerating its efforts with 16 phase 3 clinical trials and has recently secured a priority voucher to shorten its time-to-market.
Risk management and safety:
The continued success of Daiichi’s ADC portfolio depends heavily on managing side effects, particularly interstitial lung disease (ILD). A recent clinical hold on a Merck-partnered program following ILD-related deaths serves as a critical reminder of the need for medical sites to be acutely aware of and act fast on early symptoms.