[This post is authored by Rishabh Upadhyay. Rishabh is an LL.M. candidate at the Faculty of Law, Delhi University, having completed his undergraduate legal studies at the Faculty of Law, Banaras Hindu University. His interest lies in intellectual property jurisprudence, with particular emphasis on Patent Law, Access to Medicines, and International Law.]
The Kerala High Court is set to conduct the final hearing in the long-running Ribociclib litigation today. In July, I had written (Part I, Part II) on this litigation, discussing why Sections 92 and 100 of the Patents Act were unlikely to produce a compulsory licence for Ribociclib, against the backdrop of the Court’s 15th July order. In its order, the Court had made a prima facie observation that the existence of Palbociclib, an off-patent CDK4/6 inhibitor, as an alternative might make any deliberations around compulsory licence or government use “purely academic.” The Court had then posed the interchangeability question to the National Cancer Institute, Jhajjar, Chittaranjan National Cancer Institute, Kolkata, the Regional Cancer Centre, Thiruvananthapuram, and the Drug Controller General of India. As per a press release by the Working Group on Access to Medicines and Treatment, the National Cancer Institute, Jhajjar, and Chittaranjan National Cancer Institute, Kolkata, have still not filed their submissions.
On the issue of interchangeability, CDSCO’s public drug approval database offers some details. Palbociclib’s listed approvals, dated 23 December 2020 and 6 August 2021, cover advanced or metastatic HR-positive, HER2-negative breast cancer, in combination with an aromatase inhibitor or fulvestrant (see screenshot below). Ribociclib’s database entries include two similarly worded approvals, dated 14 March 2019 and 4 October 2019, also for (locally) advanced or metastatic disease. However, CDSCO’s records show a third, more recent Ribociclib approval, dated 2 January 2026, specifically for adjuvant treatment of early breast cancer at high risk of recurrence (See screenshot below). No comparable early-stage indication appears against Palbociclib in the CDSCO database. Whether this difference in approved indications translates into a difference in clinical interchangeability is an open question, at least on the record so far. The Court has indicated it wants expert input rather than deciding on its own.
Emphasizing this point, the Working Group on Access to Medicines and Treatment highlighted that the affidavit filed by CDSCO had contradictory claims regarding the indications for which the drugs were approved, and the same misleads the Court. The press release also notes the submission made by Dr R. Ravi Kannan, an expert oncologist and Ramon Magsaysay Award winner, who intervened in the matter and underlined why the medicines are not interchangeable, and treating the two drugs as interchangeable across all stages risks denying patients access to the drug with a demonstrated early-stage indication, and has called for the government to bring down Ribociclib and Abemaciclib’s prices.
With final disposal listed for today, the central question remains whether Palbociclib can be treated as a perfect substitute for Ribociclib, and if not, in which contexts that holds. It will also be worth watching whether the Court makes any observations on Sections 92 and 100 if it finds Palbociclib isn’t the perfect substitute for Ribociclib.
